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Electrical Conductors

30 CFR 56.12004 and 57.12004

30 CFR 75.513, 75.513-1, 77.503, and 77.503-1

 

56/57.12004

Electrical conductors shall be of a sufficient size and current-carrying capacity to ensure that a rise in temperature resulting from normal operations will not damage the insulating materials.  Electrical conductors exposed to mechanical damage shall be protected.

 

There is no MSHA policy for this standard.

 

75.513

All electric conductors shall be sufficient in size and have adequate current carrying capacity and be of such construction that a rise in temperature resulting from normal operation will not damage the insulating materials.

There is no MSHA policy for this standard.

 

75.513-1

An electric conductor is not of sufficient size to have adequate carrying capacity if it is smaller than is provided for in the National Electric Code, 1968.  In addition, equipment and trailing cables that are required to be permissible must meet the requirements of the appropriate schedules of the Bureau of Mines.

MSHA policy can be found here: 75.513-1

 

77.503

Electric conductors shall be sufficient in size and have adequate current carrying capacity and be of such construction that a rise in temperature resulting from normal operation will not damage the insulating materials.

MSHA policy can be found here: 77.503

 

77.503-1

Electric conductors shall be sufficient in size to meet the minimum current carrying capacity provided for in the National Electric Code, 1968.  All trailing cables shall meet the minimum requirements for ampacity provided in the standards of the Insulated Power Cable Engineers Association National Electric Manufