Ansi C12.1-2001
Ansi C12.1-2001
Ansi C12.1-2001
1=2001
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Secretariat
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The American National Standards Institute does not develop standards and will in no
circumstances give an interpretation of any American National Standard. Moreover,
no person shall have the right or authority to issue an interpretation of an American
National Standard in the name of the American National Standards Institute.
Requests for interpretations should be addressed to the secretariat or sponsor
whose name appears on the title page of this standard.
Published by
O Copyright 2001 by the National Electrical ManufacturersAssociation. All rights including translation into
other languages, reserved under the Universal Copyright Convention, the Berne Convention for the
Protection of Literary and Artistic Works, and the Internationaland Pan American Copyright Conventions.
No part of this publication may be reproduced in any form, in an electronic retrieval system or otherwise without prior Mtten permission
of the publisher.
TABLE OF CONTENTS
Foreword
2 Definitions ............................................................................................................................................. 2
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5.3.3.3 Heavy burden test ................................................................................... 54
5.3.3.4 Secondary voltage test ............................................................................ 54
5.4 Coupling-capacitor voltage transformers ................................................................................ 55
5.4.1 Performance tests ................................................................................................ 55
APPENDIX A ............................................................................................................................................... 60
A.l Measurement of power ........................................................................................................... 60
A . l . l Introduction........................................................................................................... 60
A.1.2 Blondel's theorem ................................................................................................. 60
A.1.3 Direct-current circuits ........................................................................................... 60
APPENDIX 6...................................................................................................... 69
B.l General ................................................................................................................................... 69
B.2 Final authority ......................................................................................................................... 69
B.2.1 Electrical units ...................................................................................................... 69
B.3 National standards .................................................................................................................. 70
B.3.1 Standard of resistance.......................................................................................... 70
B.3.2 Standard of electromotive force............................................................................ 70
B.3.3 Other electrical standards..................................................................................... 70
B.3.4 Standard of time interval....................................................................................... 70
8.4 Establishing a local reference standard of energy .................................................................. 70
B.4.1 Meter laboratory ................................................................................................... 72
B.4.2 Meter shop............................................................................................................ 72
8.4.3 Independent standards laboratory........................................................................ 72
B.5 Laboratory conditions ............................................................................................................. 72
8.5.1 Reference temperature and humidity ................................................................... 72
B.5.2 Laboratory power sources .................................................................................... 73
B.6 Laboratory reference standards.............................................................................................. 73
B.6.1 Stability of reference standards ............................................................................ 73
8.6.2 Basic reference standards..................................................................................... 73
B.6.2.1 Intercomparison....................................................................................... 73
8.6.3 Transport standards ............................................................................................. 73
B.6.4 Voltage references ............................................................................................... 74
8.6.4.1 Standard cells .......................................................................................... 74
B.6.4.2 Unsaturated standard cells ...................................................................... 74
8.6.4.3 Solid-state voltage standards ................................................................... 74
B.6.5 Standard resistors ................................................................................................ 74
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ANSI C12.1-2001
Page ix
Appendix C .................................................................................................................................................. 89
C.l General ................................................................................................................................... 89
C.2 Symbols .................................................................................................................................. 89
C.3 Shaft reduction........................................................................................................................ 89
C.4 Formulas................................................................................................................................. 89
APPENDIX D ............................................................................................................................................... 91
APPENDIX E ............................................................................................................................................... 93
E.l Definition................................................................................................................................. 93
E.2 Types defined ......................................................................................................................... 93
APPENDIX F ............................................................................................................................................... 95
F.l Preface to the First Edition (1910) .......................................................................................... 95
F.2 Preface to the Second Edition (1922) ..................................................................................... 96
F.3 Preface to the Third Edition (1928) ......................................................................................... 96
F.4 Preface to the Fourth Edition (1941)....................................................................................... 97
F.5 Preface to the Fifth Edition (1965) .......................................................................................... 98
F.6 Preface to the Sixth Edition (1975) ......................................................................................... 99
F.7 Foreword to the Seventh Edition (1982) ............................................................................... 100
F.8 Foreword to the Eighth Edition.............................................................................................. 102
New to this edition is a methodology for certification of new meter types, which was deemed necessary
because of the more rapid development of meter technology. Other significant additions are specific tests for
meter ancillary devices and tests for wide voltage range meters. Most meter specifications have been
retained from the previous edition without major changes.
The existing standard was broadened to include tests and requirements for all meters, both solid state and
electromechanical. Other standards in the C I 2 series provide the details for their specific devices, thus
avoiding duplication. In addition, an effort was made to align this standard with modern international
standards for electromagnetic compatibilitywhere possible.
The Secretariat of the Accredited Standards Committee on Electricity Metering, (212, is held by the National
Electrical Manufacturers Association (NEMA) and the National Institute of Standards and Technology. At the
time this standard was processed and approved, the CI2 Committee had the following members:
The following members of the C12 Ad Hoc Committee to Revise C12.1 were actively involved in the
revision of this standard:
C. Weikel, Chairman
M. Anderson
J. Arneal
W. Buckley
Ma.Burns
B. Cook
J. DeMars
W. Germer
C. Gomez
R. Lokys
E. Malemezian
S. Malich
K. McDonald
J. McEvoy
H. Millican
T. Morgan
D. Nguyen
L. Pananen
G. Powers
M. Purc
J. Ruehl
J. Taylor
J Thurber
T. Vahlstrom
S. Weikel
C. S. Weimer
D. Williams
In addition, the following comprised the Editorial Committee for the current Revision of C12.1:
M. Anderson
M. Keys
E. Malemezian
K. Masri
H. Millican
S. Weikel
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This Code establishes acceptable performance criteria for new types of ac watthour meters, demand meters,
demand registers, pulse devices, and auxiliary devices. It describes acceptable in-service performance levels
for meters and devices used in revenue metering. It also includes information on related subjects, such as
recommended measurement standards, installation requirements, test methods, and test schedules. This
Code for Electricity Metering is designed as a reference for those concerned with the art of electricity
metering, such as utilities, manufacturers, and regulatory bodies.
1.2 References
The following publications shall be used in conjunction with this standard. When they are superseded by an
approved revision, the revision shall apply:
ANSI C39.1-1992, American National Standard Requirements for Electrical Analog Indicating Instruments
Chapter 13 in the Handbook for Electricity Metering, 9th Edition, Washington, D.C.: Edison Electric Institute,
1992
ASQ Z1.9-1993, Sampling Procedures and Tables for Inspection by Variables for Percent Nonconforming.
ASQ 21.4-1 993, Sampling Procedures and Tables for Inspection by Attributes
IEEE Std 100-1996, IEEE Standard Dictionary of Electrical and Electronics Terms
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ISA 82.01-1994, Safety Standard for Electrical and Electronic Test, Measuring, Controlling and Related
Equipment, General Requirements
UL 50-1995, UL Standard for Safety Enclosures for Electrical Equipment, 71th Edition
ASTM B117-97, Standard Practice for Operating Salt-Spray (Fog) Testing Apparatus
IEEE Std 1-1986, IEEE Standard General Principles for Temperature Limits in the Rating of Electric
Equipment and for the Evaluation of Electrical Insulation. (Reaffirmed 7992)
IEEE C37.90.1-1989, Standard Surge Wdhstand Capability (SWC) Tests for Protective Relays and Relay
Systems (Reaffirmed 1991)
IEEE C62.41-1991, IEEE Recommended Practice on Surge Voltages in Low-Voltage AC Power Circuits
IEC 61000 part 4-4 (1995), Electromagnetic Compatibility for Industrial - Process Measurement and
Control Equipment, Part 4: Electrical Fast TransienüBurstRequirements
IEC 60068 part 2-6 (1995), Basic EnvironmentalTesting Procedures, Part 2: Tests, Test Fc and
Guidance: Vibration (Sinusoidal)
Code of Federal Regulations (Telecommunication) CFR 47, Part 75-RadiO Frequency Devices, Subparts
A-General and &Unintentional Radiators
IEC 61000 part 4-2 Edition 1.i(1999), Electromagnetic Compatibility for Industrial - Process Measurement
and Control Equipment, Part 2: Electrostatic Discharge Requirements
International Safe Transit Association, Test Procedure 7A, Performance Test for Individual Packaged-
Products Weighing 750 lb. (68 kg) or Less, (revision date: July 2000) , Vibration and Shock
IEC 60068 part 2-27 (1987), Basic Environmental Testing Procedures, Pad 2: Tests, Test Ea and Guidance:
Shock.
ASTM G155 1998, Standard Practice for Operating Xenon Arc Light Apparatus for Exposure to Non-
Metallic Materials
2 Definitions
The definitions given apply specifically to the subject as treated in this American National Standard. Most of
them are grouped under general terms, such as watthour meter, and all are given numbers for identification.
For additional definitions, see IEEE Std 100.
2.1 accuracy: The extent to which a given measurement agrees with the defined value.
2.2 auxiliary device: An add-on device mounted under the meter cover that adds functionality to the
meter device.
2.3 Blondel's theorem: In a system of N conductors, N-1 meter elements, properly connected, will
measure the active power or energy taken. The connection must be such that all voltage coils have a
common tie to the conductor in which there is no current coil.
2.4 calibration: Comparison of the indication of the instrument under test, or registration of the meter
under test, with an appropriate standard.
2.5 certified meter type: A metering device which is tested and certified to meet the certification testing
as specified in this standard for a specific meter type. It shall include any optional circuit boards, devices, or
modules enclosed within the meter cover as part of this certified meter type.
2.8 creep: A continuous apparent accumulation of energy in a meter with voltage applied and the load
terminals open circuited.
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0 2.10 demand: The average power or a related quantity over a specified interval of time. Demand is
expressed in kilowatts, kilovolt-amperes, kilovars or other suitable units.
2.11 demand constant (pulse receiver K.,): The value of the measured quantity for each received pulse,
expressed in kilowatts per pulse, kilovars per puise, or other suitable units.
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2.12 demand interval: The specified interval of time on which a demand measurement is based.
Intervals such as 15,30,or 60 minutes are commonly specified.
2.13 demand interval deviation: The difference between the measured demand interval and the
specified demand interval, expressed as a percentage of the specified demand interval.
2.14 -
demand interval rolling (RDI): An interval of time, the beginning which progresses in steps of
sub-intervals and where the interval length is equal to an integer multiple of sub-intervals.
2.15 demand-maximum: The highest demand measured over a selected period of time.
2.17 demand meter - block interval (integrating): A meter that integrates power or a related quantity
over a fixed-time interval, and indicates or records the average.
2.18 demand meter- lagged: A demand meter with an approximately exponential response.
2.19 demand meter (lagged) - time characteristic: The nominal time required for 90% of the final
indication, with constant load suddenly applied.
NOTE-The time characteristic of demand meters (lagged) describes the exponential response of the meter to the applied load. The
response is continuous and independentof the selected discrete time intervals.
2.20 demand register: A device for use with an electricity meter, that indicates and/or records demand.
2.21 -
demand register block interval: A demand register that indicates andlor records the maximum
demand obtained by arithmetically averaging the meter registration over a regularly repeated time interval.
2.22 -
demand register continuous cumulative: The sum of all previous billing period maximum
demands and the highest demand to date for the present billing period.
2.23 -
demand register cumulative: A register that indicates the sum of the previous maximum demand
readings prior to reset.
NOTE-When reset, the present reading is added to the previously accumulated readings. The maximum demand for the present
reading period is the difference between the present and previous readings.
2.24 demand register - indicating single-pointer form: An indicating demand register from which the
demand is obtained by reading the position of a pointer relative to the markings on a scale.
NOTE-When reset, the single pointer retumc to zero.
2.25 -
demand register dual range (single pointer form): An indicating demand register having an
arrangement for changing the full-scale capacity from one value to another, usually by reversing the scale
plate.
e NOTE-For example, Scale Class 1/2; Scale Class 2í6.An interlock assures proper scale and scale-ciass relation.
2.26 -
demand register full-scale value: The maximum scale capacity of the register. If a multiplier
exists, the full-scale value will be the product of the maximum scale marking and the multiplying constant.
2.27 -
demand register scale class: Denotes, with respect to single-pointer form, dual-range single-
pointer form, or cumulative-form demand registers, the relationship between the full-scale value of the
register and the test kVA rating of the meter with which the register is used.
2.28 display: A means of visually identifying and presenting measured or calculated quantities and other
information.
2.29 electricity meter: A device that measures and registers the integral of an electrical quantity with
respect to time.
2.30 electronic register - alternate mode: A display sequence usually containing constants and
diagnostic tests.
2.31 electronic register - load control: A switching control for external load management.
2.32 -
electronic register test mode: A separately activated sequence that saves billing data while
displaying test data. It reactivates the billing data to the register when the normal mode is resumed.
2.33 element: An element is the combination of signal sensing units, resulting in an output proportional to
the measured quantities.
