16060- grounding & bonding

8/6/2019 16060- Grounding & Bonding

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SPECIFICATIONS CONT. No.(1)

SECTION 16060

GROUNDING AND BONDING

PART - 1 GENERAL

1.1 DESCRIPTION

A. This Section specifies furnishing, installing, connecting and testing of a compelte

grounding and bonding system.

B. Related Work Specified Elsewhere:

1. Section 16050, General Provisions , basic material, methods and requirements

for electrical works

1.2 QUALITY ASSURANCE

A. This installation shall comply in all respects with the General Requirements for

Grounding and Bonding of Electrical Installations as set out in Article 250 of

NEC 70 NFPA and this specification.

B. Reference should be made to IEEE "Recommended Practice for Grounding of

Industrial and Commercial Power Systems" published by I.E.E.E., Inc. for

clarifiction, intent and guidance in executing the work. Also reference should be

made to SCECO Specificaion No. SES-P-108.08 -GROUNDING.

1.3 SUBMITTALS

A. Shop Drawings and Manufacturer's Literature:

B. Submit three copies of certified test report stating that equipment grounding system's

resistance measures a maximum of 5 ohms to ground.

PART - 2 PRODUCTS

2.1 GENERAL

All goods and products covered by these specifications shall be preferably, whenavailable, from an in-kingdom manufacturer approved by the Owner and conforming

with the requirements of specifications. In case it is an imported products the

manufacturer must have an agent in the kingdom. and shall have all required spare parts

in stock. procurement of all goods and products must be approved by the Owner.

A. A complete grounding system shall be provided as shown on the drawings and as

specified. The system shall satisfy all related codes and requirements.

B. System Ground (Neutral Ground): The neutral terminal of the site distribution

transformer shall be grounded. A set of grounding rods, loop interconnected with each

other, shall be connected with a cable a minimum of 500mm below ground to the

neutral terminal of the transformer. The rods shall be located a minimum of 3 metersfrom each other or any other electrode and shall be loop interconnected with each other

by copper conductor brazed, thermit welded or high pressure clamped with a bronze

Ministry of Higher Education 57838975.DOC - 1

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ground rod clamp designed expressly for the purpose to each rod below grade. The

system ground resistance shall be 5 ohms.

C. Equipment Control: The equipment ground systems shall be designed so that all

metallic structures, enclosures, raceways, junction boxes, outlet boxes, cabinets,

machine frames, portable equipment and other conductive items in close proximity withelectrical circuits operate continuously at ground potential and provide a low

impedance path for possible ground fault currents. The equipment ground resistance

shall be 5 ohms. If the resistance value of 5 ohms cannot be obtained , more ground

rods shall be provided to achieve 5 ohms or less. The Contractor will submit alternate

methods to achieve the required result for review by the Owner.

D. The system ground and the equipment ground shall be connected to the common

ground bus.

2.2 GROUND RODS

A. Ground rods shall be of bonded copper or copper-clad steel not less than 15 mm (5/8")in diameter; 3m (10 ft) long, driven full length into the earth. The copper-clad steel

ground rod shall be manufactured by a fusion-weld process resulting in an electrolytic

copper sheath homogeneously welded to an inner steel core. The thickness of the

copper sheath shall be approximately 10% of the overall rod diameter. Copper

electroplated steel is not acceptable.

2.3 GROUND BUS

A. Ground bus shall be furnished on all switchgear, panels and motor control centers and

shall be interconnected as shown in the grounding and bonding layout drawings.

2.4 CONNECTORS

The Contractor shall determine the number and size of pressure connectors to be

provided on all equipment grounding bars required for the termination of equipment

grounding conductors. In addition to the active circuits, provide pressure connectors for

all three-phase spares and spaces on switchgears.

2.5 JUMPERS

Each electrical expansion fitting shall be provided with an external copper bonding

jumper secured by approved grounding straps on each end of the fitting. Jumpers shall

be tin plated copper braided flexible suitable for the required use.

2.6 GROUNDING ELECTRODE CONDUCTOR

The grounding electrode conductor shall be of copper. The material selected shall be

resistant to any corrosive condition existing at the installation and shall be suitably

protected against corrosion. The conductor shall be solid or stranded and shall be

installed in one continuous Length without a splice or joint.

2.7 TYPE OF EQUIPMENT GROUNDING CONDUCTORS

The equipment grounding conductor run with or enclosing the circuit conductors shall

be one or more or a combination of the following: (1) a copper conductor. Thisconductor shall be solid or stranded; insualted with green PVC covered, or bare; and in

the form of a wire or a busbar of any shape; (2) rigid metal conduit; (3) intermediate




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metal conduit; (4) electrical metallic tubing; (5) flexible metal conduit approved for the

purpose and installed with fittings approved for the purpose; (6) armor of Type AC

cable; (7) the sheath of ineral-insulated metal- sheathed cable; (8) cable trays as

permitted in the code for grounding purposes. Exception No. 1: Flexible metal conduit

and flexible metallic tubing shall be permitted for grounding if all the followingconditions are met:

A. The total length in any ground return path does not exceed 1.8 m

B. The circuit conductors contained therein are protected by over current devices rated at

20 amperes or less.

C. The conduit or tubing is terminated in fittings approved for the purpose. The above is

an extract from NEC 70 NFPA.

2.8 SIZE OF GROUNDING ELECTRODE CONDUCTOR FOR AC SYSTEMS

LINE CONDUCTOR SIZE

sq-mm

GROUND CONDUCTOR SIZE

sq-mm

1.5

2.5

4

6

10

16

25

35

50

70

95120

150

185

240

300

400

1.5

2.5

4

6

10

16

25

16

25

35

5070

70

95

120

150

185

2.9 MINIMUM SIZE OF BONDING CONDUCTORS FOR. GROUNDING

RACEWAY AND EQUIPMENT

Rating or Setting of Automatic

Overcurrent Device in Circuit Ahead ofEquipment (Amperes)

Size

Copper Wire in mm

15

20

30

40

60

100

200

500

600

600

2.5

4

6

6

6

10

16

25

35

35




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800

1,000

1,200

1,600

2,000

2,500

50

70

95

120

150

185

2.10 GROUND-FAULT PROTECTION OF EQUIPMENT

Ground-fault protection of equipment shall be provided for solidly grounded wye

electrical services of more than 150 volts to ground, but not exceeding 600 volts phase-

to-phase for each service disconnecting means.

2.11 TEST

A. The completed equipment grounding system shall be subjected to a meggered test ateach service disconnect enclosure ground bar to insure that the ground resistance,

without chemical treatment or other artificial means, does not exceed five (5) ohms.

Certified test reports of the ground resistance shall be submitted for review by the

Owner.

PART - 3 EXECUTION

3.1 GENERAL

A. Except as may be described in Part 2 of this Section, refer to the applicable provisions

of Section (16050)& (02590) and the other sections of specifications, Division16.

END OF SECTION



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