Ameren Service Manual 11-21-2022
Ameren Service Manual 11-21-2022
Ameren Service Manual 11-21-2022
SERVICE
MANUAL
BuildWithAmeren.com
ELECTRIC SERVICE 1
MANUAL 11/01/2022
AMEREN ELECTRIC SERVICE MANUAL
The information in this manual provides guidelines necessary to expedite the connection of electric service.
Where details are shown, they are provided to assure the safety of individuals in the immediate vicinity of the
electric service entrance.
1. As an Ameren Customer, the Customer's representative, the Customer's contractor, or the Customer's
engineer, it is your responsibility to ensure that equipment is installed in a condition acceptable to and
approved by the governmental inspection authority having jurisdiction in the territory in which the
Customer’s Premises is located, or, where no authority exists, in accordance with Ameren's standards,
the requirements of the latest edition of the National Electrical Code ("NEC"), the latest edition of the
National Electrical Safety Code ("NESC"), and any other applicable codes.
2. As an Ameren Customer, you are responsible for any damage, alteration or interference with Ameren's
metering or other electrical equipment on Premises.
3. The Customer further understands that they are required to secure and pay for all permits required by
the constituted authorities for the installation and operation of the electrical wiring and other electrical
equipment on the Premises, and that Ameren must receive notice of the approval from said authorities
prior to connection unless (1) the authority having jurisdiction has in writing waved this requirement or
(2) in areas where there is no inspection authority.
4. The Customer understands that Ameren may, but is not required to, identify wiring and electrical
equipment practices that may raise safety and/or reliability concerns for Ameren and / or the Customer
on the Customer's side of the point of delivery, including beyond the service disconnecting means.
Ameren reserves the right to identify and require the correction of safety and/or reliability concerns
prior to connection of service. Ameren retains the right to refuse or terminate the connection of service.
5. To the extent that Ameren does identify wiring and electrical equipment practices that may raise safety
and/or reliability concerns for Ameren and/or the Customer on the Customer's side of the point of
delivery, the Customer or the Customer's representative should understand that said identifications are
not being made by certified inspection authorities and should be verified by a certified inspector and/or
local governmental authorities having jurisdiction.
ELECTRIC SERVICE 2
MANUAL 11/01/2022
AMEREN ELECTRIC SERVICE MANUAL
Foreword: Ameren is committed to providing a quality reference guide that facilitates
the planning and installation of electrical equipment in a safe and professional manner.
The Electric Service Manual incorporates Company Metering Requirements, Standards,
and language in Company filed Schedule of Rates for Electric Services. This manual
serves as a supplement not a replacement for the National Electrical Code, National
Electrical Safety Code, and any local authority guidelines. Qualified users of this
manual should contact Ameren representatives for clarification of requirements and
specifications. All electrical service wiring and equipment where Ameren owned conductors
will be terminated, or that will contain Ameren owned metering equipment, shall be
listed, and used for the intended purpose as defined in the NEC, and shall be approved by
Ameren.
For Ameren Missouri, there will be a grace period for compliance of the new requirements
for the outdoor disconnect and surge protection per 2020 NEC found in Section 300 until
January 1, 2024.
• Ameren Missouri:
Residential 1-800-552-7583
Business 1-877-426-3736
• Nationwide: 811
• Illinois (JULIE): 800-892-0123 or www.illinois1call.com
• Missouri (DIG-RITE): 800-DIG-RITE (344-7483) or www.mo1call.com
ELECTRIC SERVICE 3
MANUAL 11/01/2022
AMEREN ELECTRIC SERVICE MANUAL
TABLE OF CONTENTS
150. GLOSSARY
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Section 100
General Information
1910.29 - Fall protection systems and falling object protection-criteria and practices, including
handrails
Always consult with Ameren prior to purchasing material and construction of elevated metering platforms.
Electric service is available to any Customer located in Company's Service Area. Customer will agree to
abide by Company's Terms and Conditions, Standards and Qualifications for Electric Service and any
other requirements of the Schedule of Rates for Electric Service. The standard electric service furnished
by Company is 60 Hertz alternating current.
100.04 COMPANY OBLIGATIONS
Company shall furnish service within a reasonable length of time dependent upon the availability of labor
and material and after all necessary permits / easements and approvals are obtained from the customer
and others.
100.05 POINT OF DELIVERY OF SERVICE
“Point of Delivery” means the point at which the entity providing distribution facilities connects its lines or
equipment to the lines or facilities owned or rented by the Customer, without regard to the location or
ownership of transformers, substations, or meters, unless otherwise provided for by written contract or
tariffs.
100.06 DISCONNECTION AND RECONNECTION OF SERVICE
The Company has the right to discontinue service to any Customer and remove its property from
Customer's Premises, after due notice. If Customer wiring and equipment is found to be unsafe or
unsuitable to receive electric service and a harmful condition exists, Company reserves the right to
terminate service immediately. A Customer's service that has been disconnected shall be reconnected
after customer has furnished satisfactory evidence of compliance with the Company's Terms and
Conditions and paid all applicable fees and charges. For additional information, go to:
Ameren Illinois:
Ameren Illinois Standards and Qualifications for Electric Service
Ameren Missouri:
Ameren Missouri General Rules and Regulations – Disconnection and Reconnection of Service
100.07 CUSTOMER OBLIGATIONS
Inform Company as to the size and characteristics of the load that is to be initially and thereafter served,
the location of the Premises, the need date, and any special circumstances or conditions affecting the
supply of electric service by Company. Customer is responsible for securing information from Company
regarding available facilities at a particular location.
For Ameren Illinois, refer to Standards and Qualifications for Electric Service in Ameren Illinois for
additional information.
For Ameren Missouri, refer to General Rules and Regulations in Ameren Missouri for additional
information.
100.08 LIMITATION OF LIABILITY
The Company will use reasonable diligence in furnishing uninterrupted and regular Electric Service, but
will in no case be liable for interruptions, deficiencies, or imperfections of service, except to the extent
of a prorate reduction of the monthly charges. Refer to Customer Terms and Conditions for additional
information.
100.09 METER TAMPERING
The Company shall have the right to discontinue electric service to any Customer and remove its property
from Customer premises, if there is evidence found of tampering with any meter or service wiring leading
thereto, and where such tampering is for the purpose of reducing the registration of the Customer's electric
consumption. See Customer Terms and Conditions pertaining to your service provider for additional
information.
100.10 NUMBER OF SERVICES
The Company will normally provide service to Customer at only one Point of Delivery on each premises.
The point on the Company's system where the Service Extension will terminate will be as designated by
the Company. The Company may agree to provide service through multiple delivery points as described
in the Excess Facilities section of the Standards and Qualifications for Electric Service in Illinois.
The Company may agree to provide service through multiple delivery points as described in the Special
Facilities section of the General Rules and Regulations for Electric Service in Missouri.
100.11 ORIGINAL EQUIPMENT MANUFACTURER (OEM)
OEM, or “Original Equipment Manufacturer,” is a company that has the capabilities to design, develop,
manufacture, and sell products themselves.
S The electrical contractor is licensed in the county or municipality where the work is to be completed.
S The service is a single residential Ameren Missouri customer.
S The meter is a typical residential type of electric meter (120/240V, single phase, self-contained).
S The service size will remain the same after the work is completed.
S The same meter will be removed and reinstalled during the same day.
S The billing account is active at this service location.
If ALL the above conditions apply, the contractor must complete the following requirements before
proceeding with the work:
S Call Ameren Missouri construction Services Hotline at 866-992-6619 (M-F, 7am to 5:30pm) to
obtain approval; notification to be made within 24 hours of performing the intended work.
If ALL the above conditions DO NOT APPLY, call 866-992-6619 to schedule Ameren Missouri
personnel to perform the work.
Ameren Electric Service Manual (ASM): Company reference guide that facilities the planning
and installation of electrical equipment in a safety and professional manner.
Ampacity: The current in amperes a conductor can carry continuously under the conditions of
use without exceeding its temperature rating.
Applicant: A person who applies for Residential or Non-Residential service and / or who
requests an Extension. This would also include an entity / person who applies for a Distribution
Generation (DG) / Distribution Energy Resources (DER) interconnection.
Bonding Conductor: The conductor that provides the electrical conductivity between metal
parts that are required to be electrically connected.
1. When the lever is downward in its default position, the mechanism provides jaw clamping
forces to help secure the meter and make continuity to the meter spades while in normal
operation.
2. When the lever is shifted to the upward position, into "bypass” mode, the mechanism
releases the clamping pressure on the meter spades and diverts the current flow from the
meter to the internal bypass. This allows for the exchange, inspection, or repair of a meter
without service interruption to the customer. Note: Meter socket cover cannot be
reinstalled or sealed with lever handle in upward "bypass” position.
Commission: The agency responsible for regulating the regulated portions of investor-owned
public utilities.
• In Illinois, the Illinois Commerce Commission (ICC) or any duly constituted successor
• In Missouri, the Missouri Public Service Commission (PSC) or any duly constituted
successor
Company: Either Ameren Illinois Company or Ameren Missouri Company, depending on the
geographic location of the facilities to be installed.
Customer or Retail Customer: A person or legal entity receiving service at a premises or whose
facilities are connected for utilizing services at the premises.
Delivery Voltage: The service voltage of Company's lines at the Point of Delivery.
Demand (Peak Demand): The highest average load in kilowatts (kW) during any 15-minute
interval during the time between regular meter readings. There shall be four fixed 15-minute
intervals per hour with the first interval beginning at the top of the hour as registered on the meter.
Distributed Energy Resources (DER): Systems that operate in parallel with Ameren supply such
as photovoltaic, wind, energy storage systems (ESS) such as battery or flywheel, diesel / natural
gas or other technologies.
Energy Storage System (ESS): A subcategory of DER. Batteries are the most common form of
equipment under this DER category.
Electrical Metallic Tubing (EMT): An unthreaded thin-walled raceway of circular cross section
designed for the physical protection and routing of conductors and cables and for use as an
equipment grounding conductor when installed utilizing appropriate fittings. EMT can't be used
for supporting meter structures or for making service drop terminations above the roof line.
Electrical Nonmetallic Tubing (ENT): A nonmetallic, pliable, corrugated raceway of circular
cross section with integral or associated couplings, connectors, and fittings for the installation of
electrical conductors.
Ground: A conducting connection, whether intentional or accidental, between an electrical circuit
or equipment and the earth, or to some conducting body that serves in place of the earth.
High Rise Development: A commercial / residential structure which may contain a mixture of
both class of tenants, consisting of 4 or more floors that may have grouping of tenant meters in
electrical rooms found on multiple floors.
Illinois Commerce Commission (ICC): See Commission
Line (Supply) Side Tap for DER: A tap made where the DER Point of Interconnection (POI) is
located electrically after the revenue metering equipment but before the main service
disconnecting means.
Load Side Tap for DER: A tap made for adding DER to a secondary or primary rated service
installation where the Point of Interconnection (POI) is located electrically after the main service
disconnect.
Local Inspection Authority and Authority Having Jurisdiction (AHJ): As it pertains to this
document, the agency responsible for the inspection of a customer's electrical installations. This
authority can be an agency of an incorporated City, Town, Village, or of the County, State, or
Federal Government. The Ameren Companies are not inspection authorities. In service areas
void of inspection authority, Customer service installations must conform to Ameren Electric
Service Manual standards and the current National Electrical Code (NEC), and other applicable
codes.
Meter Disconnect: A safety switch that is located on the line side of a 480Y/277V, 480/240V, or
480V system. The disconnect must be a knife blade switch without overcurrent protection (OCPD).
Meter Socket, Self-Contained: The mounting device consisting of jaws, connectors, and
enclosure for socket type meters where no CTs or PTs are used.
Meter Socket, Instrument Transformer Rated: The mounting device consisting of jaws,
connectors, and enclosure for socket type meters where CTs and / or PTs are used.
Metering Instrument Transformer, Current (CT): A device that precisely steps down the current
from its primary current to a workable current that can be measured with conventional meters.
Metering Instrument Transformer, Potential (PT): A device that precisely steps down the
voltage from its primary voltage to a workable voltage that can be measured with conventional
meters.
Missouri Public Service Commission (PSC): See Commission
Multi-Tenant: (Illinois applications) A multiple occupancy building with three or more Customers
who each qualify for the Residential rate or two or more Customers who each qualify for a non-
Residential rate or buildings with one commercial and one residential service.
Multiple-Occupancy Dwellings: (Missouri applications) structures for permanent occupancy of
2 or more single-family residences.
National Electrical Code (NEC): This is the code document that governs building and premise
wiring.
National Electrical Safety Code (NESC): This is the code document that governs electric and
communication utilities.
Premises: A contiguous tract of land separated by nothing more than a highway, street, alley, or
railroad right-of-way, where all buildings and/or electric consuming devices located thereon are
owned or occupied by a single Customer or applicant for electric service, or where all electricity
delivered thereto is utilized to supply one or more buildings and / or electrical loads which the
Company considers as components of a unified operation.
Rigid Metal Conduit (RMC): A threadable raceway of circular cross section designed for the
physical protection and routing of conductors and cables and for use as an equipment grounding
conductor when installed with its integral or associated coupling and appropriate fittings.
Galvanized Steel RMC is permitted to be installed in all atmospheric conditions, in concrete, in
direct contact with the earth, or in areas subject to severe corrosive influences. Aluminum
RMC is permitted to be installed where approved for the environment and were protected by
corrosion protection when encased in concrete or direct contact with the earth. Both aluminum
and steel RMC are permitted to be installed where subject to severe physical damage. Only
Galvanized Steel RMC is allowed to be used for support of meter / service equipment structures
and service riser masts extending above the roof.
Sequence, Cold Sequence Metering: An installation where a safety switch is located on the line
side of metering equipment of a 480Y/277V, 480/240V, or 480V system. The safety switch must
be a knife blade switch without overcurrent protection (OCPD).
Sequence, Hot Sequence Metering: An installation where a breaker, fused disconnect, or pull-
out type fused switch is located on the load side of the metering equipment and where there is no
safety switch on the line-side of the meter.
Service: As used in this document, service refers to the conductors connecting a point of delivery
to the utilization voltage of the electric distribution system serving the customer.
This definition should not be confused with the Illinois tariffs, which define Service Extension, for
the purpose of calculating Extension charges, as the portion of the extension, dedicated to the
Customer, on Customer's Premises, regardless of voltage.
Service Equipment: The necessary equipment, usually consisting of a circuit breaker or switch
and fuses, and their accessories, located near the point of entrance of supply conductors to a
building or other structure, or an otherwise defined area, and intended to constitute the main
control and means of cutoff of the supply.
Surge Protective Device (SPD): A device designed to protect electrical equipment from voltage
spikes by blocking or shorting to ground any unwanted voltages above a safe threshold.
Underwriters Laboratories Inc (UL) and Intertek Testing Services (ETL): Ameren approved
equipment testing laboratories for the equipment used and installed in accordance with the listing
and labeling instructions.
“Visible Open” Disconnect: A knife blade safety switch that may or may not have fuses, or a
manually operated circuit breaker that plainly indicates whether in the open (OFF) position or
closed (ON) position. (Refer to ASM Sections 1400 and 1500).
Witness Test: A testing procedure where DER systems are conducted by the Utility to ensure
these systems meet certain established criteria prior to granting PTO.
9) For Ameren Missouri areas served by heavy underground and secondary network systems,
refer to ASM Section 1300 for special metering requirements.
10) Rules Defining Rewire Work and Meter Location on Existing Buildings
a) Rewire work is defined as electrical work that involves changes to customer owned service
cables, service entrance conductors, meter socket, or service entrance equipment for any
of the following reasons:
i) Relocation
ii) Replacement
iii) Ampacity changes
Rewire work shall include the updating of metering equipment and requires that all meters
be installed and located in accordance with the requirements of the latest Ameren Service
Manual.
Service entrance conductors are defined as the conductors between the terminals of the
service equipment and the tap to the service drop, service lateral or secondary distribution.
Service equipment is defined as consisting of the circuit breaker(s) or switch(s) and fuse(s)
and their accessories located adjacent to the meter or near the point of entrance of the
supply conductors to a building and intended to constitute the main control and means of
disconnect from the supply.
b) Additional Service Entrances:
i) On existing residential buildings of 15 meters or less (on three occupied floors or less),
additional service entrance conductors and / or an increase of ampacity requires all
meters to be relocated outdoors per the meter location policy.
ii) On existing residential buildings exceeding 15 meters (on three occupied floors or less),
if additional service entrances are wired to the building, meters associated with the new
services shall be located outdoors if there are 15 or less meters per additional service
entrance. Exception: If the total of existing and new meters exceeds 15 and all meters
and services are in one approved location, meters may remain indoors.
c) Rewire exceptions:
i) In multi-tenant buildings of six units or less, with indoor meters, where all units are
served from a common service and each unit has its own means of disconnect, the
ampacity of the tenant disconnect, or the main service disconnect may be increased
without relocating the meter(s) outdoors subject to the limitation of the service entrance
conductor ampacity. Work to increase the service entrance conductor ampacity;
however, is rewire work and requires all indoor self-contained meters on the service to
be relocated outdoors.
ii) The CTs for rewired 800 amperes services may be left indoors if the rewiring can reuse
the existing CT enclosure, which must meet current Ameren specifications. Appropriate
CTs shall be installed. The meter will be located outdoors.
d) Supplemental Guidance on Existing Self-Contained Meter Socket Installations:
This section provides further clarifications regarding when a clamp-jaw lever bypass meter
socket may or may not be required for existing electrical service installations. The following
scenarios reference existing non-clamp-jaw lever bypass meter socket installations that
need planned maintenance or replacement. In all cases, final determination and approval
is requirement by the local Ameren personnel.
1) Single Self-Contained Meter Installation (e.g., not gang-metered):
a. When a meter socket is reasonably repairable with original equipment manufacturer
(OEM) equipment (e.g., meter socket lug replacement), Ameren may allow for the
existing meter socket to be repaired and not require replacement with a clamp-jaw
lever bypass device.
b. When a meter socket is not reasonably repairable in which functionality and / or
safety is compromised, the customer must replace the meter socket with a
clamp-jaw lever bypass device.
c. When a customer is replacing the main breaker / panel only with the same
ampacity (e.g., replacing old 200A with new 200A panel):
i. Outdoor Metering
1. Ameren Missouri may allow for the existing non-clamp-jaw lever bypass meter
socket to remain, if the device (1) is in good working order, (2) meets local
inspection authority requirements, and (3) is approved by Ameren Missouri.
2. Ameren Illinois requires the customer to update self-contained metering
equipment that does not include a horn-bypass or lever-bypass meter socket
(e.g., a ring-type meter socket). Replacement of horn-bypass or lever-bypass
meter sockets for rewire work may still be required depending upon Ameren's
field evaluation of the meter socket's condition.
ii. Indoor Metering: Existing indoor meter installation being rewired by a customer
must be relocated outdoors as defined in this ASM section. This requires a
clamp-jaw lever bypass meter socket as defined in ASM Section 1000 to be
installed.
1) General Requirements
a) In exceptional cases where it is physically impractical to make outdoor installations, as in
the case of large apartment houses or where there is no suitable outdoor location, meters
may be installed indoors, with Company approval.
b) Meters shall be mounted on a rigid wall or panel which is free from vibration.
c) Meters shall be in a clean, dry, and safe place as near as practical to the point where the
service entrance enters the building.
d) Meters shall not be in sheds, attics, bedrooms, living rooms, bathrooms, restaurant
kitchens, stairways, ventilating shafts, closets, coal bins, coal furnace rooms, or in any
location where the visits of Company employees will inconvenience either the customer or
the employee.
e) Meters shall not be in basements or in other locations which are not accessible by
permanent stairs. A ladder cannot be accepted as a substitute for stairs.
f) Meters and service equipment installed indoors for a multiple-occupancy building, shall be
grouped in an accessible public space where the Building Management and Ameren
Representatives always have access. If the meter room(s) is locked and a key is not readily
accessible from the customer, Ameren will provide a key lockbox for customer to mount
adjacent to the access door. The Ameren lockbox stock number is 22 13 066.
g) In cases where there are several floors and several customers on each floor, thus making it
impractical to locate the meters in one location, the meters may, with Company approval,
be grouped in an accessible public space on designated floors.
h) In Ameren MO, indoor installation for smart metering will depend on the type of building
approval (easement or lease) Ameren has secured and uploaded to the Real Estate
Management System (REMS). Indoor installation of the Network Gateway/Router will
consist of running a 1-1/2 in. conduit from the device located preferably in the meter room
(but not limited to this location) to a Hoffman 6 in. x 6 in. box (part # AHE6x6x4 or
comparable) for direct power. If the device is in a building that has a dedicated outlet that is
inaccessible for use to building personnel, this is also an acceptable method to power
the device.
i) In Ameren IL, for new building construction or renovation, every electrical room that has
indoor metering sockets must have a dedicated 20 amperes power outlet served from a
dedicated circuit with overcurrent protection installed at no cost to Ameren by the building
owner. The outlet shall provide a 120 volt source for AMI equipment. This outlet must have
a lockable in-use cover and be located above the bank of meters and within 3 ft. of the
ceiling. This outlet must be labeled as “Ameren Use Only”. For existing buildings, Ameren
IL will provide meter socket adapters, where required, to provide a 120 volt source for AMI
auxiliary equipment. An AMI network device, such as a collector, will be mounted on the
wall near the ceiling and adjacent to the dedicated power outlet in locations where AMI
signal strength is weak. New construction also requires the customer to install a 1-1/2 in.
schedule 40 PVC conduit in a ground floor or basement electrical meter room(s) from the
Ameren dedicated power outlet to an exterior wall where a Hoffman 6 in. x 6 in. box (part
# AHE6x6x4 or comparable) is mounted at ladder height. This conduit will be utilized
when an AMI antenna needs to be installed outdoors for network connectivity.
Where an AMI device, other than a meter, is installed inside the building or on an exterior
wall, an agreement must be prepared by Ameren and jointly entered with the building
owner. This agreement is referred to as a Wireless Telecommunications Device License
or Wireless Telecommunications Device Lease, depending upon the circumstance. This
agreement is secured by the local Ameren Real Estate Agent and entered into the Real
Estate Management System (REMS), in addition to being recorded at the appropriate
county courthouse records department. Since this agreement is required only because of
allowing some revenue meters to be installed indoors in special metering situations at the
request of the building owner, no compensation to the building owner for energy
consumption to support these AMI devices or for usage space allocation shall be made by
Ameren or it's assigns.
j) If a customer makes additions or rearrangements to his building which result in metering
equipment being located or enclosed in a location unacceptable to the Company, the
customer shall relocate metering equipment and service entrance at his expense within 30
days of written notification.
2) Specific Installations
These situations are:
a) In designated underground areas of Ameren Missouri, such as Downtown St. Louis and
Clayton, if supplied from indoor transformer rooms or network manholes or vaults, refer to
ASM Section 1300 for more details.
b) In designated underground areas of Ameren Illinois, if supplied from indoor transformer
rooms, network manholes or vaults, refer to ASM Section 1350 for more details.
c) General Service Rate (Non-residential) CT enclosure for underground services and CT
enclosures for overhead services greater than 800 amperes, if approved by Field Metering
Supervisor and Field Supervising Engineer, may be located indoors. For such installations,
provisions must be made by the building owner for immediate doorway access to the
service equipment room from the outdoor meter location. Any variances from this policy
must be approved by the Field Metering Supervisor and Field Supervising Engineer. CT
enclosures for overhead services 800 amperes or less and all residential services shall be
located outdoors. The associated meter socket for all CT rated meters shall usually be
mounted outdoors unless approved indoors by Field Metering Supervisor and Field
Supervising Engineer.
d) Multiple Occupancy Buildings:
1) Residential Service Rate - three (3) occupancy floors or less with sixteen (16) or more
meters per service allowed indoors. Fifteen (15) or less meters per service must be
located outdoors.
2) General Service (Non-residential) Rate - three (3) occupancy floors or less with seven
(7) or more meters per service allowed indoors. Six (6) meters or less per service must
be located outdoors.
200.03 INSTALLATION
1) The customer shall furnish and install, at customer's expense, all necessary service entrance
facilities.
2) All metering equipment shall be fastened in place with corrosion resistant (galvanized or
stainless steel) screws.
3) Anchoring to supply adequate support shall be used on brick, tile, or other types of
masonry buildings.
4) Where necessary on hollow tile walls, corrosion resistant (galvanized or stainless steel)
toggle bolts may be used.
5) Meter boards no less than ¾ in. thick shall be installed by the customer on indoor
locations where plastered walls and other direct mounting surfaces are of insufficient
strength.
6) Use of sheet rock style screws will not be accepted as fasteners for service entrance
equipment on any installation.
7) All fasteners and straps must be of adequate size and material to rigidly secure the equipment
to the structure.
9) Line or service entrance cable, conduit or bus duct shall enter the hubs of meter sockets and
transformer enclosures on all overhead service installations, except where a customer's main
line switch or a junction box is installed on the line or source side of the metering equipment.
10) All unused openings of service equipment and metering sockets shall be closed with internally
secured hub plugs or plates to afford protection nearly the same as the solid wall of the cabinet
or enclosure.
11) Insulated splicing wire connectors, commonly referred to as twist caps or wire nuts, shall not be
used on service entrance conductors.
12) Lock nuts and bushings shall be used where conduits enter the back, bottom or side knockouts
of sockets or enclosures.
13) Inhibitor is required on service conductors at meter socket terminators if unlike materials are
used.
14) The neutral conductor shall be identified with one of the following methods:
b) A conductor with three continuous white or gray stripes on other than green insulation
c) A marking of white or gray color tape at its terminations during the time of installation
15) Grounded delta 3-phase sockets require high leg / wild leg to be placed in the right-hand
position at the meter socket, and this conductor will be marked orange in color. The high leg
(also referred to as the wild leg) will terminate in the middle position on the customer main
service disconnect, except in panel boards / switchgear arrangements, ahead of and beyond
metering compartments.
16) Above grade, unmetered service entrance conductors must be run in a continuous conduit
system. (An exception would be type SE cable.) LB's, troughs, or any other connectors that do
not have provisions for Company seals or installation of tamper proof screws that would allow
access to un-metered conductors on the supply side of Ameren metering equipment (e.g., CT
enclosure or self-contained meter socket) are not permitted without specific approval from the
Field Metering Supervisor and Field Supervising Engineer.
b) If local inspection authority or the load of the fire pump and protection equipment
require more than a 200 amperes service, then a CT / PT enclosure must be used
(e.g., 320 / 400 amperes meter socket not allowed) as described in ASM Section
1001.02. If the service to the fire protection equipment can be sized at 200 amperes or
below, then Ameren will still require a meter disconnect in front of the meter socket.
c) Ameren should be contacted to determine available short circuit current.
d) Use of separate enclosures for the line side meter disconnect (safety switch) and the
meter socket is acceptable. However, they must be mounted directly above, or on a
horizontal plane, within 4 feet of one another.
e) Continuous conduit is required with no LB's or any other connector that could allow
access to un-metered wiring between the meter disconnect (safety switch) enclosure
and meter socket.
f) Sealing provisions for the line side meter disconnect (safety switch) must be provided
to prevent access to un-metered conductors within this enclosure.
g) The meter disconnect (safety switch) shall be provided by the customer and secured
with a pad lock by Ameren for Company use only.
2) 201-400 amperes:
A. Single-phase 120/240 volts; 3-phase 3-wire 240 volts; 3-phase 4-wire 240/120 volts; and
3-phase 4-wire 208Y/120 volts
a) The use of K-base meter socket will not be allowed on new service installations.
b) Self-contained meter sockets rated at 320 amperes continuous / 400 amperes max
are normally required for this ampere range.
c) The customer installed main service disconnect (overcurrent protection device) must
limit the total continuous load current (defined as 3 hours or more by NEC) to 320
amperes. This is ONLY accomplished by installing one of the following options with
Standard Rating of 80%:
MISSOURI
Figure 200-4 ELECTRICAL AND GAS EQUIPMENT ON SIDE OF HOUSE
OR COMMERCIAL BUILDING
APPLICABLE
UNDERGROUND
METER SOCKET 54” Min 54' Min
78”
66” Max 66” Max
4 Max 36”
78”
MIN
18” Min Indoor Max
24” 24” Min Outdoor
Min
36' Min
66” Max
MANUAL
FINAL GROUND
Section 200
Figure 200-1
ELECTRIC SERVICE
Metering Requirements
30” OR
WIDER
78”
Max
ELECTRICAL
EQUIPMENT GROUND LINE
ENCLOSURE
AT WALL
11/01/2022
200-11
EQUIPMENT ENCLOSURE
REFER TO FIGURE 200-4
Section 200
Metering Requirements
WALL
ENCLOSURE 12”
18” 18”
6” 6”
4” SCHEDULE 40
PLAN VIEW
GALVANIZED RMC FILLED TO TOP
WITH CONCRETE.
GENERAL
SERVICE
METER
SOCKET
6” 6”
5'
CONCRETE
(EMBED 3 FT. DEEP)
ELEVATION
TOP VIEW C
1
FRONT B
TOP VIEW C
1
FRONT B
FIRST FLOOR
OPERABLE WINDOW 3 1 2
30” OR WIDER
6"
78' MAX
GROUND LINE
FRONT OF BUILDING
1 2 3 ELECTRICAL
GAS AT WALL
EQUIPMENT
REGULATOR ENCLOSURE
AC UNIT
GROUND LEVEL
4
TOP VIEW
3' OR 15'
4
NO SOURCE OF IGNITION
WITHIN 3' OR 15' SPHERICAL
AC UNIT
RADIUS OF RELIEF VENT
B. Service equipment / main disconnecting means that have circuit breaker overcurrent
protection that has a trip rating or setting less than the enclosure shall have a
permanent placard stating the enclosure rating and the max trip rating in the form of XX
AS / YY AT MAX (e.g., 3000 AS / 2000 AT MAX).
Exception: If service conductor rating meets or exceeds that of the enclosure, placard
is not required.
C. A & B are applicable to main disconnecting means as well as DER / DG and ESS
disconnecting means that include overcurrent protection.
D. Placards shall be phenolic and when secured to the outer cover of the electrical
enclosure shall be adhered using permanent adhesive. When the surface area of the
electrical enclosure does not permit attachment, the placard is permitted to be adhered
to a wall or immediately adjacent surface. Placards shall not overlay critical
equipment information such as ON / OFF designations or equipment ratings and
shall not overhang the surface of the equipment to which they are attached.
4. A building or other structure served by the Company shall be supplied by only one service
which could be multiple runs of conductors connected at the supply end or connected at
both the supply end and meter point. Allowed exceptions to this but not limited to:
A. Fire pumps
B. Emergency Systems
C. Legally required standby systems
D. Optional standby systems
E. Parallel production systems
F. Systems designed for connection to multiple sources of supply for the purpose of
enhanced reliability
G. Buildings or structures too large causing excessive voltage drop on customer
distribution or demand greater than the Company can serve from a single point.
For any of the above exceptions allowed per the latest edition of the NEC, these
connections will be subject to Company approval. Contact Company during the
engineering / planning phase to ensure the needs of Company and Customer will be
met.
5. More than one disconnect or circuit breaker for the service equipment:
A. The service equipment shall contain no more than six operative switch positions,
and all shall be grouped together as allowed per 2020 NEC Article 230.71 (B):
1) Separate enclosures with a main service disconnecting mean per enclosure.
2) Panelboards with a main service disconnecting means in each panelboard.
3) Switchboard(s) where there is only one main service disconnecting means in
each separate vertical section where there are barriers separating each vertical
section.
4) Main service disconnects in switchboard or metering centers where each main
service disconnect is in a separate compartment.
B. No more than two service entrance masts per meter point location when served
overhead, without prior Company approval.
6. Main Service Disconnect(s) serving native customer loads for an electric service must be
grouped together. Where the main service disconnecting means is comprised of more than
a single switch but not greater than six switches as allowed per NEC, each must be labeled
"Main Service Disconnect" – 1 of the totals (i.e., 1 of 6). When a customer adds
generation, these Lockable AC Generation Source Disconnect(s) must also be grouped
together. This does not mean they have to be in the same room or located beside Main
Service Disconnect(s). The Lockable AC Generation Source Disconnect(s) (not to
exceed 6) are located outside, and the Main Service Disconnect(s) may be either inside
or outside. As customers expand their Renewable Sources, they may also install an
Energy Storage System (ESS). ESS Disconnect(s) must also be grouped together (not
to exceed 6) but may not be necessarily in the same vicinity as the Main Service
Disconnect(s) and the Lockable AC Generation Source Disconnect(s).
The label or placard found on these alternate generation and storage systems must state
"Lockable AC Generation Source Disconnect" and "Energy Storage System
Disconnect". In addition, where two to six Lockable AC Generation Source Disconnects
and / or two to six Energy Storage System Disconnects exist, they must also be labeled
as such (i.e.: 1 of 6).
Where multiple sources of power (utility grid, parallel generation, energy storage system,
and standby generation, etc.) serve a premises, and the associated service disconnects
are located more than 10 ft. apart or not visible from one location, placards must be
posted at each service disconnect showing where each source of power to the premises is
located. Each category of service disconnects (categories include PV, ESS, main service
disconnects, etc.) must be grouped together and visible from one location (each category
must be on same side of wall and not separated by partitions).
These placards shall be in the form of a site map (preferred) or a directory clearly listing the
locations of each disconnect category. The placards or directories shall be permanently
adhered to the front-facing surface of the disconnect(s), without overhang, or on the
adjacent wall. When applied to electrical equipment, these can only be adhered using
permanent adhesive (not screws or rivets). These placards or directories must be made of
two layered engraved plastic (phenolic) material.
This extensive labeling or placarding is required so that first responders (i.e.: homeowners,
utility workers, emergency responders) can quickly identify all sources of power that supply
a premises.
7. Equipment must be certified by an approved independent testing laboratory using the
appropriate UL standard(s) for certification. At present Ameren recognizes UL
(Underwriters Laboratories) and ETL (Electrical Testing Laboratories) as approved testing
laboratories for equipment installed on the Ameren system.
8. Equipment being used as Service Disconnecting Means (Main Service Disconnect, AC
Generation Source Disconnect, Energy Storage System Disconnect, Fire Pump
Disconnect, etc.) must be labeled as “Suitable for Use as Service Equipment" (SUSE) or
“Suitable Only for Use as Service Equipment.” See definitions in ASM Section 150.
9. The Customer or the Customer's representative is responsible for specifying disconnecting
means rated and listed for the overcurrent, fault current (duty), and arc flash energy present
at that specific location. Contact your local Ameren engineering representative for fault and
impedance data available at the point of delivery.
** Disclaimer: The provided values are based on Ameren's current system configuration.
Due to the dynamic nature of the subtransmission and distribution systems, the
possibility exists for the values to change with future projects and maintenance work.
The provided values do not account for other customer equipment on the system, only
for Ameren owned equipment. Equipment must be appropriately selected to allow for
potential future changes. Ameren is not responsible for re-engineering or re-sizing of
customer's equipment.
10. Disconnects designed for vertical mounting will indicate “ON” when in the “up” position and
“OFF” when in the “down” position. When in the “ON” position, the handle shall not exceed
6 ft. 7 in. above the floor or working platform.
11. A gang operated disconnecting means shall be located on the supply side of ALL fused
service entrance equipment installations that simultaneously disconnects all ungrounded
service conductors it controls from premises wiring systems.
12. The grounded circuit conductor shall not normally be switched or be protected with an
overcurrent device. Exceptions are required for separately derived systems. All
exceptions must be approved by Ameren.
13. In accordance with the 2020 NEC Article 230.67, all dwelling units are now required to be
provided with surge protection equipment. The surge protection device (SPD) must be an
integral part of the service equipment or located immediately adjacent to the
service equipment unless it is supplied at each next level distribution equipment
downstream toward the load.
Type 1 SPD is hardwired and permanently connected, without overcurrent protection,
and located between the revenue meter and the line side of the main service
disconnect overcurrent device.
Type 2 SPD is permanently connected on the load side of the main service disconnect
overcurrent device, including SPDs located at branch panels.
Type 3 SPD is located at the point of utilization.
Type 4 SPD is part of a component assembly in listed end-use products.
Ameren does not allow customer owned Type 1 SPDs to be installed. A SPD(s) is
required to be installed when service equipment is being replaced.
14. Ground-fault protection of service equipment shall be provided for solidly grounded wye
electric services of more than 150 volts to ground but not exceeding 1000 volts
phase-to-phase for each service disconnect rated 1000 amps or greater.
15. For ungrounded service, refer to ASM Section 500 for special requirements.
Where the Ameren primary voltage (transformer high side voltage) is 12.5 kV or 13.2 kV:
• 208Y/120 volts, 4-wire, grounded-wye, limited to 1000 kVA of utility peak demand
• 480Y/277 volts, 4-wire, grounded-wye, limited to 2500 kVA of utility peak demand
Where the Ameren primary voltage (transformer high side voltage) is 34.5 kV:
• 208Y/120 volts, 4-wire, grounded-wye, limited to 750 kVA of utility peak demand
• 480Y/277 volts, 4-wire, grounded-wye, limited to 3000 kVA of utility peak demand
In all cases outlined above, the customer or their agent is responsible for reviewing the
Customer Obligations in the Warranties and Disclaimer section along with ASM Section
100.
Ameren understands that NEC load calculations will sometimes exceed the maximum size
transformer Ameren has to serve the calculated load. Ameren will work with the customer and
their agents to determine what a realistic anticipated demand will be while also allowing for
some amount of load growth.
In addition, the transformer's primary fusing must be taken into consideration for achieving
proper coordination with substation protection devices. For these reasons, Ameren requests
that Customer contact Ameren early in the Customer's design phase for any service greater
than or equal to 1600 amperes at 208Y/120 or 800 amperes at 480Y/277.
It is the Company's intent to limit the availability of these service voltage for the following reasons:
• Unequal loading of transformer coils which naturally occur with these connections and
requires the de-rating of the transformers.
• The Company's cost associated with owning and stocking 3-phase padmount
transformers at these voltages.
• Power quality issues that may occur depending on the combination of the customer's
equipment, customer loads, and distribution system loading.
• Imbalance that can occur on the Company's distribution system because of these
connection types.
For the reasons stated above, the following limitations are being placed on these non-standard
service voltages which will be offered at the Company's discretion.
• Limited to 600 amperes
• In areas where 3-phase aerial primary is available, full-delta and open-delta service from
overhead transformers may be provided. However, the customer may be required to take
a wye service.
• Open-delta service may be provided from two single-phase banked, padmount transformers
or two single-phase, banked pole mount transformers. When this may be the case and
3-phase primary become available in the future, the customer will be required to upgrade
to a wye secondary voltage if they require additional capacity. For this reason, the
customer and their electrician should choose and configure their equipment so that future
impact on the customer is minimized
• No additional 3-phase padmount transformers at these voltages will be installed. If a
transformer at an existing installation fails, service at this voltage will be maintained by the
Company. The customer may be required to upgrade to a wye secondary voltage if they
require additional capacity. For this reason, the customer and their electrician should
choose and configure their equipment so that future impact on the customer is minimized.
• The Company reserves the right to provide 3-phase services from an open-delta
installation to serve small 3-phase loads. One example would be a small lift station in a
residential area.
Again, all non-standard voltages were not, and are not available in all areas served by the Ameren
Companies. Check with local Ameren contacts to verify the service voltage and
configurations available.
A non-standard service that operates below 1000 volts as defined in ASM Section 400 may
have a grounded phase conductor used as a circuit conductor in the system.
The grounded neutral or grounded phase conductor is earth grounded at the utility transformer
and is extended to the self-contained meter socket, CT enclosure, meter disconnect, and to each
service disconnect in accordance with the latest edition of the NEC.
For underground systems, the service riser conduit(s) on the supply side of the customer's meter
disconnect, self-contained meter socket, or CT enclosure shall not contain the grounding
electrode conductor. If a customer chooses to secure / protect the grounding electrode
conductor in conduit, this conduit shall be dedicated solely for this purpose.
Customers requiring an ungrounded service for operations as permitted by the NEC shall submit
an exception request detailing the special circumstances necessitating the request. In addition,
the customer shall state in the exception request that they are aware of and accept the increased
risks of personal safety associated with an ungrounded service. Customers who receive an
ungrounded service from the Company MUST INSTALL ground-fault detection sensing
equipment on the load side of the main overcurrent protective device(s) (e.g., Erickson ground-
fault detection equipment). When supplying an ungrounded service result in an additional cost to
the Company, this may be passed on to the customer.
For electric service installations where galvanized steel RMC, aluminum RMC, or galvanized steel
EMT is used on the supply side of the main service disconnect, bonded bushings or threaded hubs
shall only be used at one end of the conduit to prevent appreciable circulating currents from flowing
on the equipment enclosures. An exception to this would be when using metallic conduit for
protection of the grounding electrode conductor. In this case, the NEC requires bonded bushings
on both ends of this metallic conduit to prevent causing a high impedance path or inductive choke.
2. The details shown in these drawings are not a substitute for an understanding of the grounding
and bonding requirements of the NEC and the requirements of the Authority Having
Jurisdiction for the area the work is taking place.
• Where other electrodes are available inside a premises, these become the grounding
electrode system and MUST NOT be connected to the driven outside electrode that
terminates within the self-contained meter socket, meter disconnect, or the CT
enclosure, EXCEPT via the grounded (neutral) conductor. This wiring method will
ensure that normal neutral currents WILL NOT flow on equipment grounding
conductors. This method is allowed by the NEC where certain conditions are met.
Reference the latest NEC 250.142(A) for use of the grounded circuit conductor for
equipment grounding.
• Where the customer has a main service disconnect within 10 feet and in sight of the
Ameren self-contained meter socket or CT enclosure, connection of an external
grounding electrode system to the main service disconnect is acceptable in lieu of
landing in the utility metering equipment.
5. Exceptions to the grounding methods found in ASM Section 500 must be approved by
Ameren Engineering prior to construction.
500.04 DRAWINGS
Figure 500-1 INTER-SYSTEM BONDING
Figure 500-2 1Ø AND 3Ø SELF-CONTAINED METERING LESS THAN 480 VOLTS
OPTION 1 - INTERIOR MAIN DISCONNECT
Figure 500-3 1Ø AND 3Ø SELF-CONTAINED METERING LESS THAN 480 VOLTS
OPTION 2 - EXTERIOR MAIN SERVICE DISCONNECT
Figure 500-4 1Ø AND 3Ø SELF-CONTAINED COLD SEQUENCE METERING
480 VOLTS (METER DISCONNECT / METER SOCKET IN
SEPARATE ENCLOSURES)
OPTION 1 - INTERIOR MAIN SERVICE DISCONNECT
Note 3 INTERIOR
MAIN SERVICE DISCONNECT
OR
MAIN DISTRIBUTION PANEL
NEUTRAL
EQUIPMENT
GROUND
NEUTRAL
Note 4
CONNECTION
BUILDING
OUTSIDE
CONNECTIO
BUILDING
N INSIDE
UTILITY
GROUND ROD
EXTERNA
GROUNDING ELECTRODE
SYSTEM
Defined in the NEC
METER
SOCKET
EXTERIOR
MAIN SERVICE DISCONNECT
OR
MAIN DISTRIBUTION PANEL
NEUTRAL
EQUIPMENT
GROUND
Note 2
NEUTRAL
Note 3
UTILITY
GROUNDING ELECTRODE
SYSTEM
DEFINED IN THE NEC
INTERIOR
MAIN SERVICE DISCONNECT
METER METER OR
DISCONNECT SOCKET MAIN DISTRIBUTION PANEL
Note 5
Note 6
EQUIPMENT
Note 5 GROUND
NEUTRAL
NEUTRAL NEUTRAL
NEUTRAL
UTILITY
CONNECTION
INSIDE
CONNECTION
GROUNDING ELECTRODE
SYSTEM
OUTSIDE
EXTERIOR
MAIN SERVICE DISCONNECT
METER OR
METER MAIN DISTRIBUTION PANEL
DISCONNECT SOCKET
Note 4
Note 5
Note 4 EQUIPMENT
GROUND
NEUTRAL
NEUTRAL NEUTRAL
NEUTRAL
UTILITY
GROUNDING ELECTRODE
SYSTEM
DEFINED IN THE NEC
INTERIOR
COLD SEQUENCE
MAIN SERVICE DISCONNECT
METER DISCONNECT/METER SOCKET OR
COMBINATION MAIN DISTRIBUTION PANEL
Note 5
EQUIPMENT
GROUND
NEUTRAL
NEUTRAL
CONNECTION
Note 4
INSIDE
NEUTRAL
UTILITY
GROUNDING ELECTRODE
CONNECTION
SYSTEM
Defined in the NEC
GROUND ROD
OUTSIDE
EXTERNAL
EXTERIOR
COLD SEQUENCE
MAIN SERVICE DISCONNECT
METER DISCONNECT / METER SOCKET OR
COMBINATION MAIN DISTRIBUTION PANEL
Note 5
EQUIPMENT
GROUND
NEUTRAL
NEUTRAL
Note 4
NEUTRAL
UTILITY
GROUNDING ELECTRODE
SYSTEM
DEFINED IN THE NEC
INTERIOR
MAIN SERVICE DISCONNECT
OR
CT, CT/PT ENCLOSURE MAIN DISTRIBUTION PANEL
Note 4
EQUIPMENT
GROUND
NEUTRAL
M
NEUTRAL
Note 3
Note 3
OUTSIDE BUILDING
CONNECTION
INSIDE BUILDING
CONNECTION
UTILITY
GROUND ROD
EXTERNAL
GROUNDING ELECTRODE
SYSTEM
DEFINED IN THE NEC
EXTERIOR
MAIN SERVICE DISCONNECT
OR
CT, CT/PT ENCLOSURE MAIN DISTRIBUTION PANEL
Note 4
EQUIPMENT
GROUND
NEUTRAL
M NEUTRAL
Note 3
Note 3
NEUTRA
UTILITY
GROUNDING ELECTRODE
SYSTEM
DEFINED IN THE NEC
SWITCHGEAR
PT
MAIN
M CT
Note 2
Note 3
NEUTRA
UTILITY
GROUNDING ELECTRODE
SYSTEM
DEFINED IN THE NEC
Where through the roof service masts are installed, the customer assumes all responsibility for roof
leaks. This mast must be constructed of galvanized steel RMC. Service masts must be of adequate
strength or be supported by braces or guy wires to safely withstand the strain imposed by the
service drop. The Attachment point must have sufficient height to meet clearance requirements
stated in ASM Section 800. The service drop is not permitted to be secured to the mast
between the weatherhead and a coupling installed above the last point where the conduit is
secured to a building or structure. Only Company owned electric overhead service drop
conductors shall be permitted to be attached to the service mast.
600.06 DRAWINGS
Figure 600-1 TYPICAL PERMANENT SERVICE DROP
Figure 600-2 MAX IMUM STANDARD SERVICE DROP ATTACHMENT TO
GALVANIZED STEEL CONDUIT MASTS
Figure 600-3 OVERHEAD SERVICE TO MULTIPLE WEATHERHEADS
Figure 600-4 CUSTOMER OWNED - TEMPORARY OVERHEAD METER POLE
INSTALLATION
Figure 600-5 CUSTOMER OWNED - PERMANENT OVERHEAD METER POLE
INSTALLATION - 100, 200, OR 320 AMPERES CONTINUOUS / 400
AMPERES MAX
Figure 600-6 OVERHEAD SERVICE CLEARANCES FOR ATTACHMENT TO
BUILDINGS (0 TO 600 VOLTS)
Figure 600-7 OVERHEAD SERVICE ATTACHED TO BUILDINGS (0 TO 600
VOLTS)
Figure 600-8 NON-STANDARD ELEVATED CT METERING (EXTERNAL POLE /
MAST MOUNTED CTs ON BIRD CAGE CTs)
Weatherhead
3
10
Wedge Clamp 4
Lag Screw into
Roof Rafters/ 6” Min
Back Plate
7 Mast Clamp
18” 5
4 12” Min
Sufficient Support
to Service Mast is
4' Max Required 2
Wedge Clamp 6” Min
Galv Riser Strap
Galv Riser Strap
11 11
Meter Socket
4” X 4” POST
6”
6
60” Max
Service Drop
Meter Socket
Service Switch
12' -0”
Min
PLAN VIEW
7'-0” 2” X 4”
Min
GROUND LEVEL
NEC Approved Ground
12”
GROUND LEVEL 10'-0"
48”
22”
8'- 0” 2” x 4”
1 3
A
Ameren service conductors
8”
12”
Connectors owned
and installed by P
Ameren
18
15
R
14
Q 20
C, D, H
B
M, P
L
54” min -
19
N
66” max
J 17
K
G
6" MIN. to 9" MAX.
6'-0” Min
8'-0” Min
1. Service drop conductors, grips and connectors are provided, installed, and owned by Ameren.
2. See ASM Figure 600-2 for maximum length of residential service drop. For all other services
contact Ameren for maximum service lengths. Reduced distance or higher attachment point
may be required for large service or to maintain minimum clearances.
3. In Missouri, service attachment hardware is provided by Ameren and installed by customer.
In Illinois, service attachment hardware with adequate strength for attachment of Ameren's
service drop conductors is provide and installed by customer.
4. Service entrance conductors to be connected to meter socket terminals by Customer.
Service entrance conductors to extend a minimum of 36 in. or longer if required by local
Authority Having Jurisdiction, outside the weatherhead for connection to service drop.
5. Service raceway and service entrance conductors to be owned, maintained, and installed by
Customer.
6. Customer's installation to meet the requirements of all applicable local codes as well as the
NEC.
7. Grounding shall meet the requirements of the latest edition of the National Electrical Code
(NEC) or the requirements of the Authority Having Jurisdiction (AHJ).
8. Insulated conduit bushings are required for raceways terminating in the meter socket.
9. The use of flexible metallic conduit, liquid tight flexible metallic conduit, or liquid tight flexible
non-metallic conduit for service riser mast is prohibited unless approved by the local
Authority Having Jurisdiction (AHJ).
10. Liquid tight flexible non-metallic conduit is permitted between the self-contained meter
socket and the main service disconnect where contoured surfaces or obstruction(s) exist.
11. Service entrance cable (type SE) is permitted for use as a riser or between the
self-contained meter socket and main service disconnect.
12. The use of electrical grade schedule 40 or 80 PVC conduit for service mast, if it is not
supporting service drop is allowed unless prohibited by the local Authority Having
Jurisdiction (AHJ).
13. Customer to provide and install support for service attachment and meter socket.
14. Refer to ASM Section 800 for required clearances.
15. When conductor tension exceeds the holding capacity of the pole, customer is required to
install down guy and anchor of sufficient strength, and guy lead length to be same as
service attachment height.
16. If customer installs a yard light on this pole, such yard light shall maintain a clearance to
Ameren service conductors of not less than 24 in.
17. Meter pole provided by customer must have a tag or brand stating pole height, pole class
and type of treatment at 6 ft above embedded depth.
18. Riser mast clamp must be within 6” of weatherhead.
19. When a meter base is over walkways less than 36 in. wide or in areas where flooding occurs,
the center of the meter glass can be 78 in. above walking surface.
20. Riser mast clamps must be 30 in. or less apart.
10'- 0”
36” 36” 36”
36”
36” 36” 36”
12'-
18'-
12'
4 COURSE
MINIMUM
F
F
E
D
4 COURSE
A
MINIMUM
1. The customer will provide and install the meter socket(s) or enclosure(s) and the line-side
riser conduit(s) of Schedule 80 electrical grade PVC. This line conduit(s) shall extend from
the meter socket(s) to a minimum of 18 in. below the groundline for a continuous conduit
system or 24 in. for direct burial.
2. The customer provided conduit described in the previous item shall include a PVC male
adapter, lock nut, and insulated bushing at the meter socket. If the required expansion
coupling includes a male adapter end, only the lock nut and insulated bushing are required.
At the below grade end of the conduit, a PVC male adapter and insulated bushing, or PVC
coupling, or PVC end bell shall be installed to protect the direct buried conductor. If local
authorities require rigid metal service conduits, then bonded bushings are required. Refer
to ASM Section 500 for metallic conduit bonding requirements.
3. Protection from mechanical damage and future access shall be provided and installed by
customer for conductor under paved surfaces such as public or private driveways,
roadways, streets, alleys, sidewalks, patios, etc. by installation of conduit at a minimum
depth of 24 in.
4. Underground service conductors are not permitted beneath a pool, spa, or hot tub nor are
underground service conductors allowed in the area extending 5 ft horizontally from the
inside wall of a pool, spa, or hot tub.
Where underground service conductors exist and a customer desire to install a new pool,
spa, or hot tub, it is the customer / installer's responsibility to locate the pool, spa, or hot
tub in adherence with the requirements above. This may require Ameren to relocate the
underground service at the customer / installer's expense.
5. The conductor route must be cleared of all obstructions, both above and below grade, and
within 6 in. of final grade for Company installations.
6. Customer must mark all customer owned buried facilities on their property prior to Ameren
arriving on site to install underground facilities. If customer fails to mark buried facilities and
damage occurs during installation of Company facilities, repairs will be made by the
customer at no cost to the Company. Direct buried conductor(s) shall have a minimum
burial depth of 24 in.
7. The maximum service length shall be determined by the Company. It is the customers'
responsibility to secure information from the Company pertaining to allowable lengths for
service installations.
8. In Illinois, Company will install, own, and maintain service conductors for one or two
residential dwelling units on a single deeded lot. For three or more residential dwelling units
on a single deeded lot, it is the customer's responsibility to install, own, and maintain
service conductors. For locations where dwellings are constructed with zero lot line
construction (e.g., a shared common wall, but separated deeds), the Company will install,
own, and maintain the service conductor to each dwelling unit. If three or more service
installations are grouped together in an assembly for zero lot line construction, the service
conductors will be owned, installed, and maintained by the customers.
B. Continuous Conduit (Missouri - REQUIRED, Illinois - OPTIONAL)
1. The customer will provide and install the meter socket(s) or enclosure(s) and line-side riser
conduit(s) of Schedule 80 electrical grade PVC. This conduit(s) shall include a PVC male
adapter, lock nut, and insulated bushing at the meter socket(s). If the required expansion
coupling includes a male insulated metal (or PVC) adapter end, only the lock nut and
insulated metal (or PVC) bushing are required. The bottom lower left knockout of the meter
socket is intended for Ameren's underground supply service conductors. All conduit
sections shall be securely fastened together using standard grade cement. Refer to ASM
Figure 700-9 for customer owned and installed service conduit drainage at meter or pole
if required.
2. The service riser conduit to the meter socket shall include an expansion coupling that
allows for 12 in. fall for 2-1/2 in. conduit and 8 in. fall for 3 in. conduit.
3. Customer installed conduit shall be installed along the shortest route, and the number of
bends (sweeps) shall be kept to a minimum. There shall be a maximum of 3 - 90o, 36 in.
radius bends (sweeps) for 2-1/2 in. conduit or 3 in. conduit installations. 24 in. radius bends
(sweeps) are permitted where rock or foundation problems exist.
4. All sections shall be securely fastened together using standard grade cement.
5. Minimum burial depth in trenchable earth is 24 in. In rock or untrenchable soil, this depth
may be reduced to 12 in. if service conductor is installed in Schedule 80 PVC conduit or
encased in concrete. Depths of less than 12 in. are not permitted.
6. If it is not possible to achieve uniformity in the trench bottom it must be over-excavated 4 in.
to 6 in. and the bottom refilled with good quality properly compacted bedding material.
Approved materials: Sand, limestone screenings, concrete slurry, or concrete.
9. Customer shall provide, install, and secure at each end a polyester pulling tape of 2500
lb. capacity when access inside Ameren equipment is not needed. Pulling tape must be
extended a minimum of 10 ft. beyond each end of the conduit system. Ameren personnel
will be responsible for providing and installing the pulling tape when access inside
Ameren equipment is required to complete installation.
10. In Illinois, Company will install, own, and maintain service conductors for one or two
residential dwelling units on a single deeded lot. For three or more residential dwelling
units on a single deeded lot, it is the customer's responsibility to install, own, and maintain
service conductors. In cases where a developer has a single deeded parcel that contains
multiple dwelling structures (e.g., multiple structures that may be single or multiple
dwelling occupancies), it is the developer's responsibility to install, own, and maintain all
service conductors. For locations where dwellings are constructed with zero lot line
construction (e.g., a shared common wall, but separated deeds), the Company will
install, own, and maintain the service conductors. If three or more service installations are
grouped together in an assembly for zero lot line construction, the service conductors will
be owned, installed, and maintained by the customers.
11. In Missouri, Company owns, installs, and maintains the residential service conductors if
the customer installs a complete conduit system. Customer has option to not install a
conduit system, but in this case, they must own / install / maintain the service
conductors. If the customer wants to install the service installation at a location farther
than allowed by Ameren, this option is allowed if the customer installs, owns and
maintains the service conductor for either direct buried or conduit system installation.
3. For secondary voltage conductor owned by Ameren, the burial depth to the top of the
conduit shall be no less than 24 in. For customer-owned service conductor, the burial depth
to the top of the conduit shall be no less than 18 in. (24 in. If under paved roadways, alleys,
driveways, parking lots, etc.) per the latest edition of NEC Article 300.5.
4. For primary voltage, 36 in. minimum burial depth, 36 in. minimum radius bends (sweep).
B. Service from a pole
Customer shall furnish, own, and maintain the materials for the service to the Company's
pole and provide sufficient access space for the purpose of installing or changing Company
equipment.
1. Customer shall furnish, own, and maintain all the materials for the service to the
Company's conductors.
2. The customer shall install their facilities to the quadrant of the pole designated by the
Company.
3. For a continuous conduit installation, the customer shall extend the facilities to the pole and
include a 90-degree schedule 80 conduit bend (sweep) at the base of the pole at a
Company designated location.
4. In Illinois, Customer shall furnish a 10 ft section of schedule 80 PVC (per riser) of
appropriate size, the remaining section of schedule 40 PVC of appropriate size coupling(s),
adapter(s), and weatherhead(s) for attachment to the riser pole and supply sufficient
conductor to reach the Company's secondary transformer bushings or secondary
conductors.
5. In Missouri, Company furnishes all conduits, coupling, and adapters for attachment to the
riser pole.
6. Any conduits on a pole will require standoff brackets, supplied by Ameren.
7. Installation of facilities on the Company pole must be coordinated with local Company
personnel. Company will make final connections.
C. Service from a padmount transformer
1. Customer shall furnish, own, and maintain all the materials for the service to the Company's
padmount transformer and provide sufficient space for transformers, switches, and related
equipment adjacent to paved surfaces intended for normal vehicular traffic or parking for
the purpose of installing or changing Company equipment.
2. The customer must provide adequate length of service conductors for connection to the
transformer secondary bushings, typically 6 ft above the transformer pad.
3. In Illinois, excavate to 18 in. from the face of existing padmount transformers. Coordination
with the Company is required to arrange for Company to complete the trenching and
installation of customer provided conduit and bend(s) (sweeps). For proposed new
transformer installations, the customer is required to excavate to a point
designated by Company and install all conduit, bend(s) (sweeps), and customer
furnished service conductors. Customer is also required to backfill, level, and properly
tamp the location for the new transformer installation. Bends (sweeps) should extend
approximately 6 in. above the surface and have a protective bushing to smooth the
conduit edge. Metallic conduit and / or metallic bends (sweeps) are not allowed in
transformers, pedestals, or switch cabinets unless required by the local AHJ. Refer
to ASM Section 500 for metallic conduit bonding requirements.
4. In Missouri, for single phase padmount transformers rated 120/240 volts or three phase
padmount transformers rated 208Y/120 volts:
Customer will install conduit and conductor into the secondary voltage side of
transformer, and ONLY approved and licensed electrical contractors are allowed to
perform this work.
Contact the Ameren Missouri Customer Service Department at 800-552-7583 within
the St. Louis Metropolitan area to arrange for Ameren Missouri to open the transformer
and to cover the primary and secondary voltage connection points and conductors for
safety purposes.
Ameren Missouri will not allow the electrical contractor to install conduit into a live front
transformer (the primary voltage connections are exposed). Live front transformers will
either:
a.) Be replaced by Company prior to an electrical contractor installing conduit or
b.) Electrical contractor to terminate conduit 18 in. from edge of transformer pad.
Contact Ameren Missouri for coordination.
The electrical contractor is required to coordinate with the Company to arrange for
Company to complete the trenching and installation of customer provided conduit,
bend, and conductor.
5. In Missouri for three phase energized transformers rated 480Y/277 volts, electrical
contractor to terminate conduit 18 in. from the edge of the transformer pad. Contact
Ameren Missouri for coordination.
The electrical contractor is required to coordinate with the Company to arrange for
Company to complete the trenching and installation of customer provided conduit, bend
(sweep) and conductor.
4. In Illinois, the structure supporting the meter installation shall be located within 15 ft. of, but
no closer than 5 ft. to the Company's designated point of service.
5. In Missouri, if Customer temporary service is installed per ASM Figure 700-14A &14B,
the meter structure shall not exceed 6 ft. but be no less than 3 ft. from the Company
padmount transformer or secondary pedestal.
700.05 DRAWINGS
Figure 700-1 SINGLE SERVICE INSTALLATION: RESIDENTIAL / NON-
RESIDENTIAL (SINGLE PHASE 200 AMP)
Figure 700-2 SINGLE SERVICE INSTALLATION: RESIDENTIAL / NON-
RESIDENTIAL (SINGLE PHASE 320 AMP CONTINUOUS /
400 AMP MAX)
Figure 700-3 MULTIPLE SERVICE INSTALLATIONS FOR 2 TO 6 METERS
SINGLE PHASE ONLY
Figure 700-4 TYPICAL VERTICAL GANGED METER STACK:
UNDERGROUND SERVICE 4, 5, OR 7 TERMINAL METER
SOCKET; ONE OR TWO MAIN SERVICE DISCONNECT(S)
Figure 700-5 AMEREN SERVICE CONDUCTOR - CONTINUOUS SERVICE
CONDUIT INSTALLATION: RESIDENTIAL CUSTOMERS -
ILLINOIS ONLY
Figure 700-6 CUSTOMER OWNED AND INSTALLED SERVICE
CONDUIT: RESIDENTIAL SUBDIVISION -
MISSOURI ONLY
Figure 700-7 CUSTOMER OWNED AND INSTALLED, DIRECT BURIED
SERVICE CONDUCTOR; CONNECTION TO PEDESTAL,
PADMOUNT TRANSFORMER, OR POLE: NON-RESIDENTIAL -
ILLINOIS ONLY
Figure 700-8A CUSTOMER OWNED AND INSTALLED SERVICE
CONDUCTOR & CONTINUOUS CONDUIT SYSTEM:
CONNECTION AT POLE - NON-RESIDENTIAL
Figure 700-8B CUSTOMER OWNED AND INSTALLED SERVICE
CONDUCTOR IN CONTINUOUS CONDUIT SYSTEM:
CONNECTION AT PEDESTAL, PADMOUNT
TRANSFORMER FOR ALL VOLTAGES: NON-
RESIDENTIAL
Figure 700-9 CUSTOMER OWNED AND INSTALLED SERVICE CONDUIT
DRAINAGE AT METER OR POLE IF REQUIRED
Figure 700-10 CUSTOMER PROVIDED METER STRUCTURE FOR SINGLE POSITION
SELF-CONTAINED METER / MAIN DISCONNECT(S)
Wall Stud
Detail “AA” Detail “BB”
B, C
Screw Into Studs
6” 6”
G,H
9
16” 16”
2 x 4 Studs
C
1 5 4
LOAD
LINE
I
Grade
6 8
1. See ASM Section 200 for mounting height, approved locations, and requirements for
mechanical protection.
