Approved Capacity

DOE-HDBK-1092-98

7.5.3.2 APPROVED CAPACITY

Grounding cables shall accommodate the maximum fault current to which the cable or equipment

might be subjected.

7.5.3.3 GROUNDING CABLES AND HARDWARE

Personal protective grounding cables consist of appropriate lengths of suitable copper grounding

cable, with electrically and mechanically compatible ferrules and clamps at each end. In addition,

appropriate hotsticks are required for installing and removing the conductor-end clamps to the

conductors. Hotsticks are required for attaching ground-end clamps if the grounded system and the

worker are at different potentials. Cluster bars provide a low-resistance means of connecting the

ground-end clamps. Each of these components will be discussed in the following subsections.

7.5.3.4 GROUNDING CABLES

Most of the grounding cables in use today (and available for purchase) are actually manufactured for

another purpose-principally as welding cable. These extra-flexible copper cables with jackets are

manufactured according to appropriate ASTM standards for both cables and jackets, and can be

expected to perform satisfactorily as grounding cables.

7.5.3.4.1 STRANDING

There are several classes of flexible cable with various stranding in the sizes normally used for

grounding cables.

7.5.3.4.2 JACKETS

Welding cables are nominally insulated at 600 volts. When used as grounding cable, the insulation

or jacket serves primarily for mechanical protection of the conductor. The flexible elastomer or

thermoplastic jackets are manufactured, applied, and tested according to ASTM standards. Black,

red, and yellow jackets are usually neoprene rubber compounds, while clear jackets are ultraviolet-

inhibited polyvinyl chloride (PVC). All jackets should have the American Wire Gage (AWG) size

stamped or printed repeatedly along the length of the cable. The clear jacket allows easy visual

inspection of the conductor for strand breakage, but becomes stiff and hard to handle at low

temperatures. The clear jacket will split or shatter at very low temperatures.

7.5.3.4.3 FERRULES

Ferrules should be threaded-stud copper base compression type. Ferrules should have the filler

compound vent hole at the bottom of the cable so that employees can visually check that the cable

is fully inserted into the ferrule. Compound should be used with crimped ferrules. The ferrules should

be crimped with the ferrule manufacturer's recommended die. The press shall have enough pressure

to completely close the die. The area covering the inserted cable jacket should not be compressed.

Heat shrink or springs should be installed over a portion of the ferrule to minimize strand breakage

caused by bending. In all cases, the manufacturer's recommendations should be followed.

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