,i .i .

~\
~)I J ~).:ill;i~\~\.l\1 w~I~1

SECTION 16060:

GUIDELINE SPECIFICATION FOR

GROUNDING AND BONDING

0 31/01/06 I Issued for Use

REV DATE DESCRIPTION PREPARED BY RC APPROVED

KINGDOM
OFSAUDIARABIA ~~~1 4J.}!J1
~1
RoyalCommissionfor Jubail & Yanbu cw.4~~1~1
 SECTION 16060
GROUNDING AND BONDING

TABLE OF CONTENTS

Item No Title Page No

PART 1 GENERAL............................................................................................................ 1

1.01 DESCRIPTION OF WORK .................................................................................. 1

1.02 SECTION INCLUDES .......................................................................................... 1

1.03 RELATED SECTIONS ......................................................................................... 1

1.04 REFERENCES..................................................................................................... 2

1.05 SUBMITTALS....................................................................................................... 3

1.06 DEFINITIONS ...................................................................................................... 3

1.07 QUALITY CONTROL ........................................................................................... 5

1.08 HEALTH AND SAFETY CONSIDERATIONS...................................................... 5

1.09 FACTORY TESTING ........................................................................................... 6

1.10 SERVICE CONDITIONS...................................................................................... 6

1.11 DELIVERY, HANDLING AND STORAGE ........................................................... 7

PART 2 PRODUCTS ......................................................................................................... 8

2.01 GENERAL ............................................................................................................ 8

2.02 GROUNDING CONNECTIONS ........................................................................... 8

2.03 GROUND RODS.................................................................................................. 9

2.04 GROUNDING AND BONDING CONDUCTORS ............................................... 10

PART 3 EXECUTION ...................................................................................................... 13

3.01 GENERAL .......................................................................................................... 13

3.02 INSTALLATION OF GROUNDING SYSTEM .................................................... 13

3.03 TESTING AND COMMISSIONING.................................................................... 20

Rev 0 i Contract No:

 SECTION 16060
GROUNDING AND BONDING

PART 1 GENERAL

1.01 DESCRIPTION OF WORK

A. This Section specifies the minimum technical requirement for design engineering,
manufacture, inspection, testing and performing of grounding system using bare
copper or insulated copper conductor and bonded copper or copper clad steel
ground rod as indicated on Contract Drawings and Documents.

B. The function of the system grounding is:

1. To provide low fault impedance to the ground fault currents for prompt and
consistent operation of protective devices during a ground fault, and to limit
potential rise of electrical equipment.

2. To stabilize system neutral potential only for the system with neutral
grounding.

3. To provide means to carry electric currents into the ground under normal and
fault condition without exceeding any operating and equipment limits or
adversely affecting continuity of services.

4. To assure that a person in the vicinity of grounded facility is not exposed to the
danger of critical electric shocks.

C. Where Works interface with Saudi Electricity Company (SEC) the

equipment/materials and installation system shall comply with latest revision of SEC
standards, and shall be reviewed and approved by SEC.

1.02 SECTION INCLUDES

A. Grounding Connections

B. Grounding Rods

C. Grounding and Bonding Conductors

1.03 RELATED SECTIONS

A. Section 01320 Construction Progress Documentation

B. Section 01330 Submittal Procedures

C. Section 01450 Quality Control

D. Section 01650 Product Delivery Requirements

E. Section 01660 Product Storage and Handling Requirements

F. Section 02080 Utility Material

Rev 0 1 of 20 Contract No:

 SECTION 16060
GROUNDING AND BONDING

G. Section 02580 Electrical and Communication Structures

H. Section 11080 Registration Equipment

I. Section 16055 General Provision of Low Voltage Electrical Works

J. Section 16120 Conductors and Cables

K. Section 16130 Raceway and Boxes

L. Section 16220 Motors and Generators

M. Section 16270 Transformers

N. Section 16290 Power Measurements and Controls

O. Section 16340 Medium Voltage Switching and Protection Assemblies

P. Section 16440 Switchboards, Panelboards and Control Centers

Q. Section 16510 Interior Luminaries

R. Section 16520 Exterior Luminaries

S. Section 16710 Communication Circuits

T. Section 16720 Telephone and Intercommunication Equipment

U. Section 16726 Installation of Telecommunication Facilities

V. Section 16780 Broadcast Transmission and Reception Equipment

1.04 REFERENCES

A. The following codes and standards are intended to provide an acceptable level of
quality for materials and products. In case of conflict between these standards and
the text of this Specification, the Specification text shall govern.

B. The latest revision of the following codes and standards shall be used wherever
applicable. In case of conflict, the Contractor shall propose equipment conforming to
one group of codes and standards.

C. ASTM American Society for Testing and Materials

1. ASTM B3 Standard Specification for Soft or Annealed Copper

Wire

2. ASTM B8 Standard Specification for Concentric-Lay-Stranded

Copper Conductors, Hard, Medium-Hard, or Soft

3. ASTM B33-00 Standard Specification for Tinned Soft or Annealed

Copper Wire for Electrical Purposes

Rev 0 2 of 20 Contract No:

 SECTION 16060
GROUNDING AND BONDING

4. ASTM B910/910M Standard Specification for Annealed Copper Clad

Steel Wire

D. IEEE Institute of Electrical and Electronics Engineers

1. IEEE C.57.13.3 Grounding of Instrument Transformer Secondary

Circuits and Cases

2. IEEE 80 Guide for Safety in Alternating-Current Substation

Grounding

3. IEEE 81 Guide for Measuring Earth Resistivity, Ground

Impedance, and Earth Surface Potentials of a
Ground System

4. IEEE 81.2 Guide for Measurement of Impedance and Safety

Characteristics of Large, Extended or Interconnected
Grounding Systems

5. IEEE 142 Recommended Practice for Grounding of Industrial

and Commercial Power System

6. IEEE 837 Qualifying Permanent Connections Used in

Substation Grounding

7. IEEE 1246 Guide for Temporary Protective Grounding System

Used in Substations.

E. IEC International Electro-Technical Commission

1. IEC 60076-3 Power Transformers-Part 3: Insulation Levels,

Dielectric Tests and External Clearances in Air

F. NFPA National Fire Protection Association

1. NFPA 70 National Electrical Code

G. UL Underwriters Laboratories, Inc.

1. UL 44 Thermoset-Insulated Wires and Cables

2. UL 83 Thermoplastic-Insulated Wires and Cables

3. UL 467 Grounding and Bonding Equipment

4. UL 486 A Wire Connectors and Soldering Lugs for Use with

Copper Conductors

1.05 DEFINITIONS

A. bonding: The permanent joining of non-current carrying metallic parts and or circuit
conductors intended to be grounded to grounding conductors to ensure a reliable

Rev 0 3 of 20 Contract No:

 SECTION 16060
GROUNDING AND BONDING

electrically conductive path to ground, which will provide electrical continuity and the
capacity to conduct safely any current likely to be imposed.

B. bonding jumper: A reliable conductor, solidly connected, between non-current-

carrying metal parts or circuit conductors or both intended to be grounded.

C. cable bond: An electric connection across a joint in the armor or lead sheath of a
cable, or between the armor or sheath of adjacent cable.

D. equipment ground: An electrical ground connection intentionally made to exposed

non-current-carrying metal parts of fixed equipment, enclosures and raceways
containing electrical conductors likely to become energized. The connection is made
to provide a reliable low-impedance fault return path that will facilitate the operation
of overcurrent devices under ground-fault conditions and protect personnel from
dangerous voltages and currents.

E. ground: A conducting connection, whether intentional or not, between an electrical

circuit or equipment and the earth or to some conducting body that serves as the
earth.

F. ground electrode: A bare cable, ground rod, plate, or groups of these in intimate
contact with the ground for the purpose of providing a connection to a ground.

G. grounded: Connected to earth or to some conducting body that serves in place of

earth.

H. grounded conductor: A system or circuit conductor that is intentionally grounded.

I. grounding conductor: A conductor used to connect a piece of equipment, a device,

or the grounded circuit conductor of a wiring system to a grounding electrode or
electrodes.

J. grounding electrode conductor: A conductor connecting the grounding electrode

to an equipment grounding conductor or to a grounded conductor or both at the
service equipment or at the source of a separately derived system.

K. system or circuit ground: An electrical ground connection intentionally made to

system or circuit conductors to limit voltages due to lightning, line surges, or
unintentional contact with higher voltage lines and to stabilize the voltage to ground
during normal operation.

1.06 SUBMITTALS

A. The Contractor shall submit to the Royal Commission, under the provisions of
SECTION 01330, the following items for review and approval before commencing
Work:

1. All vendor drawings and products data sheets and Specifications shall be
generally provided as defined and particularly as listed below:

a) List of Manufacturers.

b) Manufacturer’s catalogues including installation instruction for grounding

Rev 0 4 of 20 Contract No:

 SECTION 16060
GROUNDING AND BONDING

conductors, grounding rods and accessories.

c) Material submittals complete with comparison sheets, and components

list of offered materials.

d) Quality Control Program as referenced in SECTION 01450.

e) Factory Test Reports.

f) Samples of grounding conductors, grounding rods and accessories for

approval by the Royal Commission.

g) Certificates of compliance.

h) Calculations for sizing of grounding conductors, material and grounding

rods.

i) Soil Resistivity measurements.

j) Design of Grounding System.

B. The Contractor shall submit Field Test Reports after completion of testing and
commissioning.

1.07 QUALITY CONTROL

A. The Contractor shall be responsible for the quality of work and shall develop and
propose programs and methods of construction and testing such as to achieve the
specified quality to the approval of the Royal Commission in accordance with
SECTION 01450.

1.08 HEALTH AND SAFETY CONSIDERATIONS

A. All works undertaken in relation to this Specification are to be completed in full

accordance with the respective health and safety requirements established by the
following:

1. Kingdom of Saudi Arabia

a) Legislation, Regulation. Standards and Codes.

2. Royal Commission Regulations

a) Standards, Contractual Conditions, and Health and Safety Systems.

3. Contractor

a) Health and Safety Standards and systems accepted by the Royal

Commission.

Rev 0 5 of 20 Contract No:

 SECTION 16060
GROUNDING AND BONDING

B. In the absence of any of the above, best accepted industry practice shall be
employed throughout.

1.09 FACTORY TESTING

A. General

1. All the Grounding Conductors and Grounding Rods shall be tested at the
factory in accordance with the latest approved manufacturing codes and
standards. The Contractor shall notify to the Royal Commission in writing not
less than 30 days prior to the scheduled starting date of the factory tests.

2. The Royal Commission reserves the right of deputing their representative for
witnessing the factory tests.

3. Upon completion of factory tests, and before shipment of the Grounding

Conductors and Grounding Rods, the Contractor shall submit 5 certified copies
of test reports not later than 10 days after the completion of all factory tests for
review and approval by the Royal Commission.

1.10 SERVICE CONDITIONS

A. All the Grounding materials installed indoors shall be suitable for continuous
operation under the following service conditions:

1. Ambient air temperature:

a) A maximum of 40°C.

b) A minimum of 0°C.

c) Average temperature, measured over a period of 1 month, is a

maximum of 35°C.

2. Relative humidity (average value):

a) For a period of 24 hours, does not exceed 95%.

b) For a period of 1 month, does not exceed 90%.

B. All the Grounding materials installed outdoor shall be suitable for continuous
operation under the following service conditions:

1. Ambient air temperature:

a) A maximum of 50°C.

b) A minimum of 0°C, unless a lower temperature is specified in the

Contract Drawings and Documents.

c) Average temperature, measured over a period of 1 month, is a

Rev 0 6 of 20 Contract No:

 SECTION 16060
GROUNDING AND BONDING

maximum of 45°C.

2. Altitude is less than 1000 m, unless a higher altitude is specified on the

Contract Drawings and Documents.

3. Average value of the relative humidity:

a) For a period of 24 hours, does not exceed 95%.

b) For a period of 1 month, does not exceed 90%.

4. Relative humidity may be temporarily 100%.

C. All the Grounding materials to be installed in classified areas as indicated on the

Contract Drawings and Documents shall be suitable for such installation as per NEC
Article 500 or other relevant standards, as specified in par. 1.04.

1.11 DELIVERY, HANDLING AND STORAGE

A. The Contractor shall deliver, handle and store materials and equipment in
accordance with SECTIONS 01650 and 01660, as well as the following
requirements:

1. Delivery of materials and equipment to site originally packed, securely

wrapped and labeled by manufacturer in unopened containers. Protect
materials during delivery by complying with manufacturer’s directions.

2. Store materials at building site strictly according to manufacturer’s instructions.

Store products or equipment in dry, clean and ventilated place.

3. Avoid damage or distortion of the materials during handling and shipment or

transportation.

4. The Contractor shall be responsible for any damage to the materials or

equipment during storage, handling and transportation.

Rev 0 7 of 20 Contract No:

 SECTION 16060
GROUNDING AND BONDING

PART 2 PRODUCTS

2.01 GENERAL

A. All goods and products covered by this Specification shall be procured, when
available from an in-Kingdom manufacture. However procurement of all goods and
products manufactured out-of-Kingdom or in kingdom must be approved by the Royal
Commission.

2.02 GROUNDING CONNECTIONS

A. Following are the types of grounding connections which shall be commonly used in
industrial and commercial grounding systems:

1. Mechanical Connections.

2. Compression Connections.

3. Exothermic Connections.

B. Mechanical Connections

1. The mechanical connections of the conductors shall be done by using

mechanical connector bodies manufactured from high strength; high
conductivity cast copper alloy material. Bolts, nuts, washers and lock washers
shall be made of silicon bronze and supplied as a part of the connector body
and shall be of the 2-bolt type.

2. All bolted and compression joints shall withstand a maximum temperature of

250°C.

3. For outdoor equipment or structures above grade, joints of pigtails with the
respective connectors shall be compression (Lug) type and the connectors in
turn shall be bolted to the respective equipment.

4. Split bolt connector types are not allowed.

5. The connectors shall meet or exceed the relevant standards as specified in

par. 1.04 and be clearly marked with the catalog number, conductor size and
manufacturer’s name.

C. Compression Connections

1. The compression connections shall be done by using compression connectors

manufactured from pure wrought copper. The conductivity of this material shall
not be less than 99% by International Annealed Copper Standards (IACS).

2. The installation of the connectors shall be made with a compression, tool and
die system, as recommended by the manufacturer of the connectors.

3. The connectors shall be clearly marked with the manufacturer, catalog

number, conductor size and the required compression tool settings.

Rev 0 8 of 20 Contract No:

 SECTION 16060
GROUNDING AND BONDING

4. Each connector shall be factory filled with an oxide-inhibiting compound.

5. The connectors shall meet or exceed the relevant standards as specified in

par.1.04 and 2.02 B. 5.

D. Exothermic Connections

1. Exothermic welding system shall be used in making electrical grounding

connections between copper-to-copper and copper-to-steel. Exothermically
welded connections are required on all grounding electrode conductors, all
connections to building steel (connections to structural member), all grounding
conductors run under the earth, connection to ground rods and in any case
where grounding conductors are subject to a hostile environment.

2. Exothermic welded joints shall be used on buried ground grids (cross over
points etc) which make the connections as integral part of the homogenous
conductor.

3. All joints that are part of the ground grid net work shall be exothermic.

4. All exothermic connections shall be bit mastic painted and mastic taped.

5. The exothermic welding system furnished under these Specifications shall

meet the applicable requirements of relevant standards as specified in par.
1.04.

6. Molds shall be made from graphite or other material that is so designed to

provide an average life of not less than 50 exothermic welds under normal
conditions. Molds shall bear permanent marking, indicating the name of the
manufacturer, the mold model, the type and size of welding mixture compatible
with the welding process, and the size of the conductor. Instructions detailing
general safety information, and welding procedures shall be provided with
each mold.

7. Starting material, if used, shall consist of aluminum and copper/copper oxide

and iron oxides. It shall not contain phosphorous or any caustic, toxic or
explosive substance. Weld metal used for grounding connections shall contain
copper oxide, aluminum. Smokeless exothermic welding process shall be used
for welding done in enclosed structures.

2.03 GROUND RODS

A. General

1. The bare copper/copper clad steel ground rods shall meet or exceed the
requirements of relevant standards as specified in par. 1.04.

2. The bare copper/copper clad steel ground rod shall have a minimum diameter
of 16 mm or as per design calculations and a minimum length of 3 m. The
ground rod shall be of sectional type equipped with suitable couplings and
driving studs.

3. The material of ground rods shall have a pure copper covering, permanently

Rev 0 9 of 20 Contract No:

 SECTION 16060
GROUNDING AND BONDING

joined to a high-strength steel core. The steel core shall have sufficient rigidity
for easily driving into ground with hammer or mechanical drivers.

4. The minimum thickness of copper covering for copper-clad ground rod shall
not be less than 0.25 mm.

5. The actual diameter of the copper-clad steel rod shall not be less than
14.3 mm (unthreaded) or as per design calculations.

2.04 GROUNDING AND BONDING CONDUCTORS

A. General

1. Conductors shall be either insulated or bare, used as grid conductors,

grounding electrode conductors, equipment ground conductors, or bonding
conductors in grounding system.

2. Grounding and bonding conductors shall be soft annealed solid or concentric-

lay stranded bare copper class B, 600 V, in accordance with ASTM B3 and B8.

3. Bare or insulated copper conductor size 10 sq mm (No. 8 AWG) and above

shall be stranded per ASTM B8.

4. For the application of grounding and bonding of various equipment used in

industrial, commercial and residential buildings, control circuits, machine tools
and appliances, the conductor insulation shall comply with the following
characteristics:

a) Insulation shall be heat and moisture resistant, polyvinyl chloride

meeting the requirements of UL 83 for type THHN/THWN wires.

b) Nylon jacket shall be applied directly to the surface of the PVC

insulation.

c) The nylon and insulation thickness shall also meet the requirements of
UL 83.

d) The insulation is acceptable for use in locations at 90°C dry or 75°C wet.

5. For the application of grounding and bonding of various equipment used in

switch boards, lighting and power circuits in residential and commercial
buildings. Also for industrial plants and utility substations as well as control
circuits, the conductor insulation shall comply with the following characteristics:

a) Insulation shall be flame retardant, abrasion, heat and moisture resistant

thermoset, meeting the requirements of UL 44 for type XHHW wires.

b) Cable shall be provided with a sunlight resistant polyvinyl chloride

jacket, the average thickness of insulation shall be as specified in UL 44
for type XHHW, the minimum thickness at any point shall be not less
than 90% of the specified thickness.

c) The temperature rating shall be same as specified in par. 2.04. A. 4. d.

Rev 0 10 of 20 Contract No:

 SECTION 16060
GROUNDING AND BONDING

d) Wire shall be tested in accordance with specified UL standards 44 for

type XHHW.

B. Cable Marking and Identification

1. The jacketed cable shall be marked as specified in SECTION 16120.

2. Each end of the bare soft annealed copper grounding conductor in the reel
shall bear a non-corroding tag identifying the following:

a) Grade of grounding conductor.

b) Diameter/Size of grounding conductor.

c) Average Breaking Strength.

d) Length of grounding conductor.

e) Stranding.

3. Each reel shall be stenciled to show all information as specified in par. 2.04.
B. 2. plus additional information as follows:

a) Manufacturer’s Name and Country of Origin.

b) Year of Manufacture.

c) Serial Number.

d) Size of Reel.

e) Gross weight.

f) Consignee Address.

g) Direction of Rolling.

4. All markings shall appear on both sides of the reel.

5. Color identification of insulated grounding conductors shall be in accordance

with article 250 of NEC.

C. Conduits

1. For more details, refer to SECTION 16130.

D. Test Wells

1. The Contractor shall furnish optional grounding test wells in accordance with
the Contract Drawings and Documents, either concrete reinforced or readily
available approved test wells. The well cover shall be cast iron or hard plastic
with legend “GROUND ROD” or “EARTH ROD” embossed on cover. Refer to
SECTIONS 02580 and 02080.

Rev 0 11 of 20 Contract No:

 SECTION 16060
GROUNDING AND BONDING

2. Before installation of any type of test wells, the Contractor shall take an
approval from the Royal Commission.

Rev 0 12 of 20 Contract No:

 SECTION 16060
GROUNDING AND BONDING

PART 3 EXECUTION

3.01 GENERAL

A. The Contractor shall provide all materials, equipment and labor as deemed
necessary to show proper execution of the Work.

3.02 INSTALLATION OF GROUNDING SYSTEM

A. General

1. All installation details, write up on handling of the equipment, instruction

manuals and latest revised drawings furnished by manufacturer shall be
available at site prior to installation of the equipment. These details shall be
reviewed by Royal Commission’s representative. The details and instructions
furnished in these documents shall be followed carefully during installation of
the equipment.

2. All the facilities required for transportation of equipment/materials from store to

site such as competent manpower, trucks and crane of adequate capacities
shall be supplied by the Contractor.

3. All equipment moved to the site shall be inspected for damage or deterioration
during storage.

B. Installation

1. Grounding system shall be installed as indicated on the Contract Drawings and

Documents, and in accordance with the applicable codes and standards as
specified in par.1.04.

2. Grounding conductors shall be installed continuously, between equipment and

grounding electrodes.

3. When required, grounding conductors shall be installed in PVC conduit or rigid

galvanized steel conduit as specified on the Contract Drawings.

4. Above ground, connections shall be made with listed compression, mechanical

connectors and bolted to flat surfaces.

5. Screws and bolts for grounding and bonding connectors and terminals shall be
tightened according to torque-tightening values specified in UL 486A, or as per
the manufacturer’s recommended values.

6. Hydraulic compression tools shall be used to provide correct circumferential

pressure for compression connectors. Tools and dies recommended by
manufacturer of connectors shall be used.

7. Below ground, connections to grounding grids and ground rods or between

conductors and/or grounding rods shall be made by using listed exothermic
connections.

Rev 0 13 of 20 Contract No:

 SECTION 16060
GROUNDING AND BONDING

8. The number of grounding rods to be installed shall be determined after

computing the specific value of grounding resistance.

9. Each grounding rod shall be driven vertically in the earth up to the depth not
less than 3000 mm. Where permanently concealed ground connections are
required, make the connections by the exothermic process to form solid metal
joints. Make accessible ground connections with listed grounding connectors.

10. Ground rod shall be installed with their top, 500 mm minimum below grade and
bonded to the grounding conductor or grid by thermo weld process as
indicated on the Contract Drawings and Documents.

11. Prior to backfilling, the installation of the ground rods shall be accomplished.

12. The maximum acceptable values of grounding system resistance to ground

shall not exceed 5 ohms, and the ground resistance measurements shall be
made as defined in standard as specified in par. 1.04.

13. If the grounding resistance values exceed 5 ohms, the Contractor shall install
additional ground rods as required to achieve specified resistance. Before
installation of these ground rods at indicated locations, the Contractor shall be
required to take approval by the Royal Commission.

14. Shielded power cables shall have its ground wire at each termination in a
manner recommended by the cable manufacturer and the grounding
connection shall be made in accordance with the Contract Drawings and
Documents using the suitable connectors.

15. Grounding conductors extending through concrete or asphalt shall be run in

PVC conduit (preferred) or PVC coated rigid steel conduit or as specified on
the Contract Drawings and Documents.

16. The lightning protection system shall be bonded to the electrical grounding
electrode system in accordance with the code as specified in par. 1.04.

17. Compression or equally approved type connectors shall be used for

connecting conductors. Connections between conductors and ground rods at
test wells shall be made with bolted and clamped type connectors or equally
approved connectors.

18. Types and sizes of the grounding and bonding conductors, if not indicated on
the Contract Drawings and Documents, shall be selected from relevant codes
and standards as specified in par.1.04.

C. Structure and Equipment Grounding Requirements

1. Steel Structure and Switch Racks

a) Switch racks and every steel structure that supports insulators of

electrical equipment shall be grounded by means of bolted connections
at 2 diagonally opposite legs. Equipment mounted on steel supporting
structures shall have separate grounding conductors.

b) Electro-mechanical equipment such as generators and motors, including

Rev 0 14 of 20 Contract No:

 SECTION 16060
GROUNDING AND BONDING

duct work, building steel, enclosures, raceways, junction boxes, outlet

boxes, cabinets, machine frames, metal equipment platforms which
support any electrical equipment and other conductive items in close
proximity with electrical circuits, shall be grounded and bonded to the
nearest grounding grid in accordance with the code and standards as
specified in par. 1.04., and as per the Contract Drawings and
Documents.

2. Fence and Gates

a) The perimeter ground conductor and the fence shall be bonded

electrically at corner posts, gateposts and every alternate line post. The
gate shall be bonded to the gateposts with flexible copper cable or braid.

3. Cables

a) Metallic cable sheaths shall be effectively grounded by connecting a

flexible braid to the sheath to eliminate dangerous induced voltages to
ground. Metallic sheath of control cables shall be grounded at both ends
to the grounding grid via ground bus bar in the cubicle.

4. Cable Tray System

a) Cable tray system shall be grounded with bare copper conductor of

50 sq mm size at both ends and shall be bonded across gaps including
expansion gaps.

5. Metal Buildings

a) Metal buildings shall be grounded at each structural column with a

minimum size of 120 sq mm bare copper conductor.

b) Angle irons installed on indoor trenches to support the metallic covers

shall also be grounded at both ends.

c) Metallic doors in substation buildings shall be grounded with flexible

copper cable or braid.

6. Circuit Breakers and Disconnect Switches

a) All circuit breakers and disconnect switches enclosures shall be

grounded at two diagonally opposite corners from two separate points of
the grounding grid.

b) Further grounding switch blades of the Disconnect Switch shall be

directly grounded to grounding grid. Good electrical connection shall be
maintained between the steel structure and any bolted accessories
mounted on it.

7. Operating Handles for Outdoor Switches

a) A large percentage of fatal accidents from voltage gradients are

associated with manual operating handles of disconnect switches, etc.

Rev 0 15 of 20 Contract No:

 SECTION 16060
GROUNDING AND BONDING

b) A metal grounding plate or mat (operating platform), shall be placed

where the operator must stand on it to operate the device. The operating
handles shall be grounded by connecting a ground conductor
(preferably flexible wire, braid strap) from the vertical operating pipe to
the supporting structure, then continuing another stranded ground
conductor to the switch operating platform. It is reiterated that the
operating handle and the platform shall not be directly connected to the
grounding grid but instead both connected to the support structure which
in turn shall be connected to the grounding grid at least at two diagonally
opposite points.