2. All materials except the supply conductors shall be furnished, installed, and connected by
customer.
3. The meter socket shall be secured to solid wood and use #14 x 3 in. wood screws or
stainless-steel screws. In brick, use expansion shields and lag screws. No drywall screws
accepted.
4. The conduit hanger shall be securely fastened, preferably by a lag screw into the floor joist. If
attached to the foundation, a lead expansion shield shall be used. An alternative to the
expansion shield is a stud shot into the foundation.
5. An expansion coupling is only required for a continuous conduit system, where bend (sweeps)
is buried below the meter socket, and where the riser conduit emerges from grade through a
concrete slab that does not have an oversized hole (e.g., concrete not adhered to riser). The
expansion coupling should be installed with the outer sleeve fitted into the meter socket with
the inner sleeve positioned at the manufacturer's midway mark.
6. The area underneath the bend (sweep) shall consist of good quality fill material and dirt free of
debris. The area shall be compacted around the foundation wall. Acceptable fill materials:
sand, limestone screenings, or concrete slurry, concrete.
8. For services 200 amperes and less, 2-1/2 in. electrical grade PVC conduit, expansion
coupling, bends (sweeps), and connectors shall be used. Minimum bend (sweep) radius of 36
in. is required, but a 24 in. radius bend (sweep) is permitted where rock or foundation problems
exist.
9. Ameren installed supply service conductor and Customer owned supply service conductor will
only enter through the bottom left-hand knockout. No load side meter wiring is permitted on the
left-hand side of the enclosure where the conduit that would contain Ameren's / Customer's
supply service conductor enters the enclosure. The area must be kept clear to permit
installation and potential replacement of supply service conductor and to eliminate the
possibility of premature failure due to conductors coming in contact with each other. If improper
wiring is performed, the supply service conductor will NOT be installed by Ameren.
10. Customer owned and installed service conduit drainage at meter or pole if required, refer to
ASM Figure 700-9.
A
Grade
3
Detail “AA”
I
6” 6”
G,H 11
10 11
16” 16”
2 x 4 Studs
C
1 5 4
D,E,F 6 LOAD
LINE LOAD 10 LINE LOAD 10
10
10 5 12
6B 12
Detail “BB” 12
5
8
12 7 7
I
Grade
6” MIN. TO ANY
OBSTRUCTION
C 7
LOAD
1 E, F, G LOAD
LINE
GRADE
24"
SUPPLY
SERVICE CONDUCTOR
H
SERVICE EQUIPMENT
10
9
9
5 7
6” MAX.
E 13
6” spacing between
Pole and conduit
4 5 H
COMPANY PEDESTAL
OR TRANSFORMER A 13 C
8' Min to
Lowest G
Bracket
18” A
6”
3
24" B
Min
I
D E D
E
6
4 5 E
Secondary Pedestal or
Padmount Transformer
8' Min to C
48” Lowest F
48” Bracket A
G 12 A
6”
6” Max 3
24" Min
I B J B
4. See ASM Figure 700-1 for required meter socket and riser attachment.
Company
Pole
Company 2 3 B
Transformer
Company
Pedestal M, N, O, P, Q
8' Min to A
A7 8
18” 18” Lowest Driveway 4
Bracket
18" 6
12” 12”
24”
1 8 L
2. Refer to ASM Figure 700-1 for required meter socket and riser attachment.
3. Refer to ASM Section 200 for meter socket mounting height.
4. Approved bonding / grounding as required by local inspection authority or latest version of NEC.
Refer to ASM Section 500.
5. If Ameren equipment is not in place, the location where it will be installed shall be obtained from
Company representative before conduit installation.
6. End of riser conduit at side of home / pole should be buried 18” minimum depth.
10
6” 6
11
5
E
J
4
F
C
A
8' Min to
Lowest Pulling
Bracket A
Tape
6” Max
13 1
13 J
2
B
7 B
3
7
3
5 6
E
Company provided
Transformer or Pedestal C
I 4 A
13 12
2
K 7
3 J 3 B
FINAL GRADE
BUILDING OR
POLE LOCATION
2 ½” or 3” CONDUIT BEND
36” RADIUS. 90DEGREES
Note 3 2
4”
12”
2 ½” or 3” CONDUIT COUPLING
SCH. 80 PVC
APPROX 18”
¾” GRAVEL WIDE BY
2' - 6” LONG
Meter Socket
(Section 1100)
10
6” min. to
Provide Cap any 6” min. to
or Fill Post obstruction any
with Concrete obstruction
9
Conduit bushing
required
for mechanical
protection of conductor
C
Main Breaker
5
A Customer Conductor
54” to 66”
center of 2” Min Galv
13 Steel RMC 13 C
the meter E
Ameren Service
glass conductor 7
D
6” 6”
Ground Line
Ground Line
3'-0” min. Concrete
Concrete foundation to be 3 x pipe OD
12
but in no case less than 12”
8'-0"
With top of concrete foundation sloped up
Mounting Structure to shed water
12” min.
10
11
Metering
Transformer
X
Enclosure
7'-0”
PT
enclosure 54” Min.
66” Max.
10
Attach Strut Channel to the Galv
Steel (RMC) with Min 3/8”-16
Galv Steel U-Bolts
12”
CUSTOMER OWNED
LIGHT STANDARD
AMEREN
PADMOUNT TRANSFORMER
OR PEDESTAL
1 2 3
CUSTOMER CONDUCTORS
& CONDUIT
4” X 4” POST
CUSTOMER'S
SERVICE
GROUND WIRE EQUIPMENT
METER
METER SOCKET
METER SOCKET
54” Min
66” Max
AMEREN PADMOUNT
TRANSFORMER
OR PEDESTAL 120/240 V-3 WIRE
2
SINGLE SINGLE PHASE
PHASE
120/240v
3-WIRE
18"
2' 0”
NEC APPROVED
GROUNDING METHOD
1. Customer's service equipment may be mounted below meter socket, but center of meter
socket must be mounted at 54 in. min to 66 in. max above grade. See NEC for GFCI
protection.
2. Customer to install 3 wire direct burial conductor from meter base to this point & leave sufficient
(8 ft.) length for Ameren to connect to pedestal or transformer.
3. Meter, pedestal, or padmount transformer are provided by Ameren. All other material to be
furnished and installed by customer. Refer to BuildWithAmeren.com for meter socket
requirement.
4. Final connection to be completed by Ameren.
4” X 4” POST
CUSTOMER'S
SERVICE
EQUIPMENT
GROUND WIRE
METER
3
54” Min 66”
Max A 4
AMEREN PADMOUNT
TRANSFORMER
OR PEDESTAL 120/240 V-3 WIRE
SINGLE SINGLE PHASE
PHASE
120/240V
3-WIRE
'
D, E
A 3
4
48”
8' 0”
E C
J
H D
I
F F A
B
36" min
Terminate PVC 6”
Above final grade
Final grade 11
- 30" Min
18”
COVER
32”-36”
2 1
Post extension
2
2
12
36" Min
2
36" Min
32”-36”
2. For Missouri Only, underground fed residential service installations on the side of a
single-family dwelling unit are allowed to be at 36 in. min to the center of the meter
glass.
3. When a service installation consists of a meter pedestal, the center of the meter glass
must be 36 in. or greater.
9. A roof is considered accessible to pedestrians if there is a means of access through a
doorway, ramp, stairway, or permanently mounted ladder.
10. Clearances of Services over Swimming Areas or Hut Tub:
Although it is possible to have overhead services cross a swimming pool or hot tub, this
practice is highly discouraged. It is necessary that the maximum conductor sag under
various operating and environmental conditions be determined. Contact your local Ameren
representative for assistance.
30" E
47" D A D
30" 42" 30" B
FRONT FRONT
Window
Window or
Ventilation Duct
Door of transformer
5' should not face
9' building or structure.
Transformer
F F F F
E E
F F G
E A
A G
D D D D
D D G
B B B
A
G G
H G
DOOR SIDE
E
CAUTION: Installation of barrier rails must be coordinated with electric conduit installation
to avoid mutual interference.
2. Construct the pipe barriers as follows:
A. Use 8-1/2 ft. sticks of steel pipe.
B. Drill holes with an 8 in. auger.
C. Bury 56 in. of pipe leaving 46 in. of pipe exposed above grade.
D. Fill the hole around the pipe with concrete to the top of grade.
E. Fill the pipe with concrete.
F. Paint the pipe with yellow lacquer.
G. Round over concrete creating a dome on the top of each post.
3B
3B
When an imbalance occurs, the Company may assist customers to determine the cause of the
problem and may recommend corrective measures.
900.05 POWER FACTOR
Acceptable power factor is defined by the appropriate Company tariffs. The Company's Customer
Service Representative will provide Customers with appropriate information upon request.
Customers may install the corrective equipment necessary to meet this requirement on customer's
side of Company meter. Such equipment shall be controlled and maintained by Customer to
avoid a leading power factor at any time, and to avoid high voltage conditions during periods of
light load. To monitor this power factor requirement, the Company will install appropriate
metering equipment for the monthly billing of a KVAR reactive charge as applicable.
For all customers receiving service under other rate schedules, not voluntarily complying with this
power factor requirement, the Company may, where practical, install corrective equipment on its
side of the meter and charge customer a lump sum amount for the current cost of such equipment
and the cost of any subsequent additions to or replacement of such equipment whenever said
future installations occur. Failure of Customer to install such corrective equipment or to pay for that
installed by the Company currently, or in the future, may be grounds for the disconnection of
electric service.
900.06 CAPACITORS
Use of capacitors may become necessary for a customer to achieve acceptable power factor
correction. In every case where the customer elects to install capacitors, the Company must be
consulted prior to purchase or installation. Improper size, type, installation, or operation of
capacitors can have a serious adverse effect on the Company's service to other customers. It may
also pose a danger to personnel working on the Company's distribution lines. When a customer
installs capacitors on their electrical facilities to improve the power factor of their installation, the
customer shall provide, at the request of the Company, to avoid abnormal voltages or damage
to the Company's facilities, a means of automatically disconnecting any or all the capacitors
when the equipment causing the low power factor is not operating.
900.07 PROTECTIVE EQUIPMENT
Customers are advised to install protective equipment in accordance with the latest edition of the
National Electrical Code or other pertinent sources of information for all types of equipment such
as, but not limited to, motors, computers, or any other type of voltage sensitive electronic
equipment. Adequate protection should be provided for the following conditions:
A. Overload.
B. Loss of voltage.
C. High or low voltage.
D. Loss of phase (single phase condition on three phase motors and transformers).
E. Re-establishment of normal service after any of the above.
F. Phase reversal.
G. Motors that cannot be subject to full torque on start-up.
H. Harmonics or waves form irregularities.
I. Transient voltage spikes because of lightning, capacitor switching, and routine circuit
switching.
Sensitive equipment such as Variable Frequency Drives at a customer's facility may require
additional protection in the form of a choke (reactor) for both the AC supply and DC output to
prevent the VFD from nuisance tripping or failure from a high voltage transient event.
The lack of adequate protection may result in damage to customer equipment and the associated
expense of delay and repair. The Company will not be responsible for loss or damage to
customer-owned equipment where such loss or damage is caused by the absence of protective
devices, inadequate protective devices, or failure due to not following manufacturer and utility
recommendations.
All motors and special apparatuses should be equipped with suitable undervoltage time delay
tripping devices to protect against sustained undervoltage or service interruption and to
prevent automatic disconnection of equipment upon momentary voltage disturbance.
Three phase motors should be equipped with suitable protective devices to prevent single
phase operation, improper direction of rotation, and excessive heating due to overcurrent or
voltage unbalance.
B. Three-phase Transformations
Three phase transformers on the load side of Main Disconnecting Means should be equipped
with suitable protective devices to prevent the Loss of Phase condition.
Customers must carefully evaluate the operational characteristics of transformers located on
the load side of Main Disconnecting Means. Many step up / step down transformer
manufacturers use a standard three-legged core design. On a grounded-wye system, the Wye
/ Wye-grounded construction reduces the likelihood of ferroresonance and provides a ground
source. However, under the loss of phase condition (unbalanced voltage) or unbalanced load,
this can create zero sequence voltage (zero sequence flux in the core). In the three-legged
construction, there is no path for this flux to circulate within the core. Thus, the flux jumps
through the tank and air gap. Flux through the transformer tank (enclosure) creates localized
eddy current heating so much as to discolor / overheat the unit and possibly leading to failure.
It is highly recommended to incorporate one of the following transformer options to help
mitigate the conditions:
1. One side of the transformation being Delta connected.
2. A delta tertiary connection associated with the Wye / Wye Configuration.
3. Three individual single-phase transformers connected to form a three-phase bank or
triplex construction.
4. A four- or five-legged core.
5. Shell type core construction.
6. A three-legged transformer with primary protective devices that sense loss of voltage
magnitude and unbalance. When excessive voltage unbalance is detected, all
primary phases need to be disconnected simultaneously.
If this voltage transformation is associated with a DER installation (solar / energy storage /
wind) that utilizes inverters, a Wye / Wye configuration with a Delta connected tertiary
winding may prevent the inverter from sensing a Loss of Phase event on a three-phase
system. The consequence of not detecting the Loss of Phase condition would be a
violation of Standard IEEE 1547. Compliance with IEEE 1547 is required by Ameren
Illinois and Ameren Missouri for all customer with DER interconnections.
Company will not be responsible in any way for damage to Customer equipment due to failure
of Customer to provide adequate protection.
Customers may need to install power quality equipment to between the main service
disconnect and their equipment to mitigate any equipment damage and to maintain
electric supply to critical loads. The power quality equipment may be generators,
uninterruptible power supplies (UPS), surge suppressors or other devices. These devices
will not be purchased or provided by Ameren.
B. Meter sockets 320 amperes continuous / 400 amperes max rated shall be equipped with
mechanical pressure, stud type connectors that are tinned and suitable for either
aluminum or copper conductors.
8. Multi-position (trough / gang) types of self-contained metering equipment with direct upward
termination of underground supply conductors (without a conductor loop to terminate supply
side conductors) are acceptable provided they allow for conductors to be trained in a manner
that would prevent ground settling and frost heaving from placing tension on supply conductors
that would transfer to the terminal box supply termination lugs.
9. Center-tap, grounded delta, 3-phase 4-wire meter sockets require the high leg / wild leg to
be placed in the right position at the meter socket and this conductor will be marked orange
in color. The high leg (also referred to as the wild leg) will terminate in the middle position on
the customer main service disconnect, except in panel boards, switchgear arrangement
ahead of and beyond metering equipment compartments.
10. For 3-phase, 3-wire corner grounded and floating (ungrounded) delta services, the unmetered
phase will be in the center position of the self-contained meter socket. For any exception to
this requirement, the field metering supervisor and the field supervising engineer must be
consulted.
11. Neutral conductor shall be marked with white or gray at all termination points such as at the
weatherhead, meter socket and main service disconnect or with other designation from
manufacture of conductor.
12. The 5th jaw on clamp jaw lever bypass sockets shall be located as shown in ASM Figure 1000-1
to ASM Figure 1000-10.
13. The meter socket must be bonded / grounded per NEC requirements. Refer to ASM Section
500.
14. Clamp-jaw lever type bypass meter sockets shall be provided with a clear polycarbonate
safety shield over the socket interior.
16. Ameren, by testing or approving equipment, gives no warranty, expressed or implied, as to the
adequacy, safety, or other characteristics of any equipment, wiring or device and assumes
no responsibility with respect thereto.
17. All unused openings in the socket shall be closed with plugs and securely tightened from the
inside.
18. Specific downtown this areas of Bloomington, Champaign, Decatur, Galesburg, Normal,
Ottawa, Peoria, and St. Louis are designated as heavy underground, grid networks, and / or
spot networks. Service restrictions are specific to their corresponding area and Customer
should consult Company to determine the voltage and method of supply that will be available
prior to beginning customer engineering or purchasing of equipment. Refer to ASM Section
1350 for more details in Illinois.
19. For Ameren Missouri, the Downtown St. Louis Underground District is the area bounded by
Twenty-Second Street, Cole Street, Spruce Street, and the Mississippi River, and is
designated as heavy underground, grid networks, and / or spot networks. Service
restrictions are specific to their corresponding area and Customer should consult Company
to determine the voltage and method of supply that will be available prior to beginning
customer engineering or purchasing of equipment, refer to ASM Section 1300.
20. Minimum dimension requirement for self-contained meter sockets - UG services.
120/208V
1PH-3W (Network),
120/240*,
240/480V
200 AMP 200 AMP MAX 3PH-3W 240V, 480V 12-3/4” x 19” x 4-7/8” 9” Lever*
208Y/120V,
3PH-4W 240/120V,
480Y/277V
1PH-3W 120/240V
15” x 31-1/2” x 4-7/8” 17-1/2” Lever
320 AMP 400 AMP MAX 3PH-3W 240V
3PH-4W 208Y/120V 17-3/4” x 38-3/4” x 6-1/2” 19-1/4” Lever
*Lever Bypass not required for TEMPORARY 200 AMP 1PH - 3W 120/240V service. For 201 amp
and greater, lever bypass is required. Refer to ASM Section 1000.03.
Table 1000-2 UG Service Self-Contained Meter Socket with Load-Side Breaker (METER / MAIN COMBO)
120/208V
1PH-3W (Network), 14” x 34-1/2” x 4-1/2” 9”
200 AMP
200 AMP 120/240
MAX Lever
208Y/120V,
3PH-4W 17-1/4” x 34” x 5-3/4” 10-3/4”
240/120V
15” x 42” x 4-7/8” (Vertical)
1PH-3W 120/240V
400 AMP 29” x 35” x 6” (Horizontal)
320 AMP 17-1/2” Lever
MAX 15” x 42” x 4-7/8” (Vertical)
208Y/120V,
3PH-4W
240/120V 29” x 35” x 6” (Horizontal)
1. Clamp-jaw lever bypass self-contained meter sockets are required in the following individual
meter socket applications:
A. Residential single phase (100 - 320 amperes continuous / 400 amperes max)
B. Non-residential single phase (100 - 320 amperes continuous / 400 amperes max)
C. All three phase services (100 - 320 amperes continuous / 400 amperes max)
D. All self-contained single phase and three phase 480 volts services (200 amperes max)
F. Single meter socket lever bypass handle to be 1 - ¾ in. minimum from side of enclosure.
For gang metering, the lever bypass handle to be ¾ in. minimum from side of enclosure.
2. Clamp-jaw lever bypass meter socket is required for all multi-meter sockets for residential and
non-residential services with or without a main service disconnect. A slide type bypass is not
permitted.
3. For a single-phase 100 or 200 amperes temporary service installation, a clamp-jaw lever
bypass or horn bypass is not required in the meter socket. If that meter socket is to be reused
for the permanent service, a clamp-jaw lever bypass will be required.
The clamp-jaw lever bypass meter socket shall be heavy duty, lever operated, clamp-jaw
with jaw tension release design with plastic protective shield like the Milbank (HD-5 or HD-7)
or Siemens / Talon (HQ-5 or HQ-7) bypass mechanisms. The bypass action of all lever type
bypass mechanisms shall be visible. This includes the ability to visibly see the opening and
closing of the bypass mechanism contacts, as well as the clamping action of the meter socket
jaws. Bypass mechanisms not meeting this requirement shall be rejected. Clamp-jaw lever
bypass mechanisms not previously used on the Ameren system shall be presented to the
Standards Engineering Department for review.
1. Multi-meter socket installations shall conform to the same clamp jaw lever bypass criteria in
ASM Section 1000.03 above.
2. Combination multi-meter equipment installations with fused or circuit breaker type main
service disconnects not listed in the Ameren Approved Metering Equipment List may be
acceptable subject to Company approval of meter sockets, location, electrical one line,
conductor landing space, security provisions, etc., before fabrication is started. Metering
equipment not found on the Ameren Approved Metering Equipment List must secure approval
from Ameren Metering and the Ameren Standards Department before ordering of the
equipment to avoid costly delays.
3. Multi-meter equipment requires the line side terminal compartment to have a seal-able and
padlockable cover separate from meter socket covers.
4. Up to and including six meters may be supplied at a single point of delivery without a main
service disconnect on the line side of individual meter sockets.
Where customer main service disconnects and / or fuses are combined with meter equipment,
the cover for the meter and the cover for customer access to the switch / fuse and load side wiring
shall be separated such that Company's meter and line side service compartments may be
secured and sealed separately from customer side. On such combination units, internal barriers
shall be permanently installed to prevent access to meters, equipment, and un-metered wiring via
the customer compartments. Labels should be adhered to the outside of lids (covers) on meter /
main combos stating, “Main Service Disconnect”.
It is the responsibility of Customer / Building Owner to maintain, repair and replace the metering
(socket) equipment to keep such equipment in a safe, secure, and usable condition. When such
equipment is subject to vandalism or damage, it is the responsibility of the Customer / Building
Owner to remedy the situation by protective measures or by changing location.
Ameren may perform emergency repair to maintain or restore service and to protect public safety.
If the hazard posed by the equipment is critical to safe operation, immediate disconnection of
service may be necessary until corrections are made by the Customer / Building Owner.
Ameren will notify Customer / Building Owner and the inspection Authority when an unsafe
meter socket and / or service equipment problem is found.
Ameren may allow a reasonable time, normally not to exceed 30 days, for the repair or
replacement of meter socket equipment, subject to the hazard involved. Time frame for completion
of corrections is based on severity of equipment condition. Equipment posing a grave hazard to
the public may warrant immediate disconnection.
Ameren emphasizes the need for the responsible building owner to minimize safety hazards to all
concerned by maintaining service installations which include service riser, meter socket, CT / PT
enclosure, main service disconnects, and switchboard in a safe and good working order.
1000.07 DRAWINGS
Figure 1000-1 FOR TEMPORARY SERVICES ONLY: 3-WIRE, 120/240 VOLTS, 1-PH,
SELF-CONTAINED
Figure 1000-2 3-WIRE, 120V/240 VOLTS, 1-PH, SELF-CONTAINED (LIMITED TO 320
AMPERES CONTINUOUS / 400AMPERES MAX)
Figure 1000-3 3-WIRE, 240/480 VOLTS, 1-PH, SELF-CONTAINED "NETWORK
METERING" (LIMITED TO 200 AMPERES)
Figure 1000-4 3-WIRE, 120/208 VOLTS, GROUNDED NEUTRAL, SELF-CONTAINED
(LIMITED TO 200 AMPERES)
Figure 1000-5 4-WIRE, 208Y/120 VOLTS, GROUNDED WYE, 3-PH, SELF-CONTAINED
(LIMITED TO 320 AMPERES CONTINUOUS / 400 AMPERES MAX)
Figure 1000-6 4-WIRE, 240/120 VOLTS, GROUNDED CENTER TAPPED DELTA, 3-PH,
SELF-CONTAINED (LIMITED TO 320 AMPERES CONTINUOUS / 400
AMPERES MAX)
Figure 1000-7 4-WIRE, 480Y/277 VOLTS, GROUNDED WYE, 3-PH, SELF-CONTAINED
(LIMITED TO 200 AMPERES)
Figure 1000-8 3-WIRE, 240 VOLTS, 3-PH, SELF-CONTAINED (CORNER
GROUNDED) (LIMITED TO 320 AMPERES CONTINUOUS / 400
AMPERES MAX)
Figure 1000-9 3-WIRE, 480 VOLTS, 3-PH, SELF-CONTAINED (CORNER GROUNDED)
(LIMITED TO 200 AMPERES)
Figure 1000-10 3-WIRE, 240 VOLTS, 3-PH, SELF-CONTAINED (UN-GROUNDED)
(LIMITED TO 320 AMPERES CONTINUOUS / 400 AMPERES
MAX)
Figure 1000-11 3-WIRE, 480 VOLTS, THREE-PHASE SELF-CONTAINED
(UN-GROUNDED) (LIMITED TO 200 AMPERES)
NEUTRAL
240V
120 V 120 V
120 V 240 V
NEUTRAL
120 V
1. 5th jaw may be found in 9 o'clock position, BUT not utilized for this service voltage.
240 V
Note 2
1. 5th jaw may be found in 9 o'clock position, BUT not utilized for this service voltage.
2. Knife blade switch without overcurrent protection fulfilling cold sequence meter disconnect
requirement on source side of meter socket.
3. Limit to 200 Amperes - for exception see ASM Section 200.
208 V
NEUTRAL
120 V 120 V
1. 5th jaw must be in 9 o'clock position for all multi-position meter packs / vertical stacks
for service amperes / voltage listed above.
2. 5th jaw will be found 9 o'clock position for stand-alone, single meter sockets and
single-position meter / main combos for service voltage listed above.
NEUTRAL
208 V
208 V 208 V
240 V
240 V 240 V
120 V
120 V
208 V
120 V
120 V
208 V
1. High Leg (Wild Leg) must terminate at the right-hand jaw of the meter socket and be either
orange in color or marked with orange tape. The high leg (wild leg) will then terminate on the
center lug position of the main service disconnect.
2. Refer to ASM Section 400 for availability.
NOTE 1
NEUTRAL
480 V
480 V 480 V
277 V
277 V
277 V
1. Knife blade switch without overcurrent protection fulfilling cold sequence meter disconnect
requirement on source side of meter socket.
2. Limit to 200 Amperes - for exception see ASM Section 200.
240 V
240 V 240 V
NOTE 2
NOTE 1
CONSTRUCTION NOTE(s): (FIGURE 1000-8)
1. Grounded phase in the center position of meter socket.
2. If 5th jaw is found at 9 o'clock position, it must be relocated in the field to 6 o'clock
position for this service voltage listed above.
3. Refer to ASM Section 400 for availability.
480 V
480 V 480 V
NOTE 2
NOTE 3
CONSTRUCTION NOTE(s): (FIGURE 1000-9)
1. Knife blade switch without overcurrent protection fulfilling cold sequence meter disconnect
requirement on source side of meter socket.
2. If 5th jaw is found at 9 o'clock position, it must be relocated in the field to 6 o'clock position
for this service voltage listed above.
3. Grounded phase in the center position of meter socket.
4. Refer to ASM Section 400 for availability.
5. Limit to 200 Amperes - for exception see ASM Section 200.
1. Customer shall label meter socket: 3PH - 3W UN-Grounded Supply. Label shall be an
engraved permanent placard and securely adhered to the meter socket.
2. Bonding strap between the center conductor and meter socket enclosure must be removed.
3. If 5th jaw is found at 9 o'clock position, it must be relocated in the field to 6 o'clock position
for this service voltage listed above.
4. Refer to ASM Section 400 for availability.
1. Customer shall label meter socket: 3PH - 3W UN-Grounded Supply. Label shall be an engraved
permanent placard and securely adhered to the meter socket.
2. Knife blade switch without over current protection fulfilling cold sequence meter disconnect
requirement on source side of meter socket, list of approved devices provide in ASM Section
1100.
3. If 5th jaw is found at 9 o'clock position, and it must be relocated in the field to 6 o'clock position for
this service voltage listed above.
4. Bonding strap between the center conductor and meter socket enclosure must be removed.
5. Refer to ASM Section 400 for availability.
6. Limit to 200 Amperes - for exception see ASM Section 200.
VOLTAGE
120/208V 120/240V 208Y/120V 240V 240/480V 480V 480Y/277V
1PH 3W 1PH 3W 3PH 4W 3PH 3W & 1PH 3W 3PH 3W 3PH 4W
(NETWORK) 240V
3PH 4W
200 AMPS PERMANENT: SELF-CONTAINED SELF-CONTAINED
OR LESS CLAMP-JAW LEVER BYPASS METER SOCKET CLAMP-JAW LEVER BYPASS
TEMPORARY: HORN / CLAMP-JAW LEVER BYPASS NOT METER SOCKET & LINE SIDE SAFETY
REQUIRED IN METER SOCKET SWITCH (KNIFE-BLADE SWITCH W/O
OVERCURRENT PROTECTION)
SERVICE
INSTALLATION 201-320 SELF-CONTAINED
AMPACITY /400 AMPS CLAMP-JAW LEVER BYPASS
N/A SEE ASM SECTION 1001
METER SOCKET
(PERMANENT &TEMPORARY)
401-3000
SEE ASM SECTION 1001
AMPS
1001.01 SERVICES
A) All service equipment must be installed and bonded / grounded per the latest edition
of the NEC or local inspection authority. Refer to ASM Section 500.
B) Metering instrument transformers will not be allowed inside Ameren padmount
transformers on any new service, upgraded service, or service modifications meeting
Rewire Work Policy found in ASM Section 200.
C) Single phase 120/240 volts, three phase 208Y/120 volts, and three phase 240/120 volts
Delta installations requiring 400 amperes continuous and greater will require metering
current transformers (CT).
D) For 240/480 volts, 480Y/277 volts, and 480 volts services greater than 200 amp, metering
current transformers (CT) and potential transformers (PT) will be required.
For exception, see ASM Section 200.
E) For 3 phase 3-wire 240 & 480 volts floating (ungrounded) delta, the unmetered phase will
be a solid link and in the center position with CT enclosures.
F) For Corner Grounded Delta 3 phase 3-wire 240 & 480 volts installations, the unmetered,
grounded phase will be in the center position, commonly called “B Phase”, within the CT
enclosure.
G) Customer shall provide the proper CT / PT enclosure as specified below.
H) Ameren Missouri will provide the wire harnesses, meter socket, CTs and PTs.
I) Ameren Illinois will provide the wire harnesses, CTs and PTs.
J) Specific Ameren Illinois downtown areas of Bloomington, Champaign, Danville, Decatur,
Galesburg, Normal, Ottawa, Peoria, and Urbana are designated as heavy underground,
grid networks, and / or spot networks. Service restrictions are specific to their
corresponding area and Customer should consult Company to determine the voltage and
method of supply that will be available prior to beginning customer engineering or
purchasing of equipment. Refer to ASM Section 1350 for more details.
K) For Ameren Missouri, the Downtown St. Louis Underground District is the area bounded by
Twenty-Second Street, Cole Street, Spruce Street, and the Mississippi River, and is
designated as heavy underground, grid networks, and / or spot networks.
Service restrictions are specific to their corresponding area and Customer should consult
Company to determine the voltage and method of supply that will be available prior to
beginning customer engineering or purchasing of equipment, refer to ASM Section 1300.
E) The customer is responsible for installing Ameren provided CTs and PTs.
F) Meter sockets shall normally be installed along the side of the CT / PT enclosures.
S Enclosures shall be installed so that any work to be performed by Ameren personnel
can be done from final grade level without the aid of a ladder.
S Where this is impractical, contact the Field Metering Supervisor and Field Supervisor
Engineer for direction.
G) CTs and PTs are required on all 480Y/277 volts and 480 volts services greater than 200
amperes. For exception, see ASM Section 200.
H) CTs are required on all 120/240, 208Y/120, 240/120, and 240 volts services 400 amperes
continuous and larger.
I) Bar type CTs are used for the following installations:
S 480Y/277 volts and 480 volts services from 201 to 1200 amperes and
S 120/240 volts, 208Y/120 volts and 240/120 & 240 volts from 401 to 1200 amperes.
J) Large window CT is used for standard service voltage from 1201 to 3000 amperes.
K) For non-standard service voltages such as 240 and 480 volts 3-phase, 3-wire services.
Refer to ASM Section 400.03 for maximum service size.
L) 480 volts installations shall contain an Ameren approved side mounted
potential transformer enclosure with 1 in. closed nipple. If longer than 6 in., make
1-1/2 in. continuous galvanized steel RMC with bonding bushing or schedule 40 or
greater PVC conduit.
M) Potential transformer enclosure must be metal with a removable mounting bracket for
installing PTs and must have the minimum dimension of 12 in. W x 36 in. H x 8 in. D.
N) Potential tap holes (#10 - 32 or ¼ in. - 20) shall be located on the bus closest to the front
on the line side of the CT for each phase. Each hole shall be drilled and tapped through
the entire bus, with lugs sized to accommodate a #10 wire, for each phase and neutral
bus. Potential tap holes are not required for the individual phase for services from 201
through 1200 amperes; Potential tap holes and lugs are required for the neutral in all
cases.
O) Conduit between the CT enclosure and meter socket shall be 1-1/2 in. galvanized steel
RMC with bonding bushing, or schedule 40 (or greater) electric grade PVC. For Illinois, if
using schedule 40 or greater electric grade PVC conduit, an equipment grounding
conductor no smaller than #10 copper should be provided between the meter socket and
CT enclosure. For Missouri installations, the equipment grounding conductor is provided in
the 11 - conductor meter bundle (harness).
P) Meter bundle (harness) CT wire must not route through PT compartment to gain access
to the meter enclosure.
Q) All service equipment, including CT enclosure must be grounded and bonded per the latest
edition of the NEC or local inspection authority. Refer to ASM Section 500 for Ameren
grounding requirement.
R) CT enclosure must be mounted from 36 in. minimum to 66 in. maximum above finished
grade to the center of the CT enclosure.
S) CT enclosure must be mounted on a flat, even surface such that the enclosure door should
open and close properly. When mounted on an uneven surface, such as brick or
architectural stone, uni-strut mounting of the enclosure is required. In any case, if CT
enclosure doors do not open or close properly, Ameren may require installation of uni-strut
or some other equivalent mounting structure to correct the problem.
T) Dimension requirements for Ameren approved CT / PT enclosures:
Ampacity Rating Minimum Dimensions for Min Dimensions for Minimum Dimensions
1PH & 3PH Bottom Entry / Bottom Exit Bottom Entry / Bottom for Top Entry /
Exit or Top Entry / Top Bottom Exit or
Applications or Top Entry / Top Exit Exit with designated Bottom Entry / Top
(W” x D” x H”) wire way inside Exit
(Note A1) enclosure (W” x D” x H”)
(W” x D” x H”) (Note B1 & B2)
(Note A2)
400A 36” x 15” x 60” 24” x 11” x 48” 24” x 10” x 48”
600A - 800A 36” x 15” x 60” 36” x 11” x 48” 24” x 10” x 48”
1200A 36” x 14” x 64” 46” x 14” x 54” 36” x 14” x 54”
(Must add side gutter:
24” W x 15” D x 64” H)
1600A 40” x 14” x 64” 50” x 14” x 64” 36” x 14” x 60”
(Must add side gutter:
24” W x 15” D x 64” H)
2000A 40” x 14” x 64” 50” x 14” x 64” 40” x 14” x 64”
(Must add side gutter:
30” W x 15” D x 64” H)
2500A - 3000A 44” x 20” x 78” 50” x 20” x 72” 42” x 20” x 72”
(Must add side gutter:
44” W x 21” D x 78” H)
2. Line side conductors entering top section of CT enclosure. CT dots pointed up.
Load side conductors leaving bottom portion of CT enclosure. This would include
exiting through the lower back.
A) Customer owned switchboards utilized for Service Equipment must contain a Main Service
Disconnecting Mean and associated overcurrent protection. This may consist of a group
operated knife blade switch(s) and fuse(s), or in lieu of the aforementioned, a circuit
breaker(s). Customer may elect to incorporate a utility metering section within the
switchboard lineup but MUST be approved by Field Metering Supervisor and Field
Supervising Engineer early in design stage for availability of indoor application(s).
B) When incorporating utility metering within a switchboard lineup, it must contain dedicated
compartment(s) for the purpose of housing Ameren provided current and voltage
transformers. PT compartments are only required for 480Y/277 volts and 480 volts
services. Refer to ASM Section 200 for location requirements and ASM Section
1001.03(T) for minimum dimension requirements for the CT / PT compartments.
C) These compartments must be dedicated to Ameren equipment. Front hinged doors shall
be provided with padlocking and sealing provisions for securing by Ameren.
D) CTs and PTs must be readily accessible from the front of switchboards for ease of
installation and removal.
E) Busbar for all phases and a neutral reference lugging system shall be included in this
section. Some manufacturers may choose to run the neutral busbar through this section as
an alternative to the neutral lugging system.
F) CT and PT compartments must be hinged and pad lockable. Separate doors must be
provided for the CT and PT compartment(s).
G) No obstructions or busbar that might restrict free and easy access to the CTs and PTs are
allowed in front (hinged door side) of the CT or PT.
H) Customer equipment shall not be located within or accessible through this dedicated
compartment(s).
I) CT and PT compartments must be separated and have barriers from other customer
compartments to prevent access.
J) Metered and un-metered conductors shall be separated by insulated barriers.
K) Ameren meter / main switch shall be arranged in hot sequence configuration, allowing
the meter to remain hot when main service disconnect is in the off position.
L) Potential tap holes (#10 - 32 or ¼ in. - 20) shall be located on the line side of the bus
closest to the front, drilled and tapped through the entire bus, with lugs sized to
accommodate a #10 gauge conductor, for each phase and neutral bus.
M) Outdoor located CT / PT switchboard sections shall be weather and rain resistant
(NEMA Type 3R).
N) All switchboards must be UL / ETL listed and meet minimum UL / ETL requirements
for steel and aluminum structures.
O) Bottom of CT / PT section shall be no lower than 24 in. for both underground and
overhead fed switchboards.
P) Top of CT / PT section shall be no higher than 78 in.
Q) All service equipment must be grounded and bonded per latest edition of the NEC or local
inspection authority. Refer to ASM Section 500 for Ameren grounding requirements.
R) Refer to ASM Section 1001 for Ameren approved switchboard manufacturer drawings
for CT and PT sections for 600 volts and below switchboards. Switchboards built per one
of these approved drawings do not require Ameren approval prior to manufacture or
installation. Switchboards not meeting one of these drawings must be approved by the
Ameren Metering Department prior to manufacture.
S) Refer to ASM Section 400 for non-standard service voltages such as 240 and 480 volts
3-phase 3-wire maximum service sizes.
T) Dimension requirements for CT and PT compartments in switchboards
1) CT compartment dimensions and requirements
S 401-4000 amperes: 120/240 volts, 240 volts, 240/120 volts, 208Y/120 volts
S 201-4000 amperes: 240/480 volts, 480Y/277 volts, 480 volts
Where this is impractical, contact the Field Metering Supervisor and Field Supervising
Engineer for direction.
4. Conduit between the CT / PT enclosure and meter socket shall be 1-1/2 in. galvanized steel
RMC, aluminum RMC, or galvanized EMT with bonding bushing, or schedule 40 (or greater)
electric grade PVC. If schedule 40 (or greater) electric grade PVC conduit is used,
an equipment grounding conductor no smaller than #10 copper should be provided between
the meter socket and enclosure. For Missouri installations this bonding jumper is provided in
the 11/C meter bundle (harness).
5. Ameren will terminate the metering conductor on each end.
VOLTAGE
120/208V 120/240V 208Y/120V 240V 240/480V 480V 480Y/277V
1PH 3W 1PH 3W 3PH 4W 3PH 3W & 1PH 3W 3PH 3W 3PH 4W
(NETWORK) 240V
3PH 4W
200 AMPS
SEE ASM SECTION 1000
OR LESS SEE ASM SECTION 1000
CT / PT
401-600 N/A CT METERING (BAR TYPE CTS) N/A METERING
AMPS (BAR TYPE
SERVICE CTS)
INSTALLATION CT / PT
AMPACITY 601-800 N/A CT METERING N/A N/A N/A
METERING
AMPS (BAR TYPE CTS)
(BAR TYPE
801-1200 N/A N/A CT N/A N/A N/A CTS)
AMPS METERING
(BAR TYPE
CTS)
1201-3000 N/A N/A CT N/A N/A N/A CT / PT
AMPS METERING METERING
(LARGE (LARGE
WINDOW WINDOW
TYPE CTS) TYPE CTS)
Customer / contractor must provide a job number provided by Ameren Missouri to pick up
the equipment. Material will not be issued without a valid job number.
12” Min
WARNING
Removing Meter does not
De-Energize Service
4” Min
36” Min
54” Min
66” Max
66” Max
Ground Level
SEE SECTION 500
GROUNDING
ELECTRODE
12” Min
WARNING
Removing Meter does not
De-Energize Service
XH
XH 4” Min
Ground Level
ELECTRODE
WARNING
Removing Meter does not
De-Energize Service
4” Min
Ground Level
WARNING
Removing Meter does not
De-Energize Service
4” Min
Ground Level
SEE SECTION 500
GROUNDING
ELECTRODE
WARNING
Removing Meter does not
De-Energize Service
4” Min
Ground Level
SEE SECTION 500
GROUNDING
ELECTRODE
WARNING
Removing Meter does not
De-Energize Service
XH
XH
XH 4” Min
54” Min
66” Max
Ground Level
SEE SECTION 500
GROUNDING
ELECTRODE
Ameren to install a
480 volt sticker on
the lid (door) of CT
enclosure
XH WARNING
Removing Meter does not
De-Energize Service
XH
XH
4” Min
Ground Level
SEE SECTION 500
GROUNDING
ELECTRODE
240 VOLTS, 3-PHASE, 3-WIRE 401 - 600 AMPERES CORNER GROUNDED DELTA
(NON-STANDARD, SEE NOTE 6)
Figure 1001-8
12” Min
WARNING
Removing Meter does not
De-Energize Service
4” Min
36” Min
54” Min
66” Max
66” Max
Ground Level
SEE SECTION 500
GROUNDING
ELECTRODE
12” Min
WARNING
Removing Meter does not
De-Energize Service
4” Min
Ground Level
SEE SECTION 500
GROUNDING
ELECTRODE
12” Min
WARNING
XH Removing Meter does not
De-Energize Service
XH
4” Min
54” Min
36” Min 66” Max
66” Max
1-1/2” Galv. Steel RMC,
Alum. RMC. EMT or Sch 40
(or greater) electric grade
PVC
Ground Level
SEE SECTION 500
GROUNDING
ELECTRODE
480 VOLTS, 3-PHASE, 3-WIRE FLOATING (UNGROUNDED) DELTA 401 - 600 AMPERES
(NON-STANDARD, SEE NOTE 6)
Figure 1001-11
12” Min
WARNING
XH Removing Meter does not
De-Energize Service
XH
4” Min
36” Min
66” Max 54” Min
66” Max
Ground Level
ELECTRODE
Lugs
Ameren
Side
provided
Gutter
CTs
4" MIN.