NOTES
1 For example, if one input signal is voltage and the other input signal is current, then the output is power (watts).
2 The term element is also referred to as stator.
3 Electricity meters nomially include 1,2,2-1/2, or 3 elements.
4 The 2-1/2 element meter refers to 2 stator 4-wire wye meter as described in section A2.7.2.
2.34 electronic storage register: An electronic circuit where data is stored for display and/or retrieval.
2.35 endof-interval indicator (EOI): An indicator for the end of the demand interval for non-rolling
(block)-intervaldemand, or the end of the sub-interval for rolling-interval demand.
2.37 energy flow: Energy flow from line to load terminals shall be considered as energy delivered to the
load terminals of the meter. Energy in the opposite direction, ¡.e., from load to line terminals, shall be
considered as received. The line and load terminals are as specified in the Handbook forElecfnCity Metering
(Chapter 13).
2.38 firmware: A control program stored in read-only memory (ROM)and considered to be an integral
part of an electronic device that cannot be changed in its operating environment.
2.39 homogeneous meter group: A lot or population of meters from which a random sample is selected
that, as far as is practicable, consists of meters of the same basic type or model designation, have the same
general construction, produced by the same manufacturer, and have the same relationship of parts.
2.40 interface: The means for transmitting information between the meter or register and peripheral
equipment.
2.41 -
laboratory meter: A laboratory responsible for maintaining reference standards and assigning
values to the working standards used for the testing of electricity meters and auxiliary devices.
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2.42 -
laboratory independent standards: A standards laboratory maintained by, and responsible to, a
company or authority that is not under the same administrative control as the laboratories or companies
submitting instruments for calibration.
2.43 metering devices: Equipment used in energy revenue metering; such as watthour meters, demand
meters, demand and TOU registers and various forms of pulse initiating, receiving and totalizing devices.
2.44 normal mode: The operating mode of the register usually displaying the billing data.
2.46 phasor: A complex number, associated with sinusoidally varying electrical quantities, such that the
absolute value (modulus) of the complex number corresponds to either the peak amplitude or rms value of
the quantity, and the phase (argument) to the phase angle at zero time. By extension, the term "phasor" can
also be applied to impedance and related complex quantities that are not time-dependent.
2.47 -
power active: The time average of the instantaneous power over one period of the wave.
NOTE-For sinusoidal quantities in a two-wire circuit, it is the product of the voltage, the current, and the cosine of the phase angle
between them. For nonsinusoidal quantities, it is the sum of all the harmonic components, each determined as above. In a
polyphase circuit, it is the sum of the active powers of the individual phases.
2.48 -
power apparent: The product of rms current and rms voltage for any wave form in a two-wire
circuit. For sinusoidal quantities, apparent power is equal to the square root of the sum of the squares of
the active and reactive powers in both two-wire and polyphase circuits.
2.49 -
power reactive: For sinusoidal quantities in a two-wire circuit, reactive power is the product of the
voltage, the current, and the sine of the phase angle between them, using the current as reference. '
2.50 power factor: The ratio of active power to the apparent power.
2.51 precision: The repeatability of measurement data, customarily expressed in terms of standard
deviation.
2.52 pulse: A change of state of an electrical signal that conveys an event or information.
NOTE-A sudden change of voltage or current produced, for example, by the closing or opening of a contact.
2.53 pulse amplifier or relay: A device used to change the amplitude or waveform of a pulse for
retransmissionto another pulse device.
2.54 pulse capacity: The number of pulses per demand interval that a pulse receiver can accept and
register without loss.
2.55 pulse device (for electricity metering): The functional unit for initiating, transmitting, retransmitting,
or receiving electric pulses, representing finite quantities, such as energy, normally transmitted from some
form of electricity meter to a receiver unit.
2.56 pulse initiator: Any device, mechanical or electrical, used with a meter to initiate pulses, the number
of which are proportional to the quantity being measured. It may include an external amplifier or auxiliary
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2.57 puise-initiator output constant (K, or W H C ) : The value of the measured quantity for each
outgoing pulse of a pulse initiator, expressed in kilowatt hours per pulse, kilovarhours per pulse, or other
suitable units.
2.58 puise-initiator output ratio (RIP or M,,): The number of revolutions of the meter rotor per output
pulse of the pulse initiator.
2.59 puise rate - maximum: The number of pulses per second at which a pulse device is nominally
rated.
2.60 pulse receiver: The unit that receives and registers the pulses.
2.61 puise recorder: A device that receives and records pulses over successive demand intervals.
2.62 puise-recorder channel: One individual input, output, and intervening circuitry required to record
pulse data.
2.63 Q-hour meter: An electricity meter that measures the quantity obtained by effectively lagging the
applied voltage to a watthour meter by 60 degrees. This quantity is used with watthours in calculating
quadergy (varhours).
2.65 shop - meter: A place where meters are inspected, repaired, tested, and adjusted.
2.66 simulated meter: A meter cover, base, and jumper bars constructed to represent the thermal
characteristics of a specific class of watthour meter to be used in the testing of a meter socket and in
determining the empirical temperature rise of the test meter for temperature rise at continuous ampere rating.
2.67 -
standards national: Standard electrical quantities that are maintained by the National Institute of
Standards and Technology (NIST).
2.68 -
standard watthour meter basic current range: The current range of a multirange standard
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watthour meter designated by the manufacturer for its calibration (normally the 5 A range).
2.69 -
standard watthour meter basic voltage range: The voltage range of a multirange standard
watthour meter designated by the manufacturer for its calibration (normally the 120 V range).
2.70 standard watthour meter - rated current: The nameplate current for each range of a standard
watthour meter.
NOTE-The main adjustment of the meter is ordinarily made with rated current on the basic current range.
2.71 standard watthour meter - rated voltage: The nameplate voltage for a meter or for each range of
a standard watthour meter.
NOTE-The main adjustment of the standard meter is ordinarily made with rated voltage on the basic voltage range.
2.72 -
test acceptance: A test to demonstrate the degree of compliance of a device with the purchaser's
requirements.
2.73 -
test accuracy in-service: A test made during the period that the meter is in service. It may be
made on the customer's premises without removing the meter from its mounting, or by removing the meter
for test either on the premises or in a laboratory or meter shop.
2.74 - -
test accuracy referee: A test made by or in the presence of one or more representatives of a
regulatory body or other impartial agency.
2.75 - -
test accuracy request: A test made at the request of a customer.
2.76 test amperes (TA): The load current specified by the manufacturer for the main calibration
adjustment.
2.77 test - approval: A test of one or more meters or other items under various controlled conditions to
ascertain the compliance of the type of which they are a sample with the appropriate standard.
2.78 timebase primary: A timing system established from the frequency of the power line or other
referencesource.
2.79 timebase secondary: A timing system established from an alternate source when the primary
source is not available.
2.80 timeof-use register: That portion of a watthour meter that, for selected periods of time,
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accumulates and may display amounts of electric energy, demand, or other quantities measured or
calculated.
2.81 -
timeof-use register period: A selected period of time during which a specified rate will apply to
the energy usage or demand, typically designated as A, B, C, and D.
2.82 -
time-of-use register switch point: The transition from one time-of-use period to another.
2.83 total harmonic distortion (THD): The ratio of the root-mean-square of the harmonic content
(excluding the fundamental) to the root-mean-square value of the fundamental quantity, expressed as a
percentage.
2.84 totalizing: A device used to receive and sum pulses from two or more sources for proportional
transmission to another totalizing relay or to a receiver.
2.85 transducer: A device to receive energy from one system and supply energy (of either the same or
of a different kind) to another system, in such a manner that the desired characteristics of the energy input
appear at the output.
2.86 transformer-loss compensation: A method that adds to or subtracts from the meter registration to
compensate for predetermined iron and/or copper losses of transformers and transmission lines.
2.87 varhour meter: An electricity meter that measures and registers the integral, with respect to time, of
the reactive power of the circuit in which it is connected. The unit in which this integral is measured is usually
the kilovarhour.
2.88 varhour test constant: The expression of the relation between the reactive energy applied to the
meter and corresponding value of the test output.
NOTE-For electromechanical meters, one test output equals one disk revolution.
2.89 voltage-withstand tests: Tests made to determine the ability of insulating materials and spacings to
withstand specified overvoltages for a specified time without flashover or puncture.
2.90 watthour meter: An electricity meter that measures and registers the integral, with respect to time,
of the active power of the circuit in which it is connected. The unit in which this integral is measured is usually
the kilowatthour.
2.91 -
watthour meter bottomconnected:A meter having a bottom-connectedterminal assembly.
2.92 watthour meter - calibration: Adjustment to bring the percentage registration of the meter to within
specified limits.
2.94 watthour meter- class designation: The maximum specified continuous load in amperes.
2.95 watthour meter - detachable (socket mounted): A meter having bayonet-type (blade) terminals
arranged on the back side of the meter for insertion into matching jaws of a meter socket (or detachable
meter-mounting device).
2.96 -
watthour meter field standard: A portable meter that is used as a standard meter to calibrate the
utility’s billing meters and is traceable to NIST. This meter is also known as a portable standard or working
standard.
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2.97 watthour meter - form designation: An alphanumeric designation denoting the circuit
arrangement for which the meter is applicable and its specific terminal arrangement. The same designation is
applicable to equivalent meters of all manufacturers.
2.98 watthour meter - full load: Full load is a test condition using test amps, rated voltage and unity
power factor.
2.99 watthour meter - gear ratio (RJ: The number of revolutions of the meter’s rotor for one revolution
of the first dial pointer.
-
2.100 watthour meter induction: A motor-type meter in which currents induced in the rotor interact with
magnetic fields to produce the driving torque.
2.101 watthour meter - light load: Light load is a test condition using rated voltage, 10% of test amps
and unity power factor.
-
2.102 watthour meter load range: The maximum range in amperes over which the meter is designed to
operate continuously with a specified accuracy.
2.103 watthour meter - multistator:A watthour meter containing more than one stator
2.1 04 watthour meter - percentage error: The difference between percentage registration and 100%.
NOTE-A meter whose percentage registration is 95% is said to be 5% slow, or its error is (-) 5%.
-
2.105 watthour meter percentage registration: The ratio of the actual registration of the meter to the
true value of the quantity measured in a given time, expressed as a percentage.
-
2.106 watthour meter reference performance: test, used as a basis for comparison with performances
under other conditions of the test.
-
2.107 watthour meter register: A device for use with an electricity meter that indicates or records units
of electric energy or other quantity measured.
-
2.108 watthour meter register constant (KJ: The multiplier used to convert the register reading to
kilowatthours (or other suitable units).
NOTE-This constant takes into consideration the watthour constant, gear ratio, and instrument transformer ratios.
0 -
2.109 watthour meter register ratio (RJ: The number of revolutions of the first gear of the register for
one revolutionof the first dial pointer.
-
2.110 watthour meter registration: The amount of electric energy (or other quantity being measured)
that was recorded by the meter.
NOTE-It is equal to the product of the register reading and the register constant. The registration during a given period is equal to the
product of the register constant and the difference between the register readings at the beginning and the end of the period.
2.111 watthour meter - rotor: That pari of an induction meter that is directly driven by electromagnetic
action.
-
2.112 watthour meter self contained: A meter in which the terminals are arranged for connection to the
circuit being measured without using external instrument transformers.
2.113 -
watthour meter single stator: A meter containing only one stator.
2.114 watthour meter - stator: An assembly of an induction watthour meter, which consists of a voltage
circuit, one or more current circuits, so arranged that their joint effect, when energized, is to exert a driving
torque on the rotor.
-
2.115 watthour meter transport standard: Standard meters of the same or better level of uncertainty
as the basic reference standard meters that are used for transferring the value of the watthour between
standards.
2.117 watthour meter constant (K,,): The expression of the relationship between the energy applied to
the meter and one disk revolution or equivalent, expressed as watthours per revolution or watthours per
equivalent revolution.
3.1 Scope
To outline an appropriate chain of intermediate steps between the national standards and watthour meters.
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the billing meter and the national standard. Described below are some common methods for establishing this
traceability.
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NIST
Independent Lab
4
Basic Reference Standard
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Transport ............................................................................................................................................................. ...............<......
Standard
FieldMlorkinglPortable Standard
1
ICustomers Meter I
Figure B.l -Traceability Path Diagram
It may be equipped and staffed to make calibration tests at some or all of the sequential steps intermediate
between the national standards of resistance, EMF, and time interval, and-a local reference standard of
energy measurement (such as a group of watthour meters).
Alternating current supplies should be substantially free from waveform distortion, and the phase relation of
combined current and voltage supplies should be capable of close regulation.
e 3.1O
3.10.1 General test conditions
Performance requirements for standard watthour meters
The standard meter under test shall be in good operating condition and have established adequate records
for performance. The stability can be established through manufacturer's specifications or can be established
through historical test records.
The insulation between current-carrying parts of separate circuits and between current-carrying parts and
other metallic parts shall be capable of withstanding the application of a sinusoidal voltage of 2.3 kV n s , 60
Hz for 1 minute with the leakage current not to exceed 0.005 A per circuit.
3.10.2.2 Accuracy specification for the effect of variation of voltage and current
3.10.2.2.1 Reference conditions
Voltage 120v
Current 5.0 A
Frequency 60 Hz
Power Factor Unity and 0.5 Lagging
Temperature 23OC
4.1 General
4.1.1 Acceptable metering devices
New types of metering devices, in order to be acceptable, shall conform to requirements specified in 4.7
which are intended to determine their reliability and acceptable accuracy insofar as these qualities can be
demonstrated by laboratory tests.
Metering devices selected for certification testing shall be representative of production run metering devices.
All conditions of a specific test must must be applied to each test metering device.
4.3.2 Enclosures
The enclosure, if intended for indoor application, shall meet the performance specifications described in
NEMA Standards Publication 250, for Type 2 enclosures. If intended for outdoor application, enclosures shall
meet the performance specifications for Type 3R enclosures described in the same publication.
All leads and terminals shall be identified either on the device or in manufacturer's literature. For pulse
initiatorsonly one KYZ relay should have leads with the following color code:
-K=red
- Y = yellow
- 2 = black
4.3.4 Construction and workmanship
Metering' devices shall be substantially constructed of good material in a workmanlike manner, with the
objective of attaining stability of performance and sustained accuracy over long periods of time and over wide
ranges of operating conditions with a minimum of maintenance.
a) Different current ratings-there shall be one device of each of the representative current ratings.
b) Different voltage ratings-there shall be one device of each of the representativevoltage ratings.
c) Different number of elements-there shall be one device of each representative number of
elements.
d) Four-wire-wye and four-wire delta metering devices of the two-element type-there shall be one
device for each configuration.
An auxiliary device used on a previously approved metering device should be tested per the standard for only
those tests applicable to the auxiliary device. The previously approved metering device should be tested for
those Performance tests affected by the auxiliary device.
4.5.2 Configuration
Metering devices shall be complete assemblies.
a) Volt-square-hour devices shall be tested at 80%, 1OO%, and 120% of nameplate voltage.
b) Devices used to measure quantities, such as varhours or Q-hours, may be tested in accordance
with the test specifications for watthour metering devices, insofar as the tests apply.
--`,`,````,,`,,,,,,`,,,,,```,`,-`-`,,`,,`,`,,`---
When devices with voltage ratings encompassing more than one of the rated voltages of 120, 240, 277, and
480 are tested for acceptance, each test shall be performed at the lowest rated voltage and at the highest
rated voltage unless otherwise specified.
4.6.2.1.1 Failure of the metering device to perform all functions as specified in a test procedure or
performed safely, accurately and reliably.
4.6.2.2.1 The metering devices fail the certification tests as specified in Table 2 below:
n TESTED I O 1 2 3 or more
--`,`,````,,`,,,,,,`,,,,,```,`,-`-`,,`,,`,`,,`---
Examdes: The following examples explain how to apply Table 2. Also, reference to "the series tests" in
this paragraph means tests required to be performed in the series manner as specified in Section 4.1.6.,
and reference to "the parallel tests" means testing is not required to be performed in any particular
sequence (either series or parallel).
ExamPle I: If 3 metering devices are selected for the series testing and one failure occurs in any test
procedure, the meter type certification will be rejected and the entire seven series tests will be started
over from the beginning.
ExamDie 2: If 9 metering devices are selected for the series tests and the first, second, and third failures
occur separately in three different tests or test procedures, the meter type certification will be rejected.
These failures described here mean that a failure of the first metering device during one test procedure, a
failure of a second metering device during another test procedure, and a failure of a third metering device
during another test procedure different from the tests that the first two metering devices have failed
previously. Once such failures occur, the entire seven series tests will be started over from the
beginning.
However, if 3 metering devices are selected for a parallel test performed concurrently with the 9 metering
devices selected for the series tests, the rejection criteria for the 3 metering devices tested in a parallel
test shall not apply to the 9 metering devices tested in series, or vice versa. In addition, if a group of
metering devices tested in a parallel test(s) fails according to the rejection criteria, only the particular failed
test(s) needs to be repeated.
4.6.2.2.2 The failure of two or more metering devices during the same test or test procedure.
circuits effectively in parallel and the appropriate current circuit(s) energized effectively in series, unless
otherwise specified.
AI tests shall be made at 23OC f 5OC, rated voltage k 3%, rated frequency $: 1 Hz,test amperes f 3%, and
unity power factor I 2O, unless otherwise indicated in specific tests. The metering device shall be stabilized at
ambient temperature before performance tests are made.
--`,`,````,,`,,,,,,`,,,,,```,`,-`-`,,`,,`,`,,`---
-
Table 4 Starting load test
--`,`,````,,`,,,,,,`,,,,,```,`,-`-`,,`,,`,`,,`---
__.
Table 6 - Effect of variation of power factor for single-element meters
P _.I__
MAXIMUM
CONDITION
--`,`,````,,`,,,,,,`,,,,,```,`,-`-`,,`,,`,`,,`---
network, three-phase three-wire, three phase four-wire delta, and two-phase five-wire
Reference I
-
Table 8 Effect of variation of power factor
for two-element three-phase four-wire wye meters
CONDITION
-
Table 9 Effect of variation of power factor
for threeelement three-phase four-wire wye meters
--`,`,````,,`,,,,,,`,,,,,```,`,-`-`,,`,,`,`,,`---
CONDITION
REFERENCE
Condition ( 2 )
4.7.2.5.1 Test No. 5a: Effect of variation of voltage on the solid-state ancillary device
A solid-state ancillary device can be tested for accuracy of the ancillary device and its input pulse initiator,
using electromechanical watthour meter disk revolutions as the input source for Test 5a. For testing the
accuracy of the solid-state ancillary device only, an auxiliary input pulse source may be used, bypassing
the input pulse initiator. A minimum count of 1O00 for the measured quantity is required to establish the
test accuracy. The test must recognize the ambiguity o f f 1 least significant digit. This test shall be made
with the solid-state ancillary device and meter combination energized with rated voltage and rated
frequency, at an ambient temperature of 23°C ?: 5°C.
The accuracy of the measured quantities shall not differ from the input source by an amount exceeding
that specified in Table 1I .
I CONDITIONS
DEVIATION FROM
URCE MEASURED
QUANTITY
1 1O0 Reference
2 90 20.1 %
I 3 110 20.1% I
4.7.2.6 Test No. 6: Effect of variation of frequency
The effect of variation of frequency upon the registration of a metering device shall not exceed the
maximum deviation specified in Table 12.
--`,`,````,,`,,,,,,`,,,,,```,`,-`-`,,`,,`,`,,`---
CONDITION
CONDITION
Reference performance
Reference
Conditions (1) & (2)
Condition (1)
current circuit of the three-wire element, as compared with the performance when both current circuits of
the three-wire element are used, shall not exceed the maximum deviation specified in Table 14. These
tests shall be made on each element separately with no current flowing in the current circuits of the
remaining element(s) but with the voltage circuits of all elements energized effectively in parallel.
Reference
performance for
Conditions (1) & (2) Both Circuits 0.5 0.5
Condition (1) Circuit A only 1 1
Condition (2) Circuit B only 1 1
Reference
performance for
Conditions (3)& (4) Both Circuits 5 5
Condition (3) Circuit A only 10 10
Condition (4) Circuit B only 10 10
In a multi-element, polyphase metering device, the change in performance produced by using only one
current circuit of the three-wire element, as compared with the performance when both current circuits of
the three-wire element are used, shall not exceed the maximum deviation specified in Table 15. The
current circuits that are not common to both elements of a two-element, three-phase, four-wire wye
metering device shall be loaded with twice the test current specified. The current circuits of any three-wire
element shall be connected in series and treated as one circuit.
Table 15
MAXIMUM
DEVIATION IN
CONNECTIONS PERFORMANCE
CONDITION OF CUR iNT CLASS FROM
CURRENT 10 20 REFERENCE
CIRCUITS CURRE PERFORMANCE
Reference performance
for Conditions (5),
(6).ci),(81, etc.
Condition (5)
Condition (6)
Ail Circuits
Circuit A only
Circuit B only
0.25
0.25"
0.25"
0.25
0.25"
0.25"
1.5
1.5"
1.5N*
I 3
3N'
3N*
Reference
+.5
I
k1.5
Conditions (7). (8). etc. Circuits C, D, etc. 0.25N" 0.25" 1.5" 3N' 5N' k1.5
Reference Performance
I
for Conditions (9),
(IO), (111, (121, etc. All Circuits 2.5 2.5 15 30
Condition (9) Circuit A only 2.5 2.5 15 30
Condition (10) Circuit B only 2.5 2.5 15 30
Conditions (11),(12),etc. Circuits C, D,etc. 2.5
- 2.5 15 30
The temperature rise of any of the current-carrying parts of the watthour metering device, tested under
specified conditions, shall not exceed 55OC, except that a higher temperature rise is permissible when
suitable insulating materials are used in conformance with the general principles of temperature rating as
specified by ANSIAEEE Std 1.
All tests shall be performed in a room essentially free from drafts with the metering device cover in place. The
metering device shall be mounted in a conventional manner on a suitably rated meter mounting device. Not
less than 4 ft (8 ft jumper between terminals) of stranded, insulated, copper conductor shall be connected to
the line and load current terminals of the metering device or socket. For detachable (type " S ) metering
devices, the opening where the conductors enter and leave the socket and any other openings shall be
closed with suitable material to prevent drafts. The conductor size, test current, and, where applicable, the
socket rating and simulated metering device are specified in Table 16.
Wire sizes for 100.200, and 320 A are those specified in ANSIINFPA 70 for 60% temperature rating.
In the case of metering devices provided with terminal compartments (type "A"), the test shall be conducted
under the test conditions specified in 4.7.2.9 until the current-circuit temperatures have stabilized. The
temperature rise shall be considered the difference in degrees Celsius between the stabilized temperature
and ambient (room) temperature. For detachable metering devices (type T')Class 100, 200, and 320, the
test installation shall be standardized using a simulated meter as specified in figures 1, 2, and 3. The
simulated meter shall have the same cover and number of current jumper bars as current circuits in the
metering device to be tested. A temperature-rise test shall be conducted on the simulated meter by applying
the test current to all jumper bars in series until the temperature as indicated by the temperature detector has
stabilized. This temperature shall then be recorded and the simulated metering device replaced by the
metering device to be tested. When the temperatures of the metering device current circuits have stabilized,
the temperatures shall be measured and the empirical temperature-rise values of the meter device current
circuits shall be calculated as follows:
--`,`,````,,`,,,,,,`,,,,,```,`,-`-`,,`,,`,`,,`---
e,=Measured final temperature rise of current circuit of simulated meter jumper bar for the same current
phase
Before the meter is energized, the resistances of the metering device current circuits and the ambient
temperature shall be determined. The resistance measurements shall be made by a means capable of
determining the change in resistance to an accuracy of 10.5% or better. The metering device shall be
energized at the specified conditions for a minimum period of 2 hrs. At the end of the prescribed period, the
meter device shall be de-energized, and the time that this action was taken shall be noted. Resistance
readings shall be taken on each current circuit and recorded along with the time at which each measurement
--`,`,````,,`,,,,,,`,,,,,```,`,-`-`,,`,,`,`,,`---
was taken. The resistance and time readings shall be repeated until three sets of data have been obtained
for each current circuit. These readings shall be taken as quickly as practicable. In no case, however, should
the overall time between de-energization and the last resistance reading exceed 5 minutes.
The temperature rise of the current circuit corresponding to each resistance reading should be calculated by
the following formulas:
R
T=258 (--1)forcopper windings
r
R
T=251(--1 )for aluminum windings
r
where:
T = temperature rise in degrees Celsius
R = hot resistance
r = cold resistance
To determine the temperature rise at the time of de-energization, the temperature rise corresponding to the
resistance values for each current circuit shall be plotted against time. The graph shall be extrapolated to the
time of de-energization.
-
0246 02Sü DIA
2 PLACES
0137
O860
0811
n n
0.364 R MAX
0.700 MAX
0.154 R MAX
Section'a-A
NOTES: (1) Msterisl is 0.094 f 0.002 by 0.7# f 0.005 inch round edge
copper with elektro-tin plate o.m-o.Oo05 inch thick
(2) select dimension "A" and retainllig lugs or c o m p m holes to suit
meterbaBeplateused
(3) The temperature detectors Shan be so attached and Bhpu be of such
type that thclr prescnice willnot appredobbaffectthe teinperahire rjse of
the j u m p h
(4) Au dimensiohs are in incha
(5) MeMc a n a m Multipb inches by 25.4 to obtain mig9neters.
Round off to nearest 0.02 bup.
-
Figure 1 Dimensions for jumper bars of simulated meter temperature-rise
test for single-phase and polyphase meters (maximum rating 100 A)
--`,`,````,,`,,,,,,`,,,,,```,`,-`-`,,`,,`,`,,`---
--`,`,````,,`,,,,,,`,,,,,```,`,-`-`,,`,,`,`,,`---
0.700 M A X
om a MAX
Farmed A-A
N U E S (1) Materiai is 0.094 i 0.002 by 0.750 i 0.006 inch round edge
copper with electro-an pìate O.ooo2-0.ûûOõ inch thick
(2) select àimension "A" and retabhg lu@ or cotter pin holes to suit
meter basepiate used.
(3) The tempeiature detectors shali be 80 attached and shaiì be of such
type that their presence will not appmciabìy afîect the temperature rise of
the jmper bars.
(4) dimensions 8 f e hl hCheS
(5) M e M c c9nvers3a. Multipb. inches by 25.4 to obtain mülÙneîem.
Round offto nearest 0.02 mm.
Figure 2 - Dimensions for jumper bars of simulated meter temperature-rise test for
single-phase and polyphase meters (maximum rating 101 200 A rating) -
I
YV ,... .-I., II. .
1
- brn.1"
PERFORMANCE
y I
Reference performance
for conditions (1),(2), 10 20 100 200 320 Reference
and (7)
Reference performance
for conditions (3) and (5) 0.25 3 5 Reference
Reference performance
for conditions (4) and (6) 2.5 30 50 Reference
Condition (1)
One-half hour after
application of load 10 1O0 200 320 I 1.o
Condition (2)
1
One hour after
application of load 10 20 1O0 200 320 k1.5
Condition (3)
Immediately following
test for condition (2) 0.25 0.25 1.5
Condition (4)
Immediately following
test for condition (3) 2.5 2.5 15
--`,`,````,,`,,,,,,`,,,,,```,`,-`-`,,`,,`,`,,`---
Condition (5)
Two hours after test for
condition (4) with meter
at no load current during
the two-hour interval 0.25 0.25 1.5 3 5 t1.5
Condition (6)
Immediatelyfollowing
test for condition (5) 2.5 2.5 I 15 30 50 I1 .o
Condition (7)
Immediatelyfollowing
20 1 & 100 tl .o
-
Table 18 Effect of Tilt
Reference performance
(2),
for conditions (l),
(3),and (4) 0.25 0.25 1.5 3 5 Reference
Condition (1)
Top of meter tilted 4
degrees forward 0.25 0.25 1.5 3 5 +.oI
Condition (2)
Top of meter tilted 4
degrees backward 0.25 I 0.25 I 1.5 3 5 trl .o
Condition (3)
--`,`,````,,`,,,,,,`,,,,,```,`,-`-`,,`,,`,`,,`---
Top of meter tilted 4
degrees left 0.25 0.25 1.5 3 5 I 1.o
Condition (4)
Top of meter tilted 4
degrees right 0.25 0.25 1.5 3 5 k1 .o
Reference performance
for conditions (5),(6),
(71,and (8) 2.5 2.5 15 30 I 50 I Reference
Condition (5)
Top of meter tilted 4
degrees forward 2.5 2.5 15 k0.5
Condition ( 6 )
Top of meter tilted 4
degrees backward k0.5
Condition (7)
Top of meter tilted 4
degrees left 30 I I 50 k0.5
Condition ( 8 )
Top of meter tilted 4
degrees right 2.5 2.5 15 3 k0.5
Available nominal voltage and current can be used for the duration of this test except when the metering
device is undergoing the specified accuracy test.
e For test conditions (7) through (12) in Table 19, a current shall be applied to Element B. The currents in
Element A and Element B shall be equal in magnitude, and each shall be substantially in phase with the
voltage applied to the respective element. For these test conditions, both the voltage circuit and the
current circuit of Element B shall be connected as follows:
For a two-element three-phase four-wire wye metering device, the current circuit common to both
elements shall not be connected. The currents used shall be twice the values indicated in Table 19. The
circuits of any three-wire element shall be connected in series and shall be tested as one circuit.
The difference between the performance of the metering device under the test conditions specified and
the applicable reference performance shall not exceed the maximum deviation in Table 19.
--`,`,````,,`,,,,,,`,,,,,```,`,-`-`,,`,,`,`,,`---
Reference
e
--`,`,````,,`,,,,,,`,,,,,```,`,-`-`,,`,,`,`,,`---
For test conditions ( 5 ) through (8) in Table 20 current shall be applied to the current circuits of Element B
and Element C.
These currents shall be equal in magnitude with the current applied to Element A, and each shall be
substantially in phase with the voltage applied to the respective element. For these test conditions, both
the voltage and current circuits of Element B and, similarly, the voltage and current circuits of Element C
shall be connected as follows:
The difference between the performance of the metering device under the test conditions specified and
the applicable reference performance shall not exceed the maximum deviation in Table 20.
Reference
,
Condition (3) 1.5 1.5 9 18 30 I 1.o
--`,`,````,,`,,,,,,`,,,,,```,`,-`-`,,`,,`,`,,`---
Reference performance
for conditions (5) & (7) 0.5 0.5 3 6 10 Reference
4.7.3 -
Accuracy tests external influences performance verification
Time, program and register readings shall be stored in the metering device and/or register to be used as
reference for tests 4.7.3.1 through 4.7.3.24. After each test, proper operation of the metering device
and/or register shall be verified by time, program, and register reading check, and the metering device
shall show no damage and shall operate correctly in accordance with the requirement of the standard. Any
change in energy and power quantities shall be limited to flleast significant digit (LSD) displayed, except
for test with load current applied.
Low-voltage electronic circuits, operating at less than 40 V rms, and all output relay terminals, shall not be
subjected to this test.
1.2/50 ps- 8/20 ps Combination Wave. These waveforms shall be applied at angular injections of O", 90°,
and 270" of the fundamental voltage waveform. This test may be omitted for electromechanical meters
and registers.
These waveforms will be applied in both the transverse and common mode with the AC voltage and
current inputs to the metering device. Self-contained meters are to be tested with the links closed and the
load side of the current circuits open. Transformer rated meters are to be tested with the polarity side of
the current circuits connected to the line and the non-polarity side open circuited.
This test subjects the power input of the meter device to a 100 kHz Ring Wave with a Peak Voltage of
6 kV and Short-Circuit Peak Current of 0.5 kA.
-
4.7.3.3.2 1.2150 microsecond 8/20 microsecond combination wave
-
The standard 1.2/50 ps 8/20 ps combination wave applied to the metering device shall be for location
category 83 and system exposure high, as described in ANSVIEEE C62.41, Table 3.
This test subjects the AC power input of the metering device to a 1.2/50 ps - 8/20 ps combination wave
with a peak voltage of 6 kV and peak current of 3 kA.
O - Condition (3). Vertically at the same distance in front of the test board as the center of the metering
device. The middle of the conductor shall be on the same level with the center of the metering device
and 10 inches to the right or left. The loop shall be in a vertical plane parallel to the test board.
For conditions (1) through (3),the change produced in the performance of a metering device by
application of a 1O0 ampere-turn external magnetic field shall not exceed the maximum deviation specified
in Table 21.
t
I-
I
I
CONDITION
Reference
performance
for conditions
(11, (2), and (3)
Condition (1)
Condition (2)
Condition (3)
0.25
I
CURRENT CLASS
20
0.25
I 100
CURRENT IN AMPERES
1.5
I 200
3
I 320
5
POSITION OF
CONDUCTOR
MAXIMUM DEVIATION IN
PERCENT FROM
REFERENCE
PERFORMANCE
Reference
The test shall be applied to three metering devices. The metering devices shall be placed in a space
having a temperature of 23°C I5"C and allowed to stand for not less than 2 hours with the voltage circuits
of the metering devices energized. Reference performance at each of the loads specified in Table 22 shall
be obtained after operating the metering devices for 1 hour at the specified load. The metering devices
shall then be operated and tested at each of the following conditions:
- Conditions (1) through (6). These tests shall be made with the metering device placed in a space
having a temperature of 50°C f 5°C. After energizing the voltage circuits of the metering devices for a
period of not less than 2 hours, the appropriate test currents at the power factors listed for conditions
(1) through ( 6 ) of Table 22 shall be sequentially applied to the metering devices. Each condition shall
be maintained for a period of at least 1 hour before tests are made to determine the deviation from
reference performance.
--`,`,````,,`,,,,,,`,,,,,```,`,-`-`,,`,,`,`,,`---
Available nominal voltage and current can be used for the duration of this test except when the
metering device is undergoing the specified accuracy test.
- Conditions (7) through (12). Repeat conditions (1) through (6), respectively, except that metering
devices shall be placed in a space having a temperature of -20°C +5"C. The effect of variation of
temperature upon the performance of the metering devices shall not exceed the maximum deviation
specified in Table 22. Available nominal voltage and current can be used for the duration of this test
except when the metering device is undergoing the specified accuracy test.
DEVIATION IN %
FROM
CURRENT CLASS REFERENCE
CONDITION 10 POWER AMBIENT PERFORMANCE
FACTOR TEMPERATURE AT NOMINAL
NRRENT IN AMPERES TEMPERATURE
DIFFERENCE'
Reference i i
performance for o'2 3 5 1.o 23OCk5OC Reference
0.25 1.5
conditions (1) 5
and (7)
Reference
performance for 2.5 2.5 15 30 50 1.o 23OCk5OC Reference
conditions (2)
and 18)
Reference
performance for 10 50 100 150 1.o 23oci5oc Reference
5
conditions (3)
--`,`,````,,`,,,,,,`,,,,,```,`,-`-`,,`,,`,`,,`---
1 1 1 1 1 1
2.5
5
0.5
2.5
5
0.25
2.5
5
0.5
2.5
5
I 1 1 1 1 1
-20°C150C 11 k3.0
'When the actual temperature difference between two tests differs from the nominal temperature difference specified for the two
tests, the deviation shall be adjusted proportionally.
e
Page 39
A solid-state ancillary device can be tested for accuracy of the ancillary device and its input pulse initiator,
using electromechanical watthour meter disk revolutions as the input source for Test 19a. For testing the
accuracy of the solid-state ancillary device only, an auxiliary input pulse source may be used, bypassing
the input pulse initiator. A minimum count of 1000 for the measured quantity is required to establish the
test accuracy. The test must recognize the ambiguity of tl least significant digit.
This test shall be made with the solid-state ancillary device and meter combination energized with rated
voltage and rated frequency. The ancillary device, while energized, shall be exposed to each specific test
temperature for at least two hours prior to the test. The accuracy of the measured quantities shall not differ
from the input source by an amount exceeding that specified in Table 23.
--`,`,````,,`,,,,,,`,,,,,```,`,-`-`,,`,,`,`,,`---
effects, condition (1) shall be conducted before tests of condition (2).
4.7.3.10 Test No. 24: Effect of variation of ambient temperature-secondary time base
This test shall be conducted with the metering device in the battery carryover mode. The accuracy of the
secondary time shall be within +0.02% (2minutes per week) at ambient temperatures of -30°C I5"C and
70°C t5"C. The metering device shall be exposed to each specified temperature for not less than 2 hours
prior to testing.
The test shall be conducted utilizing the test equipment configurations provided in Figures 4 and 5. The
test shall be carried out according to IEC 61O00 PT 4, under the following conditions:
This test shall be conducted on all metering devices containing solid-state components excluding LED
voltage indicators. This test may be omitted for electromechanical meters and registers.
0.1 M E T E R M I N . ( A L L G R O U N D P L A N E E D G E S )
SURGED LINE
30 CENTIMETERS
NO N - C O N D U C T IV E S U P P O R T
HIGH- F R E Q . G R O U N D S U C H
AS 1 BRANDED STRAP
POWER RETURN
1 METER MAX. 0.1 M E T E R
1 - E Q U I P M E N T O N G R O U N D P L A N E M U S T B E 0.5 M E T E R
FROM OTHER CONDUCTIVE STRUCTURES.
2 - L E A D S M U S T BE K E P T A M I N I M U M O F 0.1 M E T E R A B O V E
GROUND PLANE
3 - G R O U N D P C A N Ë ' M U S T B E A MINIMUM O F 1.0 M E T E R x
1.0 M E T E R W I T H A T L E A S T 0 . 1 M E T E R O F G R O U N D
PLANE EXTENDING B E Y O N D A L L E Q U I P M E N T O N THE
GROUND PLANE.
GROONDREFERENCEPLANE 1
--`,`,````,,`,,,,,,`,,,,,```,`,-`-`,,`,,`,`,,`---
provided in Figures 6, 7, 8, and 9. These figures shall be followed as closely as possible, appropriate to
type of meter tested and test chamber utilized for the test.
This test shall be conducted on all metering devices containing solid-state components excluding LED
voltage indicators.
The test sample shall be subjected to both vertical and horizontal polarized continuous wave signals over
a frequency range of 200 kHz-10 GHz with a field strength of 15 +/-5 V/m. The test shall be performed
with the antenna facing the most sensitive side of the meter. The field may be generated by 1) a linearly
polarized antenna positioned vertically and again with the antenna positioned horizontally; 2) a circularly
polarized antenna may be used to simultaneously provide both vertical and horizontal susceptibility testing
over those frequency ranges where circular polarized antennas are available; or 3) a uniform field
generator. The test procedures shall be conducted with samples configured so that disturbances can be
readily noted. Optional (add-on) functions and circuitry shall be installed when this represents a normal
configuration for the test sample. Special internal wiring or wire routing of the test sample are prohibited.
The test fixture shall be composed of a minimum amount of metal (or other EM1 reflecting or absorbing
material) capable of shielding or otherwise distorting the field in the vicinity of the test sample. If a uniform
field strength is not available, the fixture must allow the test sample to be oriented in each of 1O
orientations to allow both horizontal and vertical irradiation of the front, left side, right side, top, and bottom
of the test sample.
Below 1 GHz, the signal must be 90% amplitude modulated with a 1.O kHz sine wave. A continuous wave
signal is used above 1 GHz. Beginning at 200 kHz, the scan rate will double the frequency no faster than
--`,`,````,,`,,,,,,`,,,,,```,`,-`-`,,`,,`,`,,`---
every 200 seconds (.O05octaveslsecond) through 10 GHz.
One test sample is used to determine the orientation which provides the greatest sensitivity.
With a field strength set to 15 +/- 5 Vlm, test the test samples over a frequency range in the most sensitive
orientation.
In each orientation above, the fixture must place the test sample in a test volume in which the field
strength remains within acceptable test limits.
When using GTEM testing, power and I/O leads should be only as long as needed to make connection
from the GTEM shielded I/O connectors to the test sample. Leads shall not exceed 5 meters in length.
Excess leads shall be coiled in a 0.4 meter diameter coil and supported 0.02 to 0.1 meter off the floor and
other metal surfaces of the GTEM.
4.7.3.13 Test No. 27: Radio frequency conducted and radiated emission test
The metering device shall conform to all applicable requirements of the Code of Federal Regulations
(CFR) 47, Part 1&Radio Frequency Devices, Subparts A-General and &.Unintentional Radiators
issued by the Federal Communications Commission for Class "B" digital devices. (Refer to ANSI C63.4).
The test shall be conducted with all cables connected, with all options and accessories specified, in a
configuration closely resembling typical field in-service connections. Typical inservice configurations are
provided in Figures 6, 7, 8, and 9. These figures shall be followed as closely as possible, appropriate to
type of meter tested and test chamber utilized for the test.
This test shall be conducted on all metering devices containing solid-state components excluding voltage
indicators. This test may be omitted for electromechanical meters and registers.
I I
1
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RF I
n
n lo1
n
'.' "IEW .'Ì
I I
I
U U
Figure 6 -Typical test layout for radiated susceptibility-Test 26 and radiated and conducted
emissions-Test 27. Reference 4.7.3.12.1 and 4.7.3.13
,-
LINE CONDUCTORS
{,lNDMDUAL CONDUCTORS
14 AWG WE T ” N OR EûUIVALENT
s M ~ R INS ENGRI
UNSHIELDED AND NOT TWISTED
I
EACH END TO BE
INSULATED
L 4 INDMDUAL CONDUCTORS
5.
14 AWG WE M H N DR EOUNALENT
O METE‘RS IN LENGTH
UNSHIüDED AND NOT lWISED * UNE INPEDWCE STABIUZATIDN
NETWORK
LOAD CONDUCTORS
Figure 7 - Typical wiring detail for self contained meters for radiated susceptibility-Test 26 and
radiated and conducted emissions -Test 27. Reference 4.7.3.12.1 and 4.7.3.13
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I 1
A 1
INDMDUAL CONDUCTORS
14 AWG, NPE T " N OR EQUIVALENT --
&
.O METERS IN LENGTH
UNSHIELDED AND NOT MlSTED * UNE INPEDENCE STABIUZATIDN
CURRENT CIRCUIT LOAD CONDUCTORS NEIWORK
Figure 8 -Typical wiring detail for transformer rated meters for radiated
susceptibility -Test 26 and radiated and conducted emissions -Test 27.
Reference 4.7.3.12.1 and 4.7.3.13
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Figure 9 - Typical GTEM test layout for radiated susceptibility Test.- Reference 4.7.3.12.1
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NOTES -
1 Uniformity of the test field must be demonstrated to ensure field does not fall below minimum field
requirements.
2 Ail power and cabling exiting the enclosure must be suitably filtered to prevent RF leakage.
3 Orientation of the test meter is shown for front, horizontal polarization.
4 Field intensity is controlled by septum voltage (direct measurement), or by field probes located in the cell.
5 Field strength should be determined from the central axis of the meter : voltage on septum divided by
septum height equals field strength.
Discharges shall be applied only to such points and surfaces of the metering device that are normally
accessible with the cover on. Discharges shall not be applied to any point that is accessible only for
maintenance purposes.
This test shall be conducted on all metering devices containing solid-state components excluding voltage
indicators.
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4.7.3.15 Test No. 29: Effect of storage temperature
The metering device shall not be damaged and shall conform to the manufacturer's specification after
being subjected to the following tests. The storage temperatures are as specified by the manufacturer. If
the operating temperature range is the same as the storage temperature range, then this test can be
omitted.
The metering device enclosure door or cover shall be closed (normal operating position) for the
duration of the test.
The metering device shall not be powered nor operating for the duration of the test.
The test duration shall be 168 hours.
The temperature shall be cycled once each 24 hours, as described below. The temperature
ramping shall be smooth and continuous. The rate of temperature change during ramping shall
not exceed 20°C,per hour.
The daily temperature cycle shall be conducted as follows:
- Ramp up from room ambient to the Maximum Storage Temperature, Tstor-Marin approximately
3 hours.
- Soak at TStor-Maxfor approximately 11 hours.
- in approximately 6 hours.
Ramp down to Minimum Storage Temperature, TstoreMin
- Soak, ,at
, , ,T for approximately 3 hours
- Ramp up to room ambient, in approximately 2 hours
- The metering device enclosure door or cover shall be closed (normal operating position) for the
duration of the test.
- The metering device shall be powered and operating in a normal manner for the duration of the
test.
- The temperature shall be cycled once each 24 hours, as described below. The temperature
ramping shall be smooth and continuous. The rate of temperature change during ramping shall
not exceed 2OoC, per hour.
- in approximately 6 hours.
Ramp down to minimum operating temperature, Toperain
- Soak at Toperain
for approximately 3 hours
- Ramp up to room ambient, in approximately 2 hours
- If present, the battery carry-over function shall be tested by removing the external power for
any 48 hour period during the temperature test.
Available nominal voltage and current can be used for the duration of this test when run independent of
any other test.
- The metering device enclosure door or cover shall be closed (normal operating position) for the
duration of the test.
- The metering device shall be powered and operating in a normal manner for the duration of the
test.
- The test duration shall be 24 hours at 85°C and 95% &4% relative humidity or 72 hours at 40°C
and 95% +4% relative humidity.
- The temperature shall be cycled once at 85°C and 95% +4% relative humidity or three times at
40°C and 95% +4% relative humidity, as described below. The temperature ramping shall be
smooth and continuous. The rate of temperature change during ramping shall not exceed 2OoC,
per hour. The relative humidity shall be held at 95% +4% during the peak temperature soak --`,`,````,,`,,,,,,`,,,,,```,`,-`-`,,`,,`,`,,`---
period.
- There shall be no condensation on the components and assemblies of the metering device.
Relative humidity need not be controlled during ramping, except to prevent condensation.
Available nominal voltage and current can be used for the duration of this test when run independent of
any other test.
- The metering device shall not be operating and shall be without packaging
- The metering device shall be rigidly mounted to a test fixture and the reference point for the
control accelerometer shall be attached to the test fixture.
- Half sine pulse applied 3 times in each direction, for each of the 3 mutually perpendicular axis, for
a total of 18 shocks.
This test shall be conducted as described as Shock Testing in the International Safe Transit Association
Test Procedure 3 A, Performance Test for IndividualPackaged-Products Weighing 750 Ib. (68 kg) of Less.
(revision date: July 2000).
- The metering device shall not be operating and shall be without packaging
- The metering device shall be rigidly mounted to a test fixture and the reference point for the
control accelerometer shall be attached to the test fixture.
- The test shall be run over a frequency range of 30 to 350 Hz, with a sweep time of one octave per
minute at 5 m/s2(0.5 g) along each of three mutually perpendicular axes.
The metering device, packaged in its intended packing container shall pass the requirements described as
Vibration Testing in the International Safe Transit Association Test Procedure IA, Performance Test for
IndividualPackaged-Products Weighing 750 Ib. (68 kg) or Less. (revision date: July 2000). This test must
be done on the same metering devices and the same packaging as test number 33, and must be done
before test number 33.
This test exposes the metering device, packaged for shipment, to transportation, for approximately one
hour.
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- Each 2-hour cycle shall consist of 102 minutes of light exposure followed by 18 minutes of both light
and water spray.
- The light source shall be a xenon-arc lamp utilizing borosilicate glass inner and outer optical filters to
simulate the spectral power distribution of natural daylight. The irradiance measured at 340 nm shall
be maintained at 0.35 W/m2throughout the test. During the light-only portion of the cycle, the black
panel temperature shall be maintained at 63°C.
- The water spray shall be applied to the metering devices under test using spray nozzles adjusted so
that water is sprayed onto the surfaces of the test samples that are normally exposed to the weather.
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After this test, covers, terminal covers, etc. shall be readily removable. There shall be no progressive
corrosion or electrolytic action that will adversely affect the functioning of any part of the meter. Also,
there shall be no evidence of deleterious discoloration or fading of finishes or materials.
After this test, covers, terminal covers, etc., shall be readily removable. There shall be no progressive
corrosion or electrolytic action that will adversely affect the functioning of any part of the apparatus.
New metering devices shall be either 100% tested by the utility, sample tested by the utility, or 100%
tested by the manufacturer.
Watthour meters placed into service or returned to service shall meet the provisions as set forth in this
Section.
All watthour meters and their associated equipment shall be thoroughly inspected at the time of installation
to assure safe and accurate operation.
5.1.3 Tests
5.1.3.1 As-found tests
As-found tests are done to determine the watthour meter accuracy before recalibration.
5.1.4 Performancetests
5.1.4.1 General
The performance of watthour meters should be verified by an annual test program such as one of the
three plans listed below. Records shall be maintained on each watthour meter tested. Subsequently, an
analysis of the test results for each group of watthour meters shall be made and appropriate action shall
be taken. The generally accepted plans for testings are:
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5.1.4.2 Objectives
The primary purpose of performance testing is to provide information on which the utility may base a
program to maintain meters in an acceptable degree of accuracy throughout their service life.
The variable-interval plan provides for the division of watthour meters into homogeneous groups. The
establishment of a testing rate for each group is based on the results of performance tests made on
watthour meters longest in service without test.
The statistical sampling plan provides for the division of watthour meters into homogeneous groups. The
annual selection process is random where each watthour meter within each group has an equal chance of
being selected.
The minimum number of meters to be tested in each group shall be 200 meters or 12.5% of that group,
whichever is less.
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NOTE-Examples of statistical sampling plans can be found in ANSVASQC Z1.9, the ANSI version of MIL-STD-414and
ANSVASQC Z1.4, the ANSI version of MIL-STD-105.
a) the number of meters in each group at the beginning of the test year
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watthour meter is not a simple matter, since it involves the characteristics of the meter and the loading.
Various methods are used to determine a single figure that represents the average percentage
registration, the method being prescribed by commissions in many cases. Four methods, described in
5.1 5.1-5.1.5.4 are used for determining the average percentage registration (commonly called "average
accuracy" or "final average accuracy").
5.1.5.1 Method I
Average percentage registration is the weighted average of the percentage registration at light load (LL)
and at full load (FL), giving the full load registration a weight of four. By this method
5.1.5.3 Method 3
Average percentage registration is the registration at a single point when this single point represents the
registrationwithin the load range.
5.1.5.4 Method 4
Average percentage registration for Polyphase meters is the weighted average of the percentage
registration at light load (LL), Full Load (FL), and Power Factor (PF), giving the full load registration A
weight of four, and the light load registration A weight of two. By this method.
mod
Average percent registration = 4FL + 2 LL + PF
7
Under usual operating conditions, the performance of a pulse recording device shall be acceptable when
the kilowatthours calculated from the pulse count do not differ by more than 2% from the corresponding
kilowatthour meter registration. The device's timing error shall be no more than &2 minutes per week.
5.3.3.2 inspection
When metering installations are inspected the instrument transformers associated with the installations
should receive a close visual inspectionfor correctness of connections and evidence of any damage.
All tests shall be made at 23°C f 5"C, rated voltage I3%, rated frequency I 1 Hz, test current 13%, and
unity power factor e%, unless otherwise indicated in specific tests. The metering device should be
stabilized at ambient temperature before performance tests are made.
After each test, a sufficient time interval shall be allowed for the pulse device to come to a stable condition
before making the next observation or test. <
6.3.4 Insulation
With the meter device voltage and current circuits de-energized, the insulation between current carrying
parts of separate circuits and between current-carrying parts and other metallic parts shall be capable of
withstanding the application of a sinusoidal voltage of 2.5 kV rms, 60 Hz for 1 minute. The input circuit of
the pulse initiators with independent power supplies power supply shall be tested at 1.5 kV rms, 60 Hz for
one minute. The leakage current shall not exceed 0.005 A per circuit. For both the I.5 and 2.5 kV rms test,
low-voltage electronic circuits, operating at less than 40 V rms, and all output relay terminals, shall not be
subjected to this test.
The pulse device shall operate at each test condition for at least 1 hour. An acceptable pulse device shall
not gain but may lose one pulse when all pulse circuits are energized under any of the test conditions in
Table 27 at 85%, loo%, and 110% of nameplate voltage.
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Vector # 710, or equivalent, incandescent light source to simulate sunlight. The incandescent light
shall be 600 watt and 3,200" K blackbody radiation as a minimum.
e) The metering device shall be exposed to the incandescent light source for a minimum of five minutes
at each position described below.
9 The incandescent light source shall be pointed directly toward the metering device and positioned at a
maximum direct distance of 19 inches from the center of the face of the meter cover as shown in
Figures 1O and 11. Tests shall be conducted at each of the following positions:
1. Twelve positions around the meter base.
2. Eight positions at a 45' angle from the meter base.
3. One position at a perpendicular to the face of the meter.
g) Verify metering device operations and report the direct and remote meter readings before and after
each Sunlight Interference Test
h) An acceptable pulse device shall agree within one pulse from the number of pulses expected, at each
position, after a minimum of 1O0 revolutions of the watthour meter. A pulse difference of two pulses at
any one position is a failure.
‘i!
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-
Figure 10 Sunlight interference Test
O"/
/ /
I 457
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APPENDIX A
(Informative)
Measurement of Power, Energy, and Related Quantities
connected one in each of the outside wires and the voltage leads of each wattmeter connected between its
current coil wire, preferably on the receiving circuit side, and the third, common or neutral wire.
e
A.l.4.2 Single-phase three-wire circuits
The total power in a single-phase three-wire circuit may be measured by two Wattmeters connected as in
A.1.3.2.
a
-
A.1.6 Three-phase circuits
A.1.6.1 Three-wattmeter method
If the three loads are accessible as single-phase two-wire loads, the total power may be measured as the
sum of the readings of the three wattmeters, each connected to one of the three loads as described in
A.1.4.1. This method is correct for all conditions of loading. This method is also correct for three-phase four-
wire circuits, except that the voltage coil of each wattmeter is connected between the line conductor in which
its current coil is connected and the common conductor, or the neutral.
e In general, electric energy is measured in the same way as electric power, by substituting an integrating
watthour meter for a wattmeter.
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There are two basic designs of a single-stator meter, called a network meter, that may be used for this
purpose. Both designs utilize one voltage coil and two current coils. Depending on whether the voltage coil is
energized from the line-to-neutral or the line-to-line voltage, one or two phase-shiftingnetworks are employed
to shift the phase of the current in one or both of the current coils in the proper amount and in the right
direction to enable them magnetically to react correctly with the line-to-neutral or line-to-line voltage,
respectively.
In the design utilizing a voltage coil energized by line-to-line voltage, the number of voltage-coil turns is
reduced from that of a 240 V coil to compensate for the reduction in voltage from 240 V to 208 V. Either
meter will register correctly on loads of any connection or power factor as long as the voltages are balanced,
symmetrical, and in the correct phase sequence. Since a particular phase sequence is essential to the
correct registration of this meter, a visual phase-sequence indicator is a built-in feature.
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A.2.4 Two-phase circuits
A.2.4.1 Two-phase three-wire circuits
The energy in a two-phase, three-wire circuit may be metered by means of two watthour meters connected in
the same way as the two wattmeters described in A.1.5.1.
The two current coils of equal rating are connected one in each of the conductors that have the neutral
between them and their associated voltage coils connected between these phase conductors and the
neutral. The one-half-rated current coil is connected in the remaining phase conductor and its double-rated
voltage coil is connected between that phase conductor and the neutral. This method is accurate for all
conditions of loading and power factor with or without voltage balance.
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A.2.9.1 Three single-phase three-wire stators
The energy in a three-phase, seven-wire double wye-connected circuit may be measured by means of three
single-phase, three-wire watthour meters, or their polyphase equivalent. This method is correct for all values
of balanced or unbalanced current and power factor, provided that the voltages are symmetrical and
balanced within acceptable limits.
Since, however, this maximum current is not a suitable value to use when calibrating or testing a meter, the
manufacturer designates the recommended value of amperes, called the 'test amperes,' to be used when
calibrating the meter. For example, a Class 100 meter might have a test-ampere designation of 15 A,
abbreviated as 'TA 15,' and a Class 200 meter might have a TA 30 nameplate rating. Because modern
meters are frequently required to perform with acceptable accuracies at values of current, voltage, and
frequency, that may differ appreciably from those used to calibrate the meter, compensating devices have
been developed to maintain, within acceptable limits, the calibration accuracy at the calibrating points and
over wide variations therefrom. Moreover, such devices are used to compensate for environmental
conditions, such as changes in ambient temperature, and for other conditions that are not always ideal. No
compensating device is perfect, but all in current use perform well within acceptable limits.
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this calibration is made with a lagging power factor and the meter is then operated at a leading power factor,
a slight difference in its accuracy, usually negligible, may result.
A.2.11 .a Surges
Meters installed in rural areas are more exposed to the elements than those in the more congested urban
areas. As a result, atmospheric electrical disturbances have a greater opportunity to affect adversely the
proper functioning of such meters. These disturbances are capable of producing, under certain
circumstances, very large currents of short duration, called surge currents. These currents may go to ground
through or in the vicinity of the meter. When this happens, the excessively large magnetic field created may
affect the strength of the permanent magnets in the meter, thereby resulting in registration errors.
In addition to surge proofing of the permanent magnets, a modern meter has built-in surge proofing for its
insulation. For both voltage and current coils, built-in protective gaps to ground are used. In addition, the
voltage coil has increased surge resistance across the coil.
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The quantity thus defined is not, in general, equal to the average value of the power factor during the interval,
but may be referred to as the interval power factor.
(Q - hours)-(watthours x cos60")
var hours =
sin 60"
electromechanical meters. Multiple registers are usually provided to measure reactive energy flow in both
directions. The phase angle of the current with respect to the voltage is expressed in terms of leading or
lagging power factor.
6.1 General
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The purpose and scope of this section is to specify the standards of electrical measurement and of time
interval to which the metering of electric energy shall be referred, and to outline an appropriate chain of
intermediate steps between the national standards of measurement and the watthour meters used in the
meter shop.
B.2.1.1 “The unit of electrical resistance shall be the ohm, which is equal to one thousand million units of
resistance in the centimeter-gram-secondsystem of electromagnetic units.”
8.2.1.2 “The unit of electric current shall be the ampere, which is one-tenth of the unit of current in the
centimeter-gram-second system of electromagnetic units.”
B.2.1.3 “The unit of electromotive force (em9 and of electric potential shall be the volt, which is the
electromotive force that, steadily applied to a conductor whose resistance is one ohm, will produce a current
of one ampere.”
B.2.1.4 “The unit of electric quantity shall be the coulomb, which is the quantity of electricity transferred by a
current of one ampere in one second.”
B.2.1.5 “The unit of electrical capacitance shall be the farad, which is the capacitance of a capacitor which is
charged to a potential of one volt by one coulomb of electricity.”
8.2.1.6 ”The unit of electrical inductance shall be the henry, which is the inductance in a circuit such that an
electromotive force of one volt is induced in the circuit by variation of an inducing current at the rate of one
ampere per second.”
B.2.1.7 “The unit of power shall be the watt, which is equal to ten million units of power in the centimeter-
gram-second system, and which is the power required to cause an unvarying current of one ampere to flow
between points differing in potential by one volt.”
8.2.1.8 “The units of energy shall be (a) the joule, which is equivalent to the energy supplied by a power of
one watt operating for one second, and (b) the kilowatthour, which is equivalent to the energy supplied by a
power of one thousand watts operating for one hour.”
8.2.1.9 The unit of time interval is the atomic second, defined in 1967 by international agreement as a
certain number of periods of a specified atomic transition of cesium 133.
’ Guidelines for implementing the New Representationsof the Volt and Ohm Effective January 1, 1990,
NISTTechnical Note 1263, June 1989.
Transport .................................................................................................................................................................................
Standard
FieldMlorking/Portable Standard 1
i Customers Meter
-
Figure 9.1 Traceability path diagram
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It may be equipped and staffed to make calibration tests at some or all of the sequential steps intermediate
between the national standards of resistance, emf, and time interval, and a local reference standard of
energy measurement (such as a group of watthour meters).
disturbances, electrical and magnetic interference, and noise, be held to such levels that normal
measurement techniques and results are not adversely affected.
The ambient relative humidity should be kept to values low enough that electrical insulation in the equipment
used will not be affected. Relative humidities below 55% should be adequate for this purpose. In the absence
of adequate shielding and guarding of laboratory instruments and circuits, the effects of bound electrostatic
charges may be troublesome at very low humidities. However, shielding may well be a simpler and better
solution to this problem than an attempt to hold humidity above some specified minimum value, say 40%.
O avoid excessive humidity in the event of the failure of the control element.
Rectified direct-current supplies should be substantially free from ripple, since the presence of ripple and its
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waveform have different effects on instruments having peak, average, or rms response.
Alternating-current supplies should be substantially free from waveform distortion, and the phase relation of
combined current and voltage supplies should be capable of close regulation, since these factors may also
influence calibration and measurement accuracy. For the most accurate watthour meter calibrations, the third
harmonic in the current wave should not exceed 0.5% of the fundamental, and other harmonics in the current
and voltage waves should not exceed 1.O%.
The use of reference standards should be limited to assigning and checking the values of secondary
standards. Reference standards should not be exposed to the hazards of accidental misuse that occasionally
occur in routine measurements. Further advantages may accrue if the basic reference standards of a
laboratory never leave it; that is, are never subjected to transportation hazards. In this case, special transport
standards must be available for the periodic interlaboratory comparison tests that act as a check on the
stability of the basic reference standards.
8.6.2.1 Intercomparison
Ideally, the basic reference standards of a laboratory should be maintained in groups of three or more
separate individual units that can be intercompared readily, since three is the minimum number of units for
which a change in one of them can be both detected and located by intercomparison.
e In some cases, specially calibrated transport standards are used in a Measurement Assurance Program
(MAP) to aid in the achievement of measurement quality control and to link the measurements in the
laboratory to national standards.
Additional standards having the following intermediate values of 0.002, 0.005, 0.02, 0.05, 0.2, 0.5, 2, 5, and
20 R are convenient since they permit the calibration of most values of current shunts by direct substitution
techniques without the precise calibration of bridge ratio arms. Alternatively, a precise 2:l ratio can be
established from the combinations of three nominally equal standards.
- Its components must be guarded or otherwise be adequate to eliminate errors from leakage
currents across insulating members.
- It must be designed to avoid or minimize changes in ratio resulting from self-heating at rated
voltage or from ambient temperature changes.
B.6.8.1 Stability
The transfer characteristics of an acdc transfer standard (that is, its acdc differences) are functions of its
geometry, its electrical parameters, and its operating level, and should not change significantly with time.
Hence, the transfer characteristics of an instrument need be determined infrequently, unless the components
of its measuring circuit are modified or replaced, or their physical arrangement altered. However, the dc
calibration of a transfer instrument should be verified periodically.
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energy standard is maintained in many laboratories as an essential part of their reference equipment,
frequently in conjunction with instrument transformers having appropriate ratios, such that the reference
standard watthour meter can always be operated at the same current and voltage level, regardless of the
current or voltage requirements of the meters compared with the reference meters. Usually such standards
are housed in a temperature-controlled environment and are continuously energized.
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Classes 0.25 or 0.5 (or in some instances even 1.O) may be appropriate. The corrections to shop instruments
should be regularly and frequently redetermined, using laboratory secondary-standard instruments.
B.12.1.3 Tolerances
The standard meter under test shall be considered to be within the specified limit unless the test result
exceeds the limit by more than the value of the measurement uncertainty assigned to cover the possible
errors in the laboratory reference standards, observations, and procedures.
All parts that are subject to corrosive influence under normal working conditions shall be effectively protected
against corrosion due to atmospheric causes. Any protective coating shall not be liable to damage by
ordinary handling or injuriously affected by exposure to air under ordinary conditions. The construction of the
meter shall be suitable for its purpose in all respects, and shall give assurance of permanence in all
mechanical, electrical, and magnetic adjustments.
8.12.2.4 Case
The case shall be of sufficient strength to afford to the working parts adequate protection against damage
under normal conditions of handling, usage, and transport; and it shall afford to the interior substantial
protection against the entry of dust. Portable standard meters should be fitted with a detachable cover to
enclose the readout, terminals, and controls, and be equipped with a substantial carrying strap. The inside of
the cover should include a means for attaching a calibration card.
B.12.2.5 Sealing
Provision shall be made for the sealing of the standard meter to detect unauthorized access to working parts
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and to electrical and magnetic adjusting devices.
8.12.2.6 Window
A window of glass or other suitable transparent material shall be provided to permit a clear view of the
readout. It shall be substantially dusttight and shall be replaceable.
B.12.2.7 Terminals
Terminal identification shall be adjacent to each terminal and shall be of a permanent nature.
B.12.2.11 Nameplate
A nameplate shall be provided on the outside of the case to show all necessary information, including
manufacturer, type, serial number, voltage ratings, current ratings, frequency, model number, and watthour
constant (KJ or energy constant (y) at basic voltage and current ratings.
readily detectable. Facilities for adjusting the level of the standard meter shall be provided.
B.12.3.4 Case
The case shall be of sufficient strength to afford to the working parts adequate protection against damage
under normal conditions of handling, usage, and transport; and it shall afford to the interior substantial
protection against the entry of dust.
8.12.3.5 Sealing
Provision shall be made for the sealing of the standard meter to detect unauthorized access to working parts
and to electrical and magnetic devices.
8.12.3.6 Window
A window of glass or other suitable transparent material may be provided, if applicable, to permit a clear view
of the readout. It shall be substantially dusttight and shall be replaceable.
O B.12.3.7 Terminals
Terminal identification shall be adjacent to each terminal and shall be of a permanent nature.
B.13.1.4 Frequency
The frequency shall be 60 Hz and be constant to within f0.2%.
8.13.1.7 Level
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Standard watthour meters of the induction type shall be level to within I0.5".
B.13.1.9 Insulation
The insulation between current-carrying parts of separate circuits and between current-carrying parts and
other metallic parts shall conform to ANSVISA S82.01, Section 9.12, and shall be capable of withstanding the
application of a sinusoidal voltage of 2.3 kV rms, 60 Hz, for 1 minute.
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B.13.2 Performance requirementsfor portable standard meters
8.13.2.1 Drift
Test Condition (1): With 250% rated current and with the voltage circuit open, the indication must not change
perceptibly in 1 min.
Test Condition (2): With 100% rated current, the braking device on standard watthour meters of the induction
type shall immediately release the rotor when 70% rated voltage is applied.
Test Condition (2): With 100% of rated current, at 1.0 and 0.5 power factors, the registration at 90% and
110% of rated voltage shall not differ from the value at 100% of rated voltage by more than the amount
specified in Table 28.
NOTE-When a meter is furnished with an extemal multiplier for the purpose of extending the voltage range, this test shall include the
extended voltage rating with the multiplier connected in the circuit.
Test Condition (1): The portable standard meter shall be placed in a space having a temperature of 0°C
+5"C for not less than 2 hours with the voltage circuit energized. The meter shall be tested with 100% of
rated current at 1.O and 0.5 power factors.
Test Condition (2): Repeat condition (I), except that the portable standard meter shall be placed in a
space having a temperature of 50°C -15°C. At 0°C +5"C and 50°C I5"C the registration shall not differ
from the value at 23°C X2"C by more than the amount specified in Table 28.
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1 TEST CONDITIONS i
% MAXIMUM
TEST %V %I PF OTHER DEVIATION
Reference Conditions 1O0 1O0 1.o
8.13.1 1O0 25 1.o
1O0 1O0 0.5
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Current Ranges 1O0 1.o 100% on all 0.20
B.13.2.5.1 Current Ranges
1O0 0.5 100% on ali 0.20
Current Ranges
Tilt
8.13.2.8
1O0
1O0
25
1O0
1.o
1.o
see text 0.20
0.20 U
Repeatability 1O0 25 1.o see text 0.20
8.13.2.9 1O0 1O0 1.o 0.20
The standard meter shall be placed in a space having a temperature of 23°C X2"C and allowed to stand
for not less than 2 hours with the voltage circuit energized. The meter shall then be tested with 100% of
rated current at 1.O and 0.5 power factors.
Test Condition (3): The reference standard meter shall be placed in a space having a temperature of 11°C
QoC for not less than 2 hours with the voltage circuit energized. The meter shall then be tested with 100%
of rated current at 1.O and 0.5 power factors.
Test Condition (4): Repeat condition (3), except that the reference standard meter shall be placed in a
space having a temperature of 35°C 12"c. At 11°C +2"C and 35°C +2"C the registration shall not differ
from the value at 23°C k2"C by more than the amount specified in Table 29.
Repeatability
8.13.3.7
1O0
1O0
see text
1 0.05
0.05
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Appendix C
(Normative)
Registering Mechanism and Meter Constants
for Electro-mechanical Meters
C.l General
Descriptions have been given of methods for determining the accuracy of a meter as far as the speed of the
rotor is concerned, and for physically checking register and gear ratios. It is equally important that it be
determined mathematically that the relations between the register (dial) constant, watthour constant, register
ratio, and gear ratio are correct. The register constant should always appear on the face of the register when
other than one, the register ratio will be found marked on the register or on the nameplate, and the watthour
constant usually will be found marked on the nameplate. Manufacturers generally use one standard shaft
reduction for all ratings of meters of the same type, but the information does not appear on the meter. The
gear ratio is dependent on the shaft reduction and also the register ratio. The gear ratio information also does
not appear on the meter.
C.2 Symbols
K, (watthour constant): The number of watthours per revolution of the meter rotor (disk).
y (register, or dial, constant): The multiplier used to convert the register reading to kilowatthours.
F$ (gear ratio): The number of revolutions of the rotor (disk) for one revolution of the first dial pointer.
R, (register ratio): The number of revolutions of the first gear of the register for one revolution of the first dial
pointer.
O R, (shaft reduction): The number of revolutions of the meter rotor (disk) for one revolution of the first gear of
the register.
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In some meters a single-pitch worm is used on the rotor, meshing with a worm wheel of 100 teeth on the
register, thus, the shaft reduction is 1OO. A single-pitch worm is sometimes used with a 50-tooth worm wheel
to give a shaft reduction of 50.
In others, a double-pitch worm is used on the rotor, meshing with a worm wheel of 100 teeth on the register,
thus, the shaft reduction is 50.
In still others, pinions on the rotor meshing with gears on registers result in shaft reductions of 6-1/4, 8-1/3,
etc.
Transfer gearing between the disk shaft and the register is used in a few types of meters. In some, it is of 1:i
ratio and has no effect on the shaft reduction. There are instances, however, where the transfer gearing is
either 16-î/3 to 15 or 16-2/3 to 30.
The shaft reduction may be determined from the manufacturer's literature, from tables, by counting teeth in
gears and pinions, or by test.
C.4 Formulas
When the register constant (y),watthour constant (K,,), and shaft reduction (RJ are known, the register ratio
(RJ may be determined by the following formula:
then
1 x 10,000
R, = = 27-719
3.6 x 100
-
Kh x R, x R,
= kilowatthours
1O00
R, =R,x R,
K, x Rr x R, - Kh X Rg
-
Kr = 10 x 1,000 10,000
K, x 10 x 1,000
Kh =
Rr Rs
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K, x 10 x 1,000
R, =
Kh Rr
In the foregoing formulas, 10 is the numerical value of one revolution of the first dial pointer.
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E.l Definition
For definition of a phase-shiftingtransformer, see Section 2.
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The development of such a Code with the collecting of the very large amount of necessary data was placed
in the hands of the Electrical Testing Laboratories of New York, and at the Briarcliff Convention of 1909 there
was presented the first issue of the Code, covering four sections and representingthe first year's work. As a
means of increasing the strength and support of the work, and at the same time avoiding duplication of effort
along similar lines, it was arranged with the consent of the Executive Cornmittee of both Associations to join
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hands with the Meter Committee of the National Electric Light Association (NELA) for the further development
of the Code. The second year's work, therefore, represents the combined efforts of the Meter Committees of
the two associations.
The Code to date as here presented includes with minor revisions and corrections those sections which have
been presented in the reports at the 1909 Edison Convention and the 1910 NELA Convention, and also two
entirely new sections. It is hoped that it may find its place among reliable books of reference in the hands of
those responsiblefor, and interested in, the purchase, installation,and operation of electric meters.
A considerable amount of ground still remains to be covered, and it is only to be expected that, with changes
and improvements in the art, revisions must from time to time become necessary, but it is the intention of the
Committees to continue the work to its logical conclusion.
While the Code is naturally based upon scientific and technical principles, the commercial side of metering
has been constantly kept in mind as of very great importance, and it is believed that due consideration has
been given to this phase of the problem.
Although the work has been directed very closely by the two Cornmittees, the burden of the undertaking has
been carried by the Electrical Testing Laboratories, to which full credit should be given.
The Cornmittees are indebted to Clayton H. Sharp for his personal interest and cooperation in the conduct of
the work and to W. W. Crawford, also of the Laboratories, for the zeal and discrimination which he has
displayed in preparing the drafts of the Code for the Cornmittee's consideration.
The Committees would also acknowledge most gratefully the hearty and valuable cooperation of the
manufacturing companies and particularly that of F. P. Cox and L. T. Robinson of the General Electric
Company, and William Bradshaw of the Westinghouse Electric and Manufacturing Company. It is the earnest
desire of the Committees that the Code may prove its value to all of those interested in the precise
commercial measurement of electrical energy and may contribute to the advancement of the art.
Committee personnel
AEIC NELA
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This edition of the Code for Electricity Meters is a revised and complete compilation of the sections issued
separately during the past 5 years. The revision and arrangement here have been under the supervision of
the Meter Cornmittees of the Association of Edison Illuminating Companies and the National Electric Light
Association.
Advantage was taken of the printing of the Code in complete form to make such revisions in the text and to
add such new matter as appeared desirable. The Electrical Testing Laboratoriesjoined with the Committees
in this revision and compilation as they did in the original preparation of the various sections of the Code, and
this revised edition has their approval.
The Code for Electricity Meters has been generally accepted as a standard of reference for meter practice.
Its revision, completion, and appearance in one volume enhance its value for this purpose.
Committee personnel
AEIC NELA
The sponsors hereby express their appreciation to the members of the Sectional committee and their
associates for the painstaking and careful manner in which the revision was carried out.
A preliminary draft was presented at a meeting of the Sectional committee on April 1, 1926. This draft was
approved in general outline, and referred to an editorial committee consisting of Messrs Brooks, Currier,
Doyle, Fellows, Hill, Koenig, Meyer, and Pratt. This committee carefully reviewed the draft, agreed upon a
standard form and arrangement, and appointed H. Koenig, the Secretary of the Sectional Committee, to
prepare the final draft for the printer. A considerable amount of material appearing in the Second Edition has
This Code, as revised, was submitted in galley-proof form to all the members of the Sectional Committee for
final approval by letter ballot, and it was then formally approved by each of the sponsors. The sponsors,
acting jointly, presented the Code to the American Engineering Standards Committee for approval as
American Standard, and it was so approved February 20,1928.
Committee personnel
W. M. Bradshaw F. Holmes J. Franklin Meyer
O. J. Bushnell F. A. Kartak A. L. Pierce
F. P. Cox H. Koenig G. A. Sawin
Burleigh Currier R. C. Lanphier C. H. Sharp
E. D. Doyle F. V. Magalhaes C. R. Vanneman
R. W. Easton Alexander Maxwell W. L. Wadsworth
The Sectional Committee was formally organized March 14, 1924; J. Franklin Meyer, Chairman; E. D. Doyle,
Secretary, later succeeded by H. Koenig.
The actual revision of the Code was done by four technical subcommittees, as authorized by the Section
Cornmittee. These subcommittees were:
The sectional Committee C12 which prepared the revision was as follows:
The work of revision was divided into six major sections and was done by the following six subcommittees:
O E. Kline, W. H. Pratt
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(2) Standards and Metering: H. B. Brooks, Chairman; A. S. Albright, W. M. Bradshaw, F. E. Davis, Jr.,
F. C. Holtz, H. C. Koenig, G. R. Sturtevant
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(3) Specifications for Acceptance of Types of Electricity Meters and Auxiliary Devices: W. C. Wagner,
Chairman; W. M. Bradshaw, H. B. Brooks, A. B. Craig, W. R. Frampton, E. E. Hill, H. C. Koenig, R.
H. Nexsen, W. H. Pratt
(4) Installation Methods and Watthour Meter Test Methods: O. K. Coleman, Chairman; A. P. Good,
Stanley S.Green, C. B. Hayden, N. S. Meyers, L. D. Price
(5) Laboratory and Service Tests: P. L. Holland, Chairman; J. S. Cruikshank, P. G. Elliott, J. H. Goss,
E. E. Hill, J. C. Langdell, F. L. Pavey
(6) Demand Meters: A. J. Allen, Chairman; F. C. Holtz, R. E. Johnson, E. A. LeFever, R. H. Nexsen, A.
R. Rutter, W. C. Wagner, W. H. Witherow
Many improvements and innovations in meters and their auxiliary equipment, and in metering practices, have
taken place since the Fourth Edition of the Code was issued. These developments were taken into account in
preparing the present edition. For the first time, the Code recognizes that statistical methods may be applied
to in-service testing of meters to reveal where testing and maintenance effort should be directed; and
guidance is offered toward the selection of sound statistical procedures. The other sections of the Code have
also been broadened and largely rewritten to cover other phases of electricity metering in line with the
present state of the art.
Finally, it should be noted that the name of this standard has been changed to American Standard Code for
Electricity Metering, as the committee believed that this title more accurately described the content of the
standard.
This edition of the American Standard Code for Electricity Metering was prepared by Sectional Committee
C12 of the American Standards Association. The sponsors are the National Bureau of Standards and the
Edison Electric institute.
The personnel of Sectional Committee C12 that prepared this revision of the Code wereas follows:
F. K. Harris, Chairman
A. T. Higgins, Secretary
Definitions: W. J. Piper
Measurementof Power and Energy: D. T. Canfield
Standards: F. K. Harris, Chairman; E. F. Blair
Acceptance of New Types of Meters: G. B. M. Robertson, Chairman; T. D. Barnes, E. F. Blair, J.D.
McKechnie, R. A. Road, R. S. Smith
Watthour meter Test Methods: P. W. Hale, Chairman; J. Anderson, T. D. Barnes, W. C. Downing,
Jr., H. W. Kelley, J. D. McKechnie, E. C. Nuesse, R. A. Road, F. H. Rogers
Installation Requirements: H. W. Kelley, Chairman; E. B. Hicks, H. H. Hunter, L. H. Keever, R. E.
Purucker, A. W. Rauth, L. O. Steger
InstrumentTransformers and Auxiliary Devices: J. W. Dye, Chairman; E. F. Blair, F. R. D'Entremont,
B. L. Dunfee, W. H. Farrington, H. W. Kelley
InService Tests of Watthour Meters: H. H.Hunter, Chairman; F. K. Harris, A. L. Hobson, C. L. Lucal,
J. D. McKechnie, C. V. Morey, R. E. Purucker, F. H. Rogers, L. O. Steger, G. Wey
Demand Meters (Acceptance, Test Methods, In-Service Tests); G. J. Yanda, Chairman; R. V.
Adams, W. C. Downing, Jr., P. W. Hale, F. M. Hoppe, W. J. Piper, R. A. Road, R. J. Stowel
Editorial: G. B. M. Robertson, Chairman; J. Anderson, P. W. Hale, F. K. Harris, A. T. Higgins, H. H.
Hunter, H. W. Kelley, F. H. Rogers, G. J. Yanda
O
- A new form of auxiliary device, known as a pulse recorder, has come into general use during the past 10
years. It records, on magnetic or paper tape, pulses received from pulse initiators installed on watthour or
other integrating meters. The tapes are processed by automated equipment using computer techniques, thus
reducing human errors and speeding up accounting and data-interpretation processes for both customer
billing and survey installations.
These developments as well as others have been taken into account in this edition of the Code.
Recommended periodic test intervals for modem meters have been lengthened, and sampling methods have
been extended to additional kinds of meters. In addition, performance requirements have been incorporated
for the new types of pulse devices and for the standard watthour meters used as references to maintain the
kilowatthour or to test other meters. Many other changes have been made.
This standard is a revision of American National standard Code for Electricity Metering. C12-1965. The
secretariat of American National Standards Committee C12 is held by the Edison Electric institute and the
National Bureau of Standards.
This standard was processed and approved for submittal to ANSI by the American National Standards
Committee on Code for Electricity metering, C12. Committee approval of the Standard does not necessarily
imply that all committee members voted for its approval. At the time it approved this standard, The C12
Committee had the following members:
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F. L. Hermach, Chairman
A. T. Higgins, Secretary
The work of revision was done by a number of subcommittees, and was reviewed by the C12 Standards
Committee. The assignments of these subcommittees were as follows:
Definitions, and (2) Measurement of Power and Energy: E, F. Blair, Chairman; R. S. Turgel, J. M.
Vanderieck, A. Yenkelun
(3) Standards and Standardizing Equipment: F. L. Hermach, Chairman; M. F. Borleis, W. E. Osborn, J.
Roth, E. W. Schwarz, D. M. Smith
(4) Acceptance of New Types of Watthour Meters: A. Fini, Chairman; J. Anderson, D. B. Berry, E. F.
Blair, M. F. Borieis, C.R. Colinsworth, F. G. Kuhn, D. McAuliff, G. F. Walsh
Watthour meter Test Methods: F.J. Levitsky, Chairman; J. Anderson, E. F. Blair, T. J. Pearson
Installation Requirements: B. E. Kibbe, Chairman; D. Berry, A. Browne, M. A. Frederickson. L. M.
Holdaway, H. W. Redecker
Instrument transformers and Auxiliary Devices: T. J. Pearson, Chairman; B. L. Dunfee, F. A. Fragola,
J. Landry, R. Stetson
InService Tests of Watthour Meters: H. L. Colbeth, Chairman; E. L. Barker, M. A. Frederickson, J.
Keever, J. C. Liewehr, B. Renz, C.F. Riederer, J. Suridis
(9) Demand Meter and Pulse Devices: C. R. Collinsworth, Chairman, E. C. Benbow, H. A. Duckworth,
R. Hopkins, S. C. McColum, C. F. Riederer, C. Ringold, R. J. Stowell, G. F.Walsh
Editorial: R. A. Road, Chairman; J. Anderson, F. L. Hermach, A. T. Higgins, F. J. Levitsky, W. E.
Osborn, C. F. Riederer
This standard has been enlarged to include performance specifications for a new class of self-contained
watthour meters with increased load range. The specifications for a new class of self-contained watthour
meters with increased load range. The specifications for other meters have been retained from the previous
edition without major changes, but the presentation of some of the data has been rearranged to improve
clarity. The section on standard waithour meters has also been revised to take account of the types of meters
which have come into more widespread use during the last few years. Numerous other revisions are mainly
editorial to correct errors and to bring the text into agreement with curent standard terminology.
Since 1976, the C l 2 Committee has assumed responsibilityfor developing additional standards related to the
Code for Electricity Metering, some of which were formerly issued by other organizations. By providing
mechanical and other specifications, generally not directly related to performance, these standards
complement the Code for Electricity Metering. The Code, which until this edition has been known as C12, has
now been redesignated C I 2.1. The other standards issued by the C12 Committee are listed below.
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This standard was developed by the American National Standards Cornmittee on Electricity Metering, C12,
for kill consensus approval as an American National Standard. Suggestions for improving this standard are
welcome. They should be sent to the American National Standards Institute, 1430 Broadway, New York, NY
1O018.
The Secretariat of the American National Standards Cornmittee C I 2 on Electricity Metering is held by the
Institute of Electrical and Electronics Engineers and the National Bureau of Standards. At the time this
standard was processed and approved, the C12 Committee has the following members:
R. S. Turgei, Chairman
V. Condello, Secretary
J. Anderson
J. C. Arnold, Jr.
D. B. Berry
W. C. Bush
C.R. Coliinsworth
T. C. Drew
M. Faser
R. Fowler
F. J. Levitsky
J. C. Liewehr
A. Loika
D. McAuliff
C.F. Mueller
C.F. Fiederer
c. six
G. F. Walsh
V.J. Yanakieff
The following Subcommittees of ANSI C i 2 were actively involved in the revision of this standard. The
assignments of these subcommittees were as follows:
(3) Standards and Standardizing Equipment: R.S. Turgel, Chairman; W. C.Busch, P. Cunningham,
R. E. Koil, F J. Levitsky, R. H. Stevens
(4) Acceptance of New Types of Watthour Meters: A. Fini, Chairman; J. Anderson, A. G. Ashenbeck,
Jr., D. F. Becker, C.R. Coilinsworth
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This standard was developed by the Accredited Standards Committee on Electricity Metering, C12, for full
consensus approval as an American National Standard. This revised edition supersedes ANSI C12.1-1982.
Suggestions for improving this standard are welcome. They should be sent to the American National
Standards Institute, 1430 Broadway, New York, NY 10018.
The technical content of this standard has been brought up to date, and the changes affect nearly all
chapters. In addition, following IEEE editorial policy aimed at avoiding duplication of similar or identical
requirements in their standards, those sections of text from other IEEE standards that had been incorporated
in the previous edition of C12.1 were replaced by appropriate references to those standards.
The other related standards that the C12 Committee has issued, and is continuing to issue, are listed below:3
C12.6-1987, American National Standard for Marking and Arrangement of Terminals for
Phase-ShiRing Devices Used in Metering.
C12.8-1981, American National Standard for Test Blocks and Cabinets for Installation of
Self-contained 'YI'' Base Watthour Meters.
C I 2.1 I-1987, American National Standard for Instrument Transformers for Revenue Metering, 1O kV
BIL Through 350 kV BIL (0.6 kV NSV Through 69 kV NSV).
C12.13-1985, American National Standard ke-of-Use Registers for Electromechanical Wafthour Meters.
C12.14-1982, American National Standard for Magnetic Tape Pulse Recorders for Electricity Meters.
The Secretariat of the Accredited Standards Committee on Electricity Metering, C12, is held by the Institute of
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Electrical and Electronics Engineers and the National Institute of Standards and Technology. At the time this
standard was processed and approved, the C12 Committee had the following members:
These publications are available from the Service Center, Institute of Electrical and Electronic Engineers,
445 Hoes Lane, P.O. Box 1331, Piscataway, NJ 08855-1331, or from the Sales Department, American
National Standards Institute, 1430 Broadway. New York, NY 10018.
The following subcommittees of C12 were actively involved in the revision of this standard:
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H. L. Friend
F. J. Levitsky
R. H. Stevens
In addition to the Committees listed above, C12 also has the following subcommittees:
Subcommittee Chairman
The existing standard C12.1 has been rewritten with the intent to bring it up to date in an industry that is
changing dramatically, due in part to technology and economics. The standard has been significantly
reorganized to encompass all metering devices excluding instrument transformers, providing a more logical
Row. The review team has added tests to help insure new electronic equipment is capable of providing the
dependability existing devices have shown.
Areas of the standard dealing with user testing were rewritten to allow more flexibility for individual users
while maintaining current effectiveness. Proven reliability of today's equipment as well as the consistency of
new metering equipment was used as the basis to redefine how, where, and when testing can be
accomplished. The section dealing with standards and standardizing equipment has been revised to be more
in line with current procedures while maintaining existing methods if applicable.
In addition, an effort was made to align this standard with international standards and make reference to
these standards where possible. The existing standard was broadened to include tests and requirements for
all metering, while leaving other standards to provide the details for their specific devices, to avoid
duplication. Parts of the existing standard that were viewed as user practices, not standards, were removed
or placed into the appendices as examples or for references.
The Secretariat of the Accredited Standards Committee on Electricity Metering, C12, is held by the National
Electrical Manufacturers Association (NEMA) and the National Institute of Standards and Technology. At the
time this standard was processed and approved, the C12 Committee had the following members:
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R. S. Turgel, Chairman
C. F. Merher, Secretary
James Schlatter
John Lauletta
Warren Germer
Rural ElectrificationAdministration
Edmund Hoffman
Ahn Mai
The following members of the C12 Ad Hoc Committee to Revise C12.1 were actively involved in the
revision of this standard:
T. C. Drew, Chairman
J. D. Blackmer J. Mining
B. Cook L. Pananen
W. Germer G. Powers
R. C. Guenther E. Schwarz
R. Jannelli J. H.Schlatter
M. Keyes C.J. Smith
E. Malemezian R. H. Stevens
J. Martin P. Taylor
G. Maflield D. Williams
K. McDonald C.S.Weimer
F. Scott G. Wren
J. McEvoy
H. Millican
In addition, the following comprised the Editorial Committee for the Revision of C12.1:
G. Belcher C. J. Smith
E. Malemezian R. S.Turgel