8. Terminal Transmission Tower Grounding

a) Terminal transmission towers located adjacent to the substation shall be

connected to the substation grounding grid at two diagonally opposite
points. The shield wire shall be connected to the tower structure, which
in turn is connected to the grounding grid as discussed above.

9. Lightning Masts

a) Metal lightning masts shall have one safety ground.

10. Oil Tanks and Oil / Water Piping

a) All oil tanks shall be grounded at two points with bolted cable
connections to two different points of the grounding grid. Oil piping shall
be grounded at intervals of 12 m. Runs shorter than 12 m shall be
grounded at least at two points.

b) Water piping shall be connected to the grounding system at all service

points. In addition, two copper conductors of adequate size shall be
connected to the main water pipe from two separate points of the
grounding grid.

11. Metal Clad Switchgear

a) Metal Clad Switchgear shall have two safety grounds connected to the
switchgear grounding bus. Withdrawable circuit breakers and PTs shall
be provided with reliable connection to the ground bus. Grounding via
the roller wheels and the rail is not acceptable.

12. Grounding of Lighting Equipment

a) Grounding of the lighting fixtures, lamp holders, lamps, receptacles and

metal poles supporting lighting fixtures shall be per Articles 250 and 410
of NEC.

b) Portable electrical equipment shall be grounded in accordance with the

applicable requirements of Article 250 of the NEC.

13. Temporary Grounding

a) All the components used for temporary protective system shall be sized
as per calculation. All other requirements of temporary grounding shall

Rev 0 16 of 20 Contract No:

 SECTION 16060
GROUNDING AND BONDING

meet IEEE 1246.

14. Instruments, Relays and Meters

a) Instruments, meters and relays shall be grounded in accordance with

the requirements of the NEC, Articles 250.

15. Equipment Requiring both Safety and System Grounds

a) All operating grounds shall have their connections made to the

grounding rods, which in turn shall be connected to the grounding grid.

b) Power Transformers
1) Power transformer tanks shall be safety grounded at two points
diagonally opposite to each other. These connections shall be
made from two different points of the grounding grid.
2) A separate system ground shall be provided for the neutral of the
transformer by means of 2 stranded copper wires. The neutral
copper wire shall be sized for the system fault level.
3) The neutral grounding wires shall be insulated from the
transformer tank by support insulators mounted on the tank wall
and shall be connected to the grounding grid directly.
4) Independently mounted radiator bank and Low Pressure Oil
Field/Cross Linked Polyethylene (LPOF/XLPE) cable termination
boxes shall be separately grounded at two diagonally opposite
locations.
5) Tertiary windings and stabilizing windings shall be grounded per
IEC 60076-3, Annexure B.

c) Instrument Transformers
1) Potential and current transformers shall have their metal cases
grounded.
2) The grounding terminal of the potential transformers shall be
connected to the grounding grid. The neutral point of the
secondary connections of potential and current transformers shall
be grounded to the ground grid in the control/relay room instead
of switchyard to reduce the transient over-voltages. Other
requirements of instruments transformer grounding shall be as per
IEEE C57.13.3.

d) Surge Arresters
1) Where surge counter and leakage current indicating meters are
installed, a 5 kV insulated cable shall be used between arrester
ground terminal and surge counter/meter. The surge monitor's
ground terminal shall be connected to the ground grid via two 240
sq mm stranded copper conductors.
2) The system ground conductor shall be as short as possible, free
of sharp bends, and shall not be installed in metallic conduit. In
addition, ground rods shall be driven adjacent to the arrester

Rev 0 17 of 20 Contract No:

 SECTION 16060
GROUNDING AND BONDING

connection to the grounding grid to provide the lowest ground grid

resistance at this point.

e) Station Auxiliary Transformer

1) Station auxiliary transformer tank shall be safety grounded at one
location only. One system ground shall be directly connected to
the neutral bushing of wye connected windings that are to be
solidly grounded.

f) Shunt Capacitors
1) Shunt capacitors are considered safety grounded when mounted
on a metal structure that is connected to the grounding grid. One
system ground conductor shall be connected to the grounding grid
when the capacitors are to be connected in a grounded star
configuration.

g) Coupling Capacitor Voltage Transformers (CCVTs)

1) The grounding terminal and neutral point of secondary
connections of CCVT shall be connected to the grounding grid
similar to potential transformer as specified in par. 3.02 C.15.c.2.

D. Utility Grounding Requirements

1. General

a) Hazards from external transferred voltages are best avoided by using

isolating or neutralizing devices and by treating and clearly labeling
these circuits, pipes, etc., as being equivalent to live lines. The isolation
devices or the insulation provided must be capable of withstanding the
magnitude of the transferred voltage.