Lugs
54” Min
66” Max
Ground Level
A list of approved customer provided manufacturer's meter sockets (or enclosures) catalog
number in ASM Section 1100 has been removed and posted separately from the Manual due to
constant changes. To get the latest catalog number information for the meter sockets (or
enclosures), please use the website as indicated below.
BuildWithAmeren.com
Ameren is no longer sending any hard copies of Ameren Electric Service Manual and of the
Ameren Approved Metering Equipment List. If you would like to receive updates regarding the
Electric Service Manual and Ameren Approved Metering Equipment List by email, please use the
link above and complete the form. By completing this form, you are giving us permission to notify
you of important manual updates. Ameren will not share your information or use it for any other
purpose. If you were previously receiving electronic update notices and have stopped receiving
these, please submit the electronic application again as our systems are being updated.
3. Single “visible open” disconnect device per generating unit if the Ameren service being backed
up is greater than 600 volts - refer to Ameren's full requirements for details on satisfying this
requirement.
4. Transfer equipment (manual or automatic) to prevent inadvertent continuous interconnection
of sources.
5. Signage permanently installed at the revenue meter indicating:
A. the presence of generation and
B. location of the padlockable main service disconnect or a padlockable generator
disconnect for isolation. The generator disconnect must be:
• Located outside where readily accessible
• Plainly indicate whether in the open (OFF) or close (ON) position
• Can be either a knife blade switch, a load-break rated pull out switch, or
circuit breaker
6. Signage permanently installed at the padlockable main service disconnect or generators
disconnect for identifying its purpose.
1200.05 REQUIREMENTS FOR OPEN TRANSITION
1. Any of the following methods can be used:
a) Integral transfer switch with mechanical interlocking provisions
b) Kirk key interlocked solid blade switches or circuit breakers
c) Electrically interlocked circuit breakers with backup protection via hard-wired
breaker auxiliary contacts
2. Automatic transfer schemes shall include the following:
a) Voltage-sensing capability to detect the loss and recovery of the Ameren source.
b) Open transition manual “bypass” (i.e., auto disable) is highly recommended, though
not required.
1200.06 REQUIREMENTS FOR CLOSED (PARALLEL) TRANSITION
1. Any of the following methods can be used:
a) Integral automatic transfer switch set
b) Two or more solid blade disconnects or circuit breakers
2. Transfer times of less than 100 milliseconds in duration.
3. Synchronizing capability to safely tie the sources together.
4. Transfer failure scheme for opening one of the sources when closed transition exceeds a
maximum two (2.0) second time delay.
5. Undervoltage protection to prevent a closed transition transfer when the Ameren source is
not present.
6. Open transition manual “bypass” (i.e., auto disable) is highly recommended, though not required.
7. For additional requirements, refer to the Foreword of this manual for contact information
to schedule an appointment with an Ameren engineering representative.
1200.07 ADDITIONAL REQUIREMENTS FOR PROGRAMMABLE LOGIC CONTROLLERS
(PLC)
1. Independent hard-wired backup control scheme to prevent extended paralleling.
2. Enabled when transfer scheme is in “automatic” and disabled when transfer scheme is in
“manual”.
3. Automatic transfer disabled if any of the switches or circuit breakers being controlled is tripped
manually.
4. Shall not lose power as a direct result of automatic transfer switching operations.
5. For additional requirements, refer to the Foreword of this manual for contact information to
schedule an appointment with an Ameren Engineering Representative.
Voltage offered:
The St. Louis Downtown Underground secondary network distribution voltage is 216Y/125 volts,
three-phase, and four-wire (See ASM section 1300.03 for boundaries of the St. Louis
Downtown Underground District). For engineering reasons, the Company may offer 480Y/277
volts, three−phase, four−wire service where the loads warrant this voltage; however, 480Y/277
volts secondary metered service can only be provided by padmount transformation or customer
indoor substation transformers, both located on customer property. Easements will be required
as a condition of service.
Large loads, at the Company’s discretion, may be supplied and metered directly at the primary
rate from either the St. Louis Downtown 13.8 kV or all underground 12.47 kV radial distribution
system in other locations.
Choice of voltage and type of system offered depends on location and size of load. The service
point of delivery (not metering point) is at the Company’s discretion. The Customer shall consult
Company to determine the point of delivery, service voltage, and method of supply that will be
available, prior to beginning customer engineering or purchasing equipment.
Drawing submittals:
All proposed customer equipment locations, electrical configuration and ratings, and equipment
manufacturer data sheets shall be submitted to the Company for review and approval (in terms
of compliance with the Ameren Electric Service Manual or ASM rules and requirements) prior to
purchasing or installing said equipment. The customer shall provide site plan drawings and a
riser diagram (or one- line) for Company review and approval. The Company recommends
equipment and design drawing review documents to be submitted at the early stages of the
project (e.g., prior to the start of customer construction) to avoid in-service date delays and
additional customer incurred costs. Not all requirements for underground service are provided
within this document; the Company will provide any additional requirements and documents
once a Company engineer has been assigned to the project.
Conduit installation:
In accordance with the Company's tariffs filed with the MOPCS, the customer shall provide and
install all underground conduit systems within the bounds of the development
– typically, the property line – in accordance with the Company's specifications and
requirements. The customer shall provide all labor and materials to install conduit systems – to
include, but not be limited to conduit, spacers, pull ropes, manholes (from Ameren's supplier),
expendables, bollards, and other materials. Ameren will provide equipment pads, design
drawings, and standards to aid in the construction of customer provided conduit systems.
Customer requested variances to any requirements within ASM Section 1300, the
customer shall secure written approval for the variance from the Ameren Supervising
Engineer of the appropriate operating center, irrespective of any verbal approvals. The
variance shall not be considered valid or approved unless the variance is specific
and provided in writing to the customer by Ameren.
Secondary metered service shall be provided from a customer indoor substation, or indoor sub
where outdoor space is not available. When required by municipal ordinance or required by
other ASM Section 1300 subsections, the Company will provide customer requirements and
specifications for the indoor sub and will install, own, and maintain primary switches, primary
fuses, primary equipment enclosures and cables, and transformers.
The customer shall provide the indoor sub space and building elements in accordance with
Company specifications and requirements. Customer responsible building elements include but
are not limited to; the physical two room space with access well, all doors, oil retention
system, grounding system, lighting and receptacles, equipment stands, access pits, conduit or
cable tray systems, grates, and ladders. An easement for the indoor substation space shall be
required as a condition of service.
The customer shall contact the appropriate Company Division operating center prior the desired
in−service date. 9 to 12 months is required to allow for Company/Customer engineering,
equipment purchase, and construction.
Although predominantly in downtown St. Louis, indoor subs can be built within any building that
is within the Company’s service territory, if approved by the Company. Where space is
available and meets Company requirements, padmount equipment (switchgear and
transformer) is the preferred delivery method.
Consideration for network distribution system (point of service) qualification shall include new
services (where none exists), existing service upgrades, and building renovation related service
requests. At the Company’s discretion − Customers requesting new or continued network service
may qualify to be connected to or continue to be served from an existing downtown St. Louis
216Y/125 volt network distribution system if the proposed, upgraded, or continued service
connection meets the following and other applicable requirements within this service manual:
The network service connection is within the Underground District network service area,
as defined in the Ameren Missouri’s Rules and Regulations − bounded by 22nd Street,
Cole Street, Spruce Street, and the Mississippi River
The proposed network entrance points for the building (or combination of buildings) or
structure shall be at only one location, with the Company provided network service
cables terminated as noted in the following tap box ASM section 1300.
Service or services distribution panel(s) aggregate size at 216Y/125 volts equals 1,200
amperes or less (this means that if not upgraded to the radial distribution system,
the customer’s network service will be restricted to 1200 amperes at 216Y/125
volts, in perpetuity); if a customer appears to qualify for network service based on the
aggregate panel size, but also appears to have building capacity for load growth
beyond 1200A, said new service may still not qualify for network service, at the
Company’s discretion.
Services greater than 1200 amperes (aggregate) shall be supplied from the 13.8 kV
radial distribution system (point of service) by means of a padmount transformer or
customer indoor substation (see ASM section 1300.02).
For new 480Y/277 volts customer requested services, Ameren will not construct any new spot
networks (480Y/277 or 216Y/125 volt services by network transformers within sidewalk vaults).
Customers seeking 480Y/277 volts secondary metered service within the network service area,
secondary service shall be supplied from the 13.8 kV radial system by means of a padmount
transformer or customer indoor substation.
Once a Customer qualifies for 216Y/125 volt network distribution service, service connection
at the service entrance point shall be by one of three service connection means:
1) Company network cables terminated at a customer provided network tap box (see tap box
spec ASM Figure 1300−1A and 1300-1B).
2) Company network cables terminated at a customer owned commercial grade 600 volts (or
less) switchboard (see ASM Figure 1300−2A); or
Drawings:
Due to the possibility of customer 216Y/125 volts distribution being exposed to available high
fault currents when connected to the Company’s downtown St. Louis 216Y/125 volts network
distribution system, the Company and the City of St. Louis Authority Having Jurisdiction require a
main switch and current limiting over−current protective device (OCPD) to be installed for all
customer service entrance equipment, immediately downstream of the supply side termination lugs.
The City of St. Louis is enforcing NEC Article 110.10 in requiring an appropriate OCPD for customer
equipment, for all customer service connections to the downtown network distribution system.
Service connections to the downtown network distribution system, under NEC Article 230.71,
Maximum Number of Disconnects, or the “6 Switch Rule,” shall NOT be allowed.
Customers requesting to connect Distributed Resources (DR) – i.e. solar voltaic, batteries, or motor
generators – for the purposes of net−metering (not emergency or standby generation), to either the
low voltage network distribution system (216Y/125 volt grid or a 480Y/277 volt spot network), shall
comply with the Company’s net metering network requirements as a condition of service, in addition
to the standard requirements for service, as stated in the Company tariffs filed with the MOPSC.
Underground Engineering will provide network service net-metering requirements (Network
Distribution Resources (DR) Connection Engineering Guideline) upon request.
For multi−story high rise residential projects and customer provided distribution equipment for
metering on multiple floors – up to and including every floor – Ameren will approve such a customer
distribution equipment configuration if the following numbered requirements are met:
1. The customer provided distribution system configuration meets ASM Figure 1300−2A/2B.
2. Bus duct riser distribution voltage can be either 480Y/277 volts 3−phase 4−wire or
208Y/120 volts 3−phase 4−wire (a combination of the two voltage configurations for the
residential services shall not be allowed).
3. Secondary metering voltages shall be 480 volts − 120/240 volts 1−phase 3−wire or 480 volts −
120/208 volts 2−phase 3−wire, at the point of metering.
5. Secondary metering voltages shall be balanced so that the 3−phase loads are balanced
(e.g., for either 120/240 volts 1−phase 3−wire or 120/208V 2−phase 3−wire, rotate AØ−BØ,
BØ−CØ, CØ−AØ, and soon).
6. All customer provided distribution equipment shall be new, meet local electrical
codes, and UL Listed for their intended use.
7. The bus duct riser system shall include a main disconnect located at the service entrance
point; the unmetered panel shall include only the secondary cable termination compartment
(front access), the main disconnect and OCPD, and the bus duct connection point; all side
and back compartments shall include factory installed tamper proof screws.
8. All distribution equipment on the metering floors shall be modular bus plug−in design, except
only for the cable connections between the high and low side transformer connections.
9. Transformers on the metering floors shall be dry type transformers and shall meet the
energy efficiency requirements of the DOE Energy Policy Act of 2005; refer to Federal
Register 10CFR Part 431, date 4−18−13.
10. Transformers on the metering floors shall be sized in accordance with the local codes and
shall have a minimum reserve capacity of 25%, over and above any code required excess
capacity.
11. The metering spaces shall be sized to allow for future removal and replacement of the
floor dry type transformer, and the metering space doorway shall be large enough to allow
the transformer to be removed from the meter space, without removing the door from its
hinges.
12. Floor metering space dry type transformers’ size and weight shall be such that they can be
moved up and down the building using a standard passenger elevator system.
13. The customer shall provide one spare dry type of transformer for each size that will be
connected to the distribution equipment; the spare transformers shall be stored within the
first meter room space and include labels to identify the transformer(s) as spare units.
14. The building distribution riser shall be a secondary bus duct riser – cable secondary risers
shall not be allowed – and of sufficient ampacity (copper or AL conductors) to meet the
local code requirements and the requirements of this ASM section 1300; the bus duct
requirement includes any horizontal bus duct between the service entrance main
disconnect switch and the transition to the vertical bus duct riser; relative to any existing
bus duct that must be replaced (due to age or equipment failures), the replacement bus duct
shall be bus duct with equivalent ratings and specifications.
15. The bus duct riser shall be designed such that the connection points for the bus duct are
accessible only at the metering floors and shall accept bus plug−in devices to tap power to
the metering floor.
16. The bus duct tap point on the metering floor shall include a disconnect so that the metering
equipment on that floor can be de−energized and locked out, without having to de−energize
the entire bus duct riser (and all other upstream and downstream customers).
17. The bus duct shall be sized to meet all local code requirements and ANSI / IEEE
C84.1, Voltage Range A, at the point of utilization.
18. The customer shall be responsible to mitigate voltage flicker due to motor starting and / or
other intermittent loads on the secondary side of the step−down dry−type transformer. The
voltage flicker shall be less than the noticeable curve defined in ANSI / IEEE 141. The
customer may be required to provide documentation indicating how this requirement is m et.
19. Ameren shall reserve the right to review all proposed customer distribution equipment, to
include, but not be limited to equipment sizes, configuration, disconnects, transformers, and
metering equipment, prior to the customer releasing the equipment for fabrication, relative
to compliance with Company service rules.
20. All proposed metering equipment shall comply will all Company metering requirements, as
given in the current edition of the Ameren Electric Service Manual, and the requirements of
this ASM section 1300 for the purpose of metering multi−residential high-rise structures.
21. The customer shall provide a 120V 1P-20A receptacle within each meter center room for
powering metering radial repeater equipment, as required. The 120V receptacle shall be
located as directed by Ameren within the meter rooms. The customer shall also provide a
conduit to the exterior of the building for pulling in an antenna cable between the meter
center room repeater and an exterior antenna (final locations to be coordinated between
Ameren and the customer).
23. The customer shall provide a detailed one-line diagram showing all proposed meter room
equipment and their connection configuration and equipment ampacity sizes; this can be
shown on the building one line or riser diagram.
24. All equipment within the metering room shall include provision for metering seals or locks
and side panels shall include tamper proof screws to prevent access.
25. The dry−type transformer / metering room shall not be used as a janitorial or storage closet
and shall not include customer equipment such as, but not limited to plumbing piping and
controls and water heaters.
26. All customer metering equipment (bus duct riser, modular meter center equipment, and mains)
and the customer metering equipment configuration shall be reviewed by the Company prior to
the customer purchasing and installing such equipment.
This ASM section 1300 also applies to high rise developments outside the downtown St. Louis
service area, where secondary service is provided by means of a padmount transformer or
customer indoor substation. In these cases, ASM Figure 1300−2B would apply for either a
padmount or customer indoor sub installation transformer (the shown padmount in ASM Figure
1300−2B would be substituted with an indoor substation transformer−all other requirements
remain the same).
Drawings:
It is the responsibility of the property owner or customer requesting service to provide all
conduit and connectors on their property. Depending on location, Customer may be required
to install conduit from Company service vault or manhole to customer's property, including
work in public right of way. The Customer is required to contact the Company when working in
Heavy Underground areas to determine who will be responsible for conduit installation in
public right of way. If Company installs the conduit up to the property line, the Customer shall
coordinate the location of where the Company's conduit and Customer's conduit will meet.
Customer will be responsible to make sure conduit from both parties match the required
number, size and type. Depending on potential growth or expansion, the Company may
require spare or additional conduits.
Company will install and maintain cable up to the point of delivery.
Customer shall provide the indoor substation space, building elements, and any required
easements in accordance with Company specifications and requirements. Customer is responsible
for building elements that include, but are not limited to, the physical space with proper access for
Company equipment to be installed/removed, all doors, oil retention system, grounding system,
lighting and receptacles, equipment stands, access pits, grates, ladders, etc.
Customer shall contact the appropriate Company Region operating center a minimum of twelve
months prior to the desired in−service date. This lead time is required to allow for
Company/Customer engineering, equipment purchase, and construction.
Although the heavy underground and network areas are identified below in Ameren Illinois, indoor
metering and any requirements as set forth in this section and ASM Section 200 may be built
within any building that is within the Company service territory, if approved by the
Ameren Field Supervising Engineer and Field Metering Supervisor. Where space is
available and meets Company requirements, outdoor padmount equipment (switchgear
and transformer) is the preferred delivery method in these commercial and heavy
underground areas.
C. Peoria: Peoria grid network voltage is 480Y/277V. Grid network services provided at
480Y/277 require cold sequence metering (meter disconnect) for all instrument rated
and self-contained metered services. Buildings with residential services will be required
to use a step-down transformer to serve 120/208 volts 3-wire, grounded neutral
"referred to as network metering" from the grid network 480Y/277V system and will be
the responsibility of the property owner to install and maintain. See ASM Figure
1350-3 for approximate grid network area.
Customers planning to take a network service from the downtown grid can take service by one of
two service connection means:
1. Company network cables terminated at a Customer provided network tap box (see tap
box spec drawings ASM Figures 1350-4A &1350-4B);
2. Company network cables terminated at a self−contained meter socket (exception for
Peoria 480Y/277V network, cables would be terminated at the Customer's meter
disconnect). See ASM Section 200 for self-contained metering requirements.
If the network service connection involves multiple metered services at the same premise or
requires parallel runs of service conductors, the Customer shall provide a network tap box, as
specified in this section. New customer connections to the network distribution system, whether
a completely new service or an additional service(s) to an existing network tap box, shall be
reviewed and approved by the local Ameren Field Supervising Engineer prior to the start of
any construction. For typical network service layout connections see ASM Figures 1350-5 and
1350-6.
Network tap boxes allow for multiple service connections from a single service point within a
building and allows Ameren to install equipment on the service cables. Buildings that
have multiple, or potential to have multiple, service connections will be required to be
provide an approved Ameren network tap box, see A S M Figure1350-4A and
1350-4B for dimensions and specifications. The network tap box will be
purchased and installed by the Customer. All connections made within the tap box will
be made by the Company. Network tap boxes will be pad locked by Company and will have
exclusive rights to enter the tap box, no Customer access within the box once installed.
Network tap boxes location must be approve by Company before installing. All Conduit
and building modifications (core drills or wall penetrations) will be the responsibility of
the customer. New services requested from the network tap boxes will be the
responsibility of the building owner or customer requesting the service to install all
required conduit, cables, connectors between the network tap box and the new meter
location. Company will make final connection within the network tap box. Network tap boxes
can be located outside but will be the responsibility of the Customer to provide suitable
location that meet all Company clearances and all local codes/ordinances.
Due to the possibility of networked distribution being exposed to high fault currents
available when connected to the Company’s downtown network distribution systems, the
Company and the Authority Having Jurisdiction (AHJ) require the main service disconnection
and current limiting overcurrent protection device (OCPD) to be adequate for the available
fault current in these installations. This main service disconnect and over current protection
will be required to meet the latest adopted NEC requirements for all customer service
connections to the downtown network distribution systems. In multiple meter locations for
residential units in these network systems, the customer will be required to balance their total
building load across all three phases.
1. Ameren is committed to both the safety of the public and its employees while maintaining
reliable operation of its distribution system. Installations involving customer-owned and
operated Distributed Energy Resources (DER) create the potential for serious personal injury
as well as damage to the Customer’s or Company’s equipment.
2. In order to minimize potential dangers to utility employees and the public, all DER installations
such as photovoltaic (PV), wind, energy storage systems (ESS), motor driven generators, or
other systems shall adhere to UL 1741, IEEE 1547, and applicable requirements of the
National Electrical Safety Code, the National Electrical Code, Institute of Electrical and
Electronics Engineers (IEEE), Underwriters Laboratories(UL), Electrical Testing Laboratories
(ETL), local electric codes, applicable NEMA codes, OSHA, AHJ, and Company’s Electric
Service Rules as set forth in published tariffs. A customer must make application to install
DER through the Ameren Missouri Renewable Energy Program website:
Link to Residential Customers
Link to Business Customers
3. Anti-islanding protection is a way for the DER system to sense when the immediate utility
supply circuit is disconnected from the remainder of the utility grid. This standard prevents the
DER from injecting real or reactive power into an islanded utility supply circuit, thereby
mitigating a potentially hazardous condition for utility workers and the public. However, this
requirement shall not be construed to prevent the DER/ESS system from continuing to feed
the customer's critical loads using automatic transfer switches, manual transfer switches, or
mechanical interlocks to prevent back feed onto the utility grid.
4. For Behind -the-Meter (BTM) interconnections ≥ 200 kW, Ameren Missouri reserves the right
to require a non-revenue production meter to monitor DER generation. For ESS systems
with export capacity greater than 25 kW, Ameren Missouri reserves the right to require a
revenue grade meter to monitor the output of the ESS to ensure that exporting ESSs are
only charged by renewables (i.e., proper mode selection).
5. Careful selection of customer owned transformer and their protective equipment located on
the load side of main disconnecting means must be made to prevent excessive overheating
and to ensure detection of abnormal conditions such as Loss of Phase events, see
ASM Section 900. The consequences of not detecting the Loss of Phase condition would
be a violation of Standard IEEE 1547. Compliance with IEEE 1547 is required by Ameren
Missouri for all customer with DER interconnections.
6. Customer's DER system must include a lockable AC generation source disconnect that is
operable and can be locked in the “OFF” position by Ameren Missouri personnel, Customer,
and emergency personnel. This disconnect switch will allow the DER system isolation from
Company's distribution facilities for maintenance, reliability, and safety concerns. Any HOLD
OFF tags or clearances given to the Customer's lockable AC generation source disconnect
must be honored by Ameren Missouri personnel, the Customer, and emergency personnel.
Refer to ASM 1400.02.7 and ASM 1400.02.8 for specific location requirements.
7. The lockable AC generation source disconnect shall be labeled by the customer with
permanent placarding stating, "LOCKABLE AC GENERATION SOURCE DISCONNECT”.
8. If the lockable AC generation source disconnect is greater than 10 ft from the revenue meter or
not within sight of the revenue meter, additional permanent placarding stating “CAUTION:
MULTIPLE SOURCES OF POWER – LOCKABLE AC GENERATION SOURCE
DISCONNECT AVAILABLE FOR ISOLATION FROM UTILITY” shall be installed. It must also
have additional verbiage to explain the exact location of the generation disconnect. Most
times, there is a site overview map showing the facilities and identifying where the main service
disconnect, and the AC generation source disconnect is located.
A) Permanent placards must be engraved on hard plastic and adhered to the meter socket lid
and lockable AC generation source disconnect with permanent adhesive or adhered to the
building exterior surface immediately adjacent.
B) Use of a label marker or glued-on strips is not acceptable.
9. For an ESS integrated with DER installations, all premises must have a lockable ESS
disconnecting means on the AC side of the DER system for an AC coupled ESS or on the DC
side of the DER system for a DC coupled ESS, or its remote control, located at
10. For an ESS serving a critical load panel, an integral or external automatic transfer switch
(preferred), manual transfer switch, or mechanical interlock that allows transferring from the
utility source to the DER/ESS system and vice versa must be installed. This transfer switch
allows Ameren to disconnect utility power to the inverter by operating the lockable AC
generation source disconnect for completion of the witness test without interrupting power to
the critical load panel. If the customer elects to install an ATS, the normal source should be
utility grid power. If a manual transfer switch or mechanical interlock kit is used, then the critical
load panel must be served by utility grid power until the witness test is completed. After the
completion of a successful witness test, the customer or installer should swap the manual
transfer switch or mechanical interlock kit over to the normal feed is from the inverter AC
output.
11. If a PV installation is served by more than one lockable AC generation source disconnect, then
each disconnect must have a permanent placard depicting an aerial view of the location
(including the boundaries of the respective PV panel systems) and the location of all lockable
AC generation source disconnects. This placarding must identify how to de-energize a
particular section of PV generation to ensure the safety of personnel working around the PV
system and emergency responders. Additionally, each PV panel system shall have uniquely
identifiable permanent placards matching the respective lockable AC generation source
disconnect.
12. Customer DER systems must include appropriate wiring and metering equipment if the
customer wants to sell or receive credit for excess electricity generated by the DER being
injected back into the Ameren Missouri electric distribution system. The customer must file an
application, including a detailed one-line diagram (when applicable), so that the process for
interconnecting a proposed DER installation can begin.
13. Sales of electricity are regulated by various state and federal agencies, and it is the customer's
responsibility to investigate all state and federal agency requirements before filing an
application.
2. Customer is responsible for protecting their generator’s equipment in such a manner that faults
or other disturbances on the Ameren Missouri electric distribution system or on Customer DER
system do not cause damage to their equipment.
3. Customer shall furnish information to Ameren Missouri regarding their proposed generation
equipment and protective devices prior to parallel operation. Company will check the
adequacy of this proposed equipment and its compatibility with protective devices on the
Company’s system and will either approve as submitted or specify additional equipment which
will be required to begin parallel operation with the Company’s system.
4. Per the Ameren Service Manual, any work or wiring changes at the service will prompt the
need to upgrade equipment to the latest service manual requirements, including but not
limited to installing a lever bypass meter socket or CT enclosure.
5. Meter sockets and metering equipment enclosures are not to be used as junction boxes or
raceways for customer owned distribution circuit wiring or alternate power source(s) circuitry
and monitoring equipment. Only service entrance conductors are permitted in those metering
enclosures. Once service entrance conductors leave the meter socket or metering equipment
enclosure(s), they cannot re-enter the enclosure for any reason. Customer owned CTs and
cabling used to monitor their loads and / or DER production output are not allowed inside the
meter socket or metering equipment enclosures. Unauthorized wiring and equipment shall be
removed by the customer at no expense to Company.
6. Customer's lockable AC generation source disconnect switch shall comply with the following:
2) Load-break-rated pull-out-switch
d) Enclosures with doors or hinged covers that are readily accessible to unqualified persons
and have exposed live parts when the enclosure is opened must be secured in a manner
that requires a tool to open the enclosure or must be lockable.
g) Have ratings sufficient for the maximum circuit current, available fault current, and voltage
that is available at the terminals.
h) Be marked with a warning when the line and load terminals are capable of being energized
in the open position.
i) The lockable AC generation source disconnect switch must be within reach, with a
maximum mounting height with the handle no higher than 6'7" above grade when in the
"UP" or ON position.
j) When the lockable AC generation source disconnect is a knife-blade safety switch (fused
or non-fused), the conductors coming from the DER system must terminate on the bottom
lugs of this disconnect. Utility supply will terminate on the top lugs of this disconnect.
k) When the lockable AC generation source disconnect is a Circuit Breaker, the utility supply
shall terminate at the ON side lugs of the breaker. The conductors coming from the DER
system shall terminate at the OFF side lugs of the breaker.
7. A LOAD SIDE TAP is when the DER connects downstream of the customer's main service
disconnect. The lockable AC generation source disconnect will be located outdoors, readily
accessible, within 10 ft of the electric revenue meter, and between the inverter and a circuit
breaker or fuse (overcurrent protection device - OCPD) located in the main distribution panel.
This disconnect switch may or may not have overcurrent protection in this device. The
maximum size of the proposed DER system is limited by the main service disconnect ampere
rating, associated bus rating, and overcurrent protection device rating. Taking these values
into account, the maximum size of the DER system can be calculated per NEC requirements.
The lockable AC generation source disconnect switch must have an equipment grounding
conductor that originates at the main service disconnect and terminates on the enclosure
The lockable AC generation source disconnect switch may have the following depending upon
system configuration:
a) System neutral
b) Overcurrent protection
8. A LINE (SUPPLY) SIDE TAP is when DER interconnections are made between the customer's
main service disconnect and Ameren's metering instruments or self-contained meter. A Line
Side Tap requires a DER Main Disconnecting Means with overcurrent protection, similar as the
Main Service Disconnecting Means. In some cases, the DER Main Disconnecting Means may
also serve as the lockable AC generation source disconnect switch. When the lockable AC
generation source disconnect is located downstream of the DER Main Disconnecting Means,
the lockable AC generation source disconnect switch may or may not have over-current
protection in this device. The lockable AC generation source disconnect must be outdoors,
readily accessible, and mounted within 10 feet and in sight of the electric revenue meter and
within 4 feet of the POI. If this distance cannot be maintained – consult with your Ameren
representative. The size of the proposed DER installation is limited by the ampere ratings of
the service entrance conductors, metering equipment, and other service equipment ratings.
9. LINE (SUPPLY) SIDE TAP POINT OF INTERCONNECTION (POI) must comply with the
following requirements:
a) Conductors running from the POI to the DER Main Disconnecting Means and overcurrent
protection device shall be no smaller than #6 AWG copper or #4 AWG aluminum.
b) The conduit running from the POI to the DER Main Disconnecting Means shall contain only
DER service entrance conductors. Monitoring cables and other customer circuitry are not
permitted.
c) If the customer chooses to install a production meter, it must be located after the DER Main
Disconnecting Means (e.g., on the generator side).
d) Where the DER circuit makes a POI outside of a building or at a meter structure (OH or UG),
it shall be protected by an overcurrent device(s) at a readily accessible location outside the
building, near a meter structure, or where the DER conductors enter the building. The
overcurrent protection device shall be located within one of the following criteria:
3) 20 ft horizontally or 30 ft of total conductor length (if bends are required) from the POI
for buildings which are not considered to be dwelling units.
*If current limiters are installed, the total conductor length can be extended by up to 41 ft
for each category above, but in no instance shall unprotected conductors extend more
than 10 ft into a building.
e) Where the DER installation makes its POI to a service inside a building, they shall be
protected by one of the following methods:
1) with an overcurrent device located within 10 ft of conductor length in dwelling units and
16.5 ft in other than dwelling units from the point of connection to the service.
2) in other than a dwelling unit, with an overcurrent device located within 71 ft of conductor
length from the point of connection to the service, if cable limiters installed in all
ungrounded conductors are located within 16.5 ft of conductor length from the point
of connection to the service.
3) The DER overcurrent protection and associated supply conductors shall be sized to
carry 125 percent of the rating of the sum of the DER sources.
f) For connections rated 1000 amperes or more to solidly grounded wye services exceeding
150 volts to ground but not exceeding 1000 volts, phase-to-phase, ground-fault protection
that meets the requirements of the NEC must be provided.
g) When interconnecting with existing 3-Ph 3-Wire ungrounded services, ground detection
sensing equipment must be installed by the customer on existing service equipment and
the new AC generation source service equipment. See ASM Section 500.
h) POI can be made in a junction box, trough, or tap box after the metering equipment but
before the main service disconnect. DER POI must be made using listed connectors and
comply with NEC enclosure fill requirements. All power distribution blocks installed on
service conductors shall be marked as "Suitable for Use On line Side of the Service
Disconnect." Effective January 1, 2023, pressure connectors and devices for splices and
taps installed on service conductors shall be marked as "Suitable for Use On line Side
of the Service Disconnect." 2020 NEC 230.46.
1) 200 amp Ameren Revenue meter socket - The POI connection can be made in some
Ameren revenue 200 amp meter sockets. The meter socket must be in good working
order and lever bypass style. Presently, Milbank is the only mfg. that has a UL rated tap
accessory kit that works only in their products. This kit allows the installer to replace the
existing slide-in nut assembly of the factory lay-in lug with a new slide-in nut assembly
that has a lug allowing for a 100 amp tap in addition to the normal lay-in lug designed
to accommodate #6-350 kcmil conductors.
2) 320 ampere/400 ampere max Ameren revenue meter socket – The POI connection
can be made in this meter socket provided there are not more than 2 barrels per lug
bolted onto the connector stud. Many of the factory lugs for this style of meter socket
have non-rotating twin barrel lugs that accommodate #6 – 350 KCM conductors.
These mfg. load side lugs must not be swapped out for different style such as stacked
or stair-stepped lugs to accommodate extra conductors.
j) CT Rated Services Installations – POI connections are not allowed inside CT enclosures.
k) POI inside Ameren Missouri meter socket or CT enclosure will not be allowed in existing
installations if this metering equipment is not deemed by Ameren Missouri to be in good
condition and an acceptable POI method for the installation.
l) Insulated connectors such as those manufactured by NSI and ILSCO (IPCS, Nimbus,
Polaris) used for making a multi-tap or insulated piercing connectors are not allowed to be
used inside meter sockets or CT enclosures for making a POI.
m) When the POI is made within a line-side junction box or on the line-side conductors within a
main service disconnect fed by multiple runs of service conductors using insulated
connectors [such as those referenced in item I.)], the POI must intercept all runs.
n) Non-insulated connectors (ex. ILSCO PTT-2L-250-Z flag connectors) are not allowed to be
used to add termination barrels inside meter sockets or CT enclosures for making a POI.
o) POI is not allowed to be made at the Ameren transformer lugs, even when customer
revenue CT instruments are presently inside the padmount transformer.
p) When making a POI, if any portion of the supply conductors/cable must be re-routed (such
as installation of a junction box/terminal box) or lengthened, then the service installation
must be upgraded to meet the current Ameren Electric Service Manual specifications,
including relocating metering instruments and meter socket from the Ameren
transformer to customer owned metering enclosures per Ameren policy found in
ASM Section 1001.
q) An alternate location to consider for making a POI if it cannot be made inside the revenue
meter socket or CT enclosure is a customer installed NEMA 3R tap box between the meter
socket and the main service disconnect.
r) POI is allowed to be made inside Customer's Main Service Disconnect where space allows.
s) CT enclosures cannot be used as a junction box or raceway to route DER conductors and
supporting DER hardware (i.e.: customer owned monitoring CTs or cabling)
t) In some cases, the existing supply conductors running from the padmount transformer/
secondary pedestal/pole to the supply side of CT rated services may have a lower
ampacity rating than the main service disconnect. Additionally, some existing customer
owned, residential, single phase service entrance conductors for 100 amperes through
400 ampere installations were sized with reduced conductor ampacity as allowed
by NEC 310.12. When making a line side tap, it should be verified that the supply
conductors / service entrance conductors are properly sized for the proposed DER
system. If the conductors are undersized, the customer must install new service
entrance conductors at their expense from customer service equipment to the utility
service delivery point.
u) When making a line side tap where the DER Main Disconnecting Means will be mounted on
a separate structure from the service installation and these structures are not mechanically
secured together to function as a single structure, then the supply conductors from the POI
at the service installation to the DER Main Disconnecting Means must be run underground
in a conduit system.
For a main service disconnect & DER Main Disconnecting Means mounted on separate
structures, the DER Main Disconnecting Means must be mounted on a building
or galvanized metal structure like as shown in ASM Section 700.
10. When making a Line (Supply) Side Tap from a service installation that is served from a
grounded secondary utility system, the DER Main Disconnecting Means must have the
grounded (neutral) conductor ran from the POI, even if Customer DER system does not require
the grounded (neutral) conductor.
1. For single-phase DER connected line to center tap neutral of a 120/240 volts
service (e.g., 120 volts line-to-neutral), its addition (or aggregate addition) may not create
an imbalance between the two sides of the 240 volts service of more than 20% of
the nameplate rating of the service transformer. This same 20% limitation would apply
to a 240/480 volt single-phase service (e.g., 240 volts line-to-neutral).
3. For DER connected line-to-line on two phases of a three-phase grounded wye system,
the maximum aggregate DER size would be 40% of the nameplate of one of the single-
phase transformers in the bank, or 40% of 1/3 of the nameplate of a unipot*
transformer.
6. For floating delta and corner grounded delta secondary systems, only balanced three-
phase connections will be allowed. This can be achieved by using a three-phase
inverter or by banking line-to-line connected inverters.
*A unipot transformer is a transformer that contains all three phases within the same tank.
This includes both overhead and padmount transformers.
**Aggregate DER refers to the sum of all such DER installations connected in the same manner
to a common transformer.
1. For three-phase BTM DER interconnections that are served by an Ameren owned
open-wye or open-delta transformer primary configurations to supply a three-phase
service voltage, the maximum nameplate capacity of three-phase DER that can be
connected is limited to 144% of the kVA rating of the smallest transformer.
2. For proposed BTM DER that exceed the limit in the paragraph above, if there are three
primary voltage phases readily available, the service transformers should be replaced
with a three-transformer bank or a single three-phase transformer to maintain phase
balancing. Charges may apply to complete this upgrade. If the upgrade requires that
the customer's total main size exceeds 600 A, the customer will be required to convert
to one of the standard three-phase service voltages shown in ASM Section 400.
Any customer requesting to connect DER – i.e., photovoltaic (PV), wind, energy storage
systems (ESS), motor driven generators, etc. – for the purposes of net-metering (not
emergency or stand-by generation) shall comply with the following requirements as a
condition of service, in additional to the standard requirements for service. All service
metering voltages will meet the standard voltages stated in ASM Section 400. Where
non-standard service voltages exist, Ameren may allow DER interconnection at Ameren
discretion.
The customer will comply with all Ameren Missouri Company general requirements for DER
interconnections that are in the applicable Missouri Administrative Code, Ameren’s Standards
and Qualifications for Electric Service, and the Ameren Electric Service Manual. A customer
must make application to install DER through the Ameren Missouri Renewable Energy
Program website:
Prior to being given Permission to Operate (PTO), all installations must pass an Ameren
Missouri administered witness test per the interconnection agreement.
On multi-phase BTM systems interconnected with service installations that are fed by dedicated
Ameren secondary facilities, Ameren may be able to complete loss of phase witness testing
using Ameren equipment.
On multi-phase BTM systems interconnected with service installations serving critical loads or
when Ameren secondary facilities serve multiple customers, the developer/installer shall provide a
means to complete loss of phase (single-phase) testing on the load side of the main service
disconnect. The developer/installer shall declare how they will facilitate the loss of phase testing
on the one-line diagram submitted with all applications. The one-line diagram must point to
permanently installed facilities to be used for loss of phase witness testing, or when temporary
equipment is to be utilized, the rating of such equipment shall be listed, and the equipment shall
be shown in an inset off to the side of the permanent one-line indicating the location where the
temporary equipment will connect. Ameren may provide feedback on the developer's/installer's
loss of phase witness testing procedure and require modifications considering customer sensitivity
and operation.
The proposed DER installation connected to Ameren Missouri shall meet the requirements
mentioned in Table 1.
References Description
IEEE SMART Inverters connected to the Utilities systems shall be rated as IEEE
1547-2018 compliant
1547-2018
UL 1741 SMART inverters connected to the Utilities systems shall be rated as UL 1741
safety compliant
Level Description
3 DER connections to the Ameren grid or spot network distribution system shall be
considered Level 3 requests. For radial distribution circuits, the aggregate export
capacity of all generation (existing and proposed) on the circuit must be no greater
than 10 MVA or less than or equal to 10 MVA if connecting to a radial primary
distribution feeder.
4 Nameplate capacity rating is less than or equal to 10 MVA and the distributed
generation facility does not qualify for a Level 1, Level 2, or Level 3 review, or the
distributed generation facility has been reviewed but not approved under a Level 1,
Level 2, or Level 3 review.
For Level 2 and Level 4 BTM DER interconnections that require Ameren Missouri planning
analysis requires system upgrades: Metering interval data, provided by Ameren Missouri, will be
required for at least one year, or if the customer is new, detailed operating load information will be
required to be provided by the customer for proper transformer and other Ameren Missouri
equipment evaluation (sizing and charges). If larger equipment is required to serve the DER than
is required to serve the load, the customer will be required to pay the difference without the
benefit of delivery service revenue credit. A functional one-line must be submitted by the
customer to enable Ameren Missouri to perform the analysis.
Due to operational complexities of network protectors found on the secondary spot and
grid network systems, Level 3 interconnections SHALL NOT export (back feed) power on
the Ameren Missouri network distribution system. It is the customer's responsibility to
install appropriate equipment to ensure the DER installation will adhere to the NO
EXPORT criteria of the Interconnection Agreement with Ameren Missouri. As part of the
Level 3 process, Ameren Missouri must conduct a thorough engineering review of the
DER interconnection application that requires interval demand information from the
customer for the previous 12 months. If Ameren Missouri does not have the interval
demand history, the customer will be responsible for all costs to install an advanced
revenue metering package to obtain this data.
Access to Premises
1. to inspect at all reasonable hours Customer’s DER and protection devices and read or test any
meter for the Facility.
2. to disconnect, at any time, without notice, the Facility if, in Ameren Missouri’s sole opinion, a
hazardous condition exists and that immediate action is necessary to protect persons, or
Ameren Missouri’s facilities, or property of others from damage or interference caused by
a) Customer’s Facility or
3. to read monthly the bidirectional digital meter for billing purposes. Self-reads and reads from
adjacent properties are not permitted.
1400.05 METERING
1. Parallel generating facilities connected to Company's system are divided into two groups:
a) No-exporting DER would apply to Customer's facilities whose load is significantly larger
than their generating capacity so that no Customer-generated power would flow into
Company's system except under fault conditions. This metering scenario also applies to
DER systems that are not allowed to export due to interconnection with Company's
secondary spot and grid networks.
For non-exporting DER, the AC generation source disconnect or associated circuit breaker will be
tripped by equipment capable of detecting the reverse power flow condition toward
Company's system. This type of installation requires a single revenue meter installation
with detent to prevent operation of the meter in the reverse direction.
b) Export capable DER would apply to Customer's facilities whose load is sufficiently
variable or smaller than its generating capacity so that excess Customer-generated
power could flow into Company's system. (Exporting Generation)
For export capable DER, the revenue metering shall include a bi-directional meter
(commonly referred to as the "net metering"). The meter will be capable of measuring
kWH in both directions; one register indicating kWH to the customer from Ameren
Missouri and a second register indicating kWH to Ameren Missouri from the customer.
2. Metering equipment shall be Ameren approved. Refer to the Ameren Approved Metering
Equipment List, which can be found at BuildWithAmeren.com.
1400.06 AMEREN WITNESS TESTING
1. The Customer understands that Ameren may conduct a witness test of the distributed
energy resource (DER) facility, from the point of interconnection to the Lockable AC
Generation Source Disconnect and from the point of interconnection to the Energy Storage
System (ESS) Disconnect, to ensure that all equipment has been appropriately installed
and that all electrical connections have been made in accordance with the applicable
codes.
2. The Customer further understands that Ameren may, but is not required to, identify wiring
and electrical equipment practices that may raise safety and/or reliability concerns for
Ameren and/or the Customer on the Customer's side of the point of interconnection.
Ameren reserves the right to identify safety and/or reliability concerns prior to or during
witness testing that could lead to the witness test being suspended or a delay in the
issuance of permission to operate (PTO) until corrections are made.
3. To the extent that Ameren does identify wiring and electrical equipment practices that may
raise safety and/or reliability concerns for Ameren and/or the Customer on the Customer's
side of the point of delivery, the Customer understands that said identifications are not
being made by certified inspection authorities and should be verified by a certified inspector
and/or local governmental authorities.
A Smart Inverter is a device that converts direct current into alternating current and can
autonomously contribute to grid support during deviations from normal operating voltage and
frequency conditions by providing each of the following: dynamic reactive and real power
support, voltage, and frequency ride-through, ramp rate controls, communication systems with
ability to accept external commands, and other functions from the electric utility.
Smart Inverters are distinguished from inverters without smart capabilities in three ways:
1. They can modify their real power (Watts) and reactive power (VARs) output to provide grid
support.
1. Parallel Generator
2. DC Disconnect
+/-
6. Ameren Bi-Directional Meter
3. SMART Inverter
7. Communication
Device/Gateway
6. Utility Bi-directional Meter. However, customer installs & owns meter socket.
7. Communication Device and/or Gateway
1. Parallel Generator
2. DC Disconnect
+/-
3. Inverter
6. Utility Bi-directional Meter. However, customer installs & owns meter socket.
1. Ameren is committed to both the safety of the public and its employees while maintaining
reliable operation of its distribution system. Installations involving customer-owned and
operated Distributed Energy Resources (DER) create the potential for serious personal injury
as well as damage to the Customer’s or Company’s equipment.
2. In order to minimize potential dangers to utility employees and the public, all DER
installations such as photovoltaic (PV), wind, energy storage systems (ESS), motor driven
generators, or other systems shall adhere to UL 1741 and the most current Ameren Illinois
approved version of IEEE 1547 as documented in the Ameren Illinois DER Customer
Interconnection Policy, and when applicable shall comply with the Illinois Smart Inverter
Rebate specifications, and any applicable requirements of the National Electrical Safety
Code, the National Electrical Code, Institute of Electrical and Electronics Engineers (IEEE),
Underwriters Laboratories (UL), Electrical Testing Laboratories (ETL), local electric codes,
applicable NEMA codes, OSHA, the AHJ, and Company’s Electric Service Rules as set
forth in published tariffs. The Illinois Smart Inverter Rebate specifications can be found in
the Illinois Distributed Generation Rebate Application. This document can be accessed from
the Distributed Generation link on the Ameren Illinois Renewables Resource Center
webpage.
3. Anti-islanding protection is required for all alternate (non-utility) sources of energy.
Anti-islanding protection is a way for the DER system to sense when there is an abnormal
condition on the utility grid, such as a power outage or other power quality issues. This
standard prevents the DER from injecting power back to the utility grid, which would create a
potentially hazardous condition for utility workers and the public. However, this requirement
shall not be construed to prevent the DER/ESS system from continuing to feed the
customer’s critical loads using automatic transfer switches, manual transfer switches, or
mechanical interlocks to prevent backfeed onto the utility grid.
4. For Behind-the-Meter (BTM) interconnections ≥ 200 kW, Ameren Illinois reserves the right to
require a non-revenue production meter to monitor DER generation. For ESS systems with
export capacity greater than 25 kW, Ameren Illinois reserves the right to require a revenue
grade meter to monitor the output of the ESS to ensure that exporting ESSs are only
charged by renewables (i.e. proper mode selection).
5. Careful selection of customer owned transformers and their protective equipment located on
the load side of main disconnecting means must be made to prevent excessive overheating
and to ensure detection of abnormal conditions such as Loss of Phase events. See ASM
Section 900. The consequences of not detecting the Loss of Phase condition would be a
violation of Standard IEEE 1547 as documented in the Ameren Illinois DER Customer
Interconnection Policy.
6. Customer's DER system must include a lockable AC generation source disconnect that is
operable and can be locked in the “OFF” position by Ameren Illinois personnel, Customer,
and emergency personnel. This disconnect switch will allow the DER system isolation from
Company's distribution facilities for maintenance, reliability, and safety concerns. Any HOLD
OFF tags or clearances given to the Customer's lockable AC generation source disconnect
must be honored by Ameren Illinois personnel, the Customer, and emergency personnel.
Refer to ASM Sections 1500.02.7 and 1500.02.8 for specific location requirements.
7. The lockable AC generation source disconnect shall be labeled by the customer with
permanent placarding stating: "LOCKABLE AC GENERATION SOURCE DISCONNECT.”
If the lockable AC generation source disconnect is greater than 10 ft from the revenue meter
or not within sight of the revenue meter, additional permanent placarding stating
“CAUTION: MULTIPLE SOURCES OF POWER – LOCKABLE AC GENERATION
SOURCE DISCONNECT AVAILABLE FOR ISOLATION FROM UTILITY” shall be installed
on the AC Generation Source Disconnect and the main service disconnect. If the main
service disconnect is not immediately visibly adjacent to the meter socket, an additional
placard with this language will also be required to be permanently adhered to the meter
socket, CT cabinet, or wall immediately adjacent. Placarding must also have additional
verbiage to explain the exact location of the AC Generation Source Disconnect. Most times,
there is a site overview map showing the facilities and identifying where the main service
disconnect and the AC generation source disconnect is located. The site overview map is
required to be attached to each of the above described locations.
a. Permanent placards must be engraved on hard plastic and adhered to the meter
socket lid and lockable AC generation source disconnect with permanent adhesive
or adhered to the building exterior surface immediately adjacent.
b. Use of a label maker or glued-on strips is not acceptable.
8. For an ESS integrated with DER installations, all premises must have a lockable ESS
disconnecting means on the AC side of the DER system for an AC coupled ESS or on the
DC side of the DER system for a DC coupled ESS, or its remote control, located at 1) a
readily accessible location outside the building and 2) within 10 feet of the Lockable AC
Generation Source Disconnect(s) and maintaining visibility. The ESS disconnecting means
shall be permanently placarded “ENERGY STORAGE SYSTEM DISCONNECT” or
“ENERGY STORAGE SYSTEM DISCONNECT – REMOTE CONTROL” (if remotely
actuated). The ESS disconnecting means must also have a permanent placard outlining the
operating characteristics listed in the 2020 NEC 706.15(C). The Energy Storage System
Disconnect or Energy Storage System Disconnect – Remote Control must be depicted on
the site overview map placard previously described, and the site overview map placard must
also be adhered to the enclosure or the wall immediately adjacent.
9. For an ESS serving a critical loads panel, an integral or external automatic transfer switch
(preferred), manual transfer switch, or mechanical interlock that allows transferring from the
utility source to the DER/ESS system and vice versa must be installed. This transfer switch
allows Ameren to disconnect utility power to the inverter by operating the lockable AC
generation source disconnect for completion of the witness test without interrupting power to
the critical loads panel. If the customer elects to install an ATS, the normal source should
be utility grid power. If a manual transfer switch or mechanical interlock kit is used, then the
critical loads panel must be served by utility grid power until the witness test is completed.
After the completion of a successful witness test, the customer or installer should swap the
manual transfer switch or mechanical interlock kit over so the normal feed is from the
inverter AC output.
10. If a PV installation is served by more than one lockable AC generation source disconnect,
then each disconnect must have a permanent placard depicting an aerial view of the
location (including the boundaries of the respective PV panel systems) and the location of all
lockable AC generation source disconnects. This placarding must identify how to de-
energize a particular section of PV generation in order to ensure the safety of personnel
working around the PV system and emergency responders. Additionally, each PV panel
system shall have uniquely identifiable permanent placards matching the respective lockable
AC generation source disconnect.
11. Customer DER systems must include appropriate wiring and metering equipment if the
customer wants to sell or receive credit for excess electricity generated by the DER being
injected back into the Ameren Illinois electric distribution system. The customer must file
an application, including a detailed one-line diagram (when applicable), so that the process
for interconnecting a proposed DER installation can begin.
12. Sales of electricity are regulated by various state and federal agencies, and it is the
customer's responsibility to investigate all state and federal agency requirements before
filing an application.
6. Customer's lockable AC generation source disconnect and lockable energy storage system
disconnect shall comply with the following:
a) One of the following types
1) Manual operable switch or circuit breaker
2) Load-break-rated pull-out-switch
b) Simultaneously disconnect all ungrounded conductors of the circuit.
c) Located outdoors where readily accessible.
d) Enclosures with doors or hinged covers that are readily accessible to unqualified
persons and have exposed live parts when the enclosure is opened must be
secured in a manner that requires a tool to open the enclosure or must be lockable.
e) Disconnect mechanism must be padlockable in the open (OFF) position.
f) Plainly indicate whether in the open (OFF) or closed (ON) position.
g) Have ratings sufficient for the maximum circuit current, available fault current, and
voltage that is available at the terminals.
h) Be marked with a warning when the line and load terminals are capable of being
energized in the open position.
i) The disconnect(s) must be within reach, with a maximum mounting height with the
handle no higher than 6'7" above grade when in the "UP" or ON position.
j) When the lockable AC generation source disconnect(s) or a line-side tapped
energy storage system AC disconnect is a knife-blade safety switch (fused or
non-fused), the conductors coming from the DER system must terminate on the
bottom lugs of this disconnect. Utility supply will terminate on the top lugs of this
disconnect.
k) When the lockable AC generation source disconnect(s) or a line-side tapped
energy storage system AC disconnect is a Circuit Breaker, the utility supply shall
terminate at the ON side lugs of the breaker. The conductors coming from the DER
system shall terminate at the OFF side lugs of the breaker.
7. A LOAD SIDE TAP is when the DER connects downstream of the customer's main service
disconnect. The lockable AC generation source disconnect will be located outdoors,
readily accessible, within 10 ft of the electric revenue meter, and between the inverter and
a circuit breaker or fuse (overcurrent protection device - OCPD) located in the main
distribution panel. This disconnect may or may not have overcurrent protection in this
device. The maximum size of the proposed DER system is limited by the main service
disconnect ampere rating, associated bus rating, and overcurrent protection device rating.
Taking these values into account, the maximum size of the DER system can be
calculated per NEC requirements.
The lockable AC generation source disconnect must have an equipment grounding
conductor that originates at the main service disconnect and terminates on the enclosure.
The lockable AC generation source disconnect may have the following depending upon
system configuration:
a) System neutral
b) Overcurrent protection
8. A LINE (SUPPLY) SIDE TAP is when DER interconnections are made between the
customer's main service disconnect and Ameren's metering instruments or self-contained
meter. A Line Side Tap requires a DER Main Disconnecting Means with overcurrent
protection, similar as the Main Service Disconnecting Means. In some cases, the DER
Main Disconnecting Means may also serve as the lockable AC generation source
disconnect switch. When the lockable AC generation source disconnect is located
downstream of the DER Main Disconnecting Means, the lockable AC generation source
disconnect switch may or may not have over-current protection in this device. The
lockable AC generation source disconnect must be outdoors, readily accessible, and
mounted within 10 feet and in sight of the electric revenue meter. If this distance cannot
be maintained – consult with your Ameren representative. The size of the proposed DER
installation is limited by the ampere ratings of the service entrance conductors, metering
equipment, and other service equipment ratings.
9. LINE (SUPPLY) SIDE TAP POINT OF INTERCONNECTION (POI) must comply with the
following requirements:
a) Conductors running from the POI to the DER Main Disconnecting Means and
overcurrent protection device shall be no smaller than #6 AWG copper or #4 AWG
aluminum.
b) The conduit running from the POI to the DER Main Disconnecting Means shall
contain only DER service entrance conductors. Monitoring cables and other
customer circuitry are not permitted.
c) If the customer chooses to install a production meter, it must be located after the
DER Main Disconnecting Means (i.e. on the generator side).
d) Where the DER circuit makes a POI outside of a building or at a meter structure
(OH or UG), it shall be protected by an overcurrent device(s) at a readily
accessible location outside the building, near a meter structure, or where the DER
conductors enter the building. The overcurrent protection device shall be located
within one of the following criteria:
1) 15 ft of total conductor length from POI for dwelling units,
2) 20 ft of total conductor length from the POI for meter structures,
3) 20 ft horizontally or 30 ft of total conductor length (if bends are required)
from the POI for buildings which are not considered to be dwelling units.
*If current limiters are installed, the total conductor length can be extended
by up to 41 ft for each category above, but in no instance shall unprotected
conductors extend more than 10 ft into a building.
e) Where the DER installation makes its POI to a service inside a building, they shall
be protected by one of the following methods:
1) with an overcurrent device located within 10 ft of conductor length in
dwelling units and 16.5 ft in other than dwelling units from the point of
connection to the service.
2) in other than a dwelling unit, with an overcurrent device located within 71
ft of conductor length from the point of connection to the service, provided
that cable limiters installed in all ungrounded conductors are located
within 16.5 ft of conductor length from the point of connection to the
service.
h) POI can be made in a junction box, trough, or tap box after the metering equipment
but before the main service disconnect. DER POI must be made using listed
connectors and comply with NEC enclosure fill requirements. All power distribution
blocks installed on service conductors shall be marked as "Suitable For Use On
Line Side of the Service Disconnect." Effective January 1, 2023, pressure
connectors and devices for splices and taps installed on service conductors shall
be marked as "Suitable For Use On Line Side of the Service Disconnect." 2020
NEC 230.46
u) When making a line side tap where the DER Main Disconnecting Means will be
mounted on a separate structure from the service installation and these structures are
not mechanically secured together to function as a single structure, then the supply
conductors from the POI at the service installation to the DER Main Disconnecting
Means must be run underground in a conduit system.
For a main service disconnect & DER Main Disconnecting Means mounted on separate
structures, the DER Main Disconnecting Means must be mounted on a building or
galvanized metal structure similar to as shown in ASM Section 700 figures.
10. When making a Line (Supply) Side Tap from a service installation that is served from a
grounded secondary utility system, the DER main disconnecting means must have the
grounded (neutral) conductor run from the POI and properly terminated/grounded, even
if Customer DER system does not require the grounded (neutral) conductor.
*A unipot transformer is a transformer that contains all three phases within the same tank.
This includes both overhead and padmount transformers.
**Aggregate DER refers to the sum of all such DER installations connected in the same
manner to a common transformer.
IEEE SMART Inverters connected to the Utilities systems shall be rated as compliant
1547- with the most current Ameren Illinois approved version of IEEE 1547 as
2003/2018 documented in the Ameren Illinois Smart Inverter Specifications document.
IF applying for the Illinois SMART Inverter rebates, SMART inverters shall meet additional
requirements stated in Rider CGR.
Interconnection Resources
2) PowerClerk https://amerenillinoisinterconnect.powerclerk.com/MvcAccount/Login
**This is the preferred application method.
Level Description
1 Lab-certified, inverter-based interconnection equipment with an aggregate electric
nameplate capacity less than or equal to 50 kW and a maximum export capacity
of 25 kW.
2 Lab-certified interconnection equipment with an aggregate electric nameplate
capacity greater than 25 kW and less than or equal to 5 MW. Lab certified is
defined in 466.30.
3 DER facility does not export power utilizing an export control listed in 466.75. For
connections to area or sport networks, nameplate capacity rating of all aggregate
generation on the network is less than or equal to the lesser of 50 kVA or 5% of
the network's maximum loading. For radial distribution circuits, the aggregate
export capacity of all generation (existing and proposed) on the circuit must be no
greater than 10 MVA or less than or equal to 10 MVA if connecting to a radial
distribution feeder.
4 Nameplate capacity rating is less than or equal to 10 MVA and
the distributed generation facility does not qualify for a Level 1, Level 2, or Level
3 review, or the distributed generation facility has been reviewed but not
approved under a Level 1, Level 2, or Level 3 review. Any generation larger
than 10 MVA would be covered by 83 Ill. Adm. Part 467.
For a complete list of criteria and most current tariff filings, please refer to 83 Ill. Adm. Part 466,
Electric Interconnection of Distributed Energy Resources Facilities, which can be found at the
following link: https://www.ilga.gov/commission/jcar/admincode/083/08300466sections.html.
Level 2 and Level 4 BTM DER interconnections for which the Ameren Illinois planning analysis
requires system upgrades: Metering interval data, provided by Ameren Illinois, will be required
for at least one year, or if the customer is new, detailed operating load information will be
required to be provided by the customer for proper transformer and other Ameren Illinois
equipment evaluation (sizing and charges). If larger equipment is required to serve the DER
than is required to serve the load, the customer will be required to pay the difference without
the benefit of delivery service revenue credit. A functional one-line must be submitted by the
customer to enable Ameren Illinois to perform the analysis.
DER interconnections to the Ameren Illinois secondary spot and grid networks found in
Bloomington, Decatur, and Peoria are subject to Level 3 review. Due to operational
complexities of network protectors found on the secondary spot and grid network systems,
Level 3 interconnections SHALL NOT export (backfeed) power on the Ameren Illinois
distribution system. It is the customer's responsibility to install appropriate equipment to ensure
the DER installation will adhere to the NO EXPORT criteria of the Interconnection Agreement
with Ameren Illinois. As part of the Level 3 process, Ameren Illinois must conduct a thorough
engineering review of the DER interconnection application that requires interval demand
information from the customer for the previous 12 months. If Ameren Illinois does not have the
interval demand history, the customer will be responsible for all costs to install an advanced
revenue metering package to obtain this data.
Access to Premises
Ameren Illinois may enter Customer’s premises without prior notice:
1. to, at all reasonable hours, inspect Customer’s DER and protection devices and read
or test any meter for the Facility.
2. to disconnect, at any time, without notice, the Facility, if in Ameren Illinois’ sole
opinion, a hazardous condition exists and that immediate action is necessary to
protect persons, or Ameren Illinois’ facilities, or property of others from damage or
interference caused by
a) Customer’s Facility or
b) Customer’s failure to comply with the requirements of this Agreement
3. to take monthly readings of the bidirectional digital meter for billing purposes.
Self-reads and reads from adjacent properties are not permitted.
1500.05 METERING
1. Parallel generating facilities connected to Company's system are divided into two groups:
a) Non-exporting DER would apply to Customer's facilities whose load is
significantly larger than their generating capacity so that no Customer generated
power would flow into Company's system except under fault conditions. This
metering scenario also applies to DER systems that are not allowed to export
due to interconnection with Company's secondary spot and grid networks.
A Smart Inverter is a device that converts direct current into alternating current and can
autonomously contribute to grid support during deviations from normal operating voltage and
frequency conditions by providing each of the following: dynamic reactive and real power
support, voltage and frequency ride-through, ramp rate controls, communication systems with
ability to accept external commands, and other functions from the electric utility.
Smart Inverters are distinguished from inverters without smart capabilities in three ways:
1. They can modify their real power (Watts) and reactive power (VARs) output to provide grid
support.
2. They can respond autonomously to voltage/frequency changes.
3. They can respond to communication signals.
1. Parallel Generator
2. DC Disconnect
6. Ameren Bi-directional
Meter
3. SMART Inverter
Device/Gateway
1. Parallel Generator
2. DC Disconnect
6. Ameren Bi-directional
Meter
3. Inverter