2. Communication Circuits

a) For communication circuits, protective schemes involve the use of

protective devices to safeguard personnel and communication terminal
equipment. Communication Master Ground Bar shall be bonded to
station grounding grid. Modern approach, however, favors the use of
fiber optic circuits, which eliminate the transfer of high voltages.

b) Bond telecommunications equipment grounding system including fire

detection and paging system to the electrical grounding grid in
accordance with Contract Drawings and Document.

3. Rails

a) Hazards can be avoided by installing several insulating joints in the rails

leaving the grid area (if applicable).

4. Utility Pipes and other Pipelines

a) All metallic utility pipes and other metallic pipelines such as rain water
pipe lines shall always be tied to the substation's grounding system. To

Rev 0 18 of 20 Contract No:

 SECTION 16060
GROUNDING AND BONDING

ensure that Ground Potential Rise (GPR) is not transferred outside the
substation plot area, all metallic utility pipes and other pipelines
emanating out of the substation shall be provided with insulated
connection at the point of leaving the substation. Necessary proposal
shall be submitted to Royal Commission for approval.

5. Auxiliary Buildings

a) Buildings relatively close to the substation, especially if linked to it via

water pipes, cable sheaths, etc., must be treated as a part of the
substation, and shall be grounded using the same safety criteria as the
substation.

6. Portable Equipment

a) It is a common practice to isolate the supply circuits for portable

equipment and their associated tools from the substation ground to
avoid a hazardous transferred voltage, which otherwise might appear
between the equipment and the nearby ground. For this purpose,
separate grounds are provided at the site of work or portable generators
may be used.

E. Underground Distribution System Grounding

1. Duct Bank

a) Grounding conductor with at least 50% ampacity of the largest phase

conductor shall be installed in the duct bank.

2. Manholes and Handholes

a) Ground rod shall be installed close to wall and shall be set to a depth so
that 100 mm will extend above finished floor. The ground rod shall be
connected to grounding bar inside the manhole by bare copper
conductor. The bare copper conductor shall enter the manhole through
a waterproof sleeve in manhole wall. Size of the conductor shall be as
specified on the Contract Drawings and Documents.

b) Ground rods passing through concrete floor shall be protected with a

double wrapping of pressure-sensitive tape or heat-shrunk insulating
sleeve from 50 mm above to 150 mm below concrete. Floor opening
shall be sealed with waterproof, non shrunk grout.

3. Connections to Manhole Components

a) Exposed metal parts, such as inserts, cable racks, pulling irons, ladders,
and cable shields within each manhole or hand hole shall be connected
to ground bar inside manhole shall be connected to ground rod or
grounding conductor.

b) Connections shall be made with stranded hard drawn copper conductor.

The size of the conductor shall be as specified on the Contract Drawings
and Documents.

Rev 0 19 of 20 Contract No:

 SECTION 16060
GROUNDING AND BONDING

3.03 TESTING AND COMMISSIONING

A. General

1. The Contractor shall carry out all site tests in accordance with approved test
procedures, codes and standards as specified in par. 1.04. Ensure that the
grounding equipment/materials comply with the specifications and operational
requirements. All tests are subject to witnessing by the Royal Commission
representatives.

2. At least 4 weeks prior to schedule tests, the Contractor shall submit to the
Royal Commission an outline of the plan and procedures to be used in
performing the site inspection and site tests.

3. This outline shall include a brief description of the test equipment, connection
diagrams, proposed tests and procedures, test sheets, calculations, reference
drawings and minimum and maximum test and performance values, in
conformance with this specification and acceptability of the equipment and its
installation.

4. Upon completion of installation and prior to final acceptance, each component

of each system shall be tested to the complete satisfaction of the Royal
Commissions.

5. The Contractor shall provide all test instrumentation, equipment and

accessories necessary for demonstration and putting the equipment into
operation before commissioning. All testing equipment shall be calibrated by
approved authorities and calibration certificates shall be provided to Royal
Commission for their review and approval.

6. Upon completion of all field testing, the Contractor shall submit to the Royal
Commission 5 copies of a certified test reports attesting that each test has
been performed in accordance with the approved test procedures. The report
for each test shall include the name of the person in charge of the test and the
date of performance. All factory and field test reports shall be included in
Operation and Maintenance Manuals.

7. All the necessary safety precautions shall be taken during field testing, for the
test equipment as well as the persons.

END OF SECTION

Rev 0 20 of 20 Contract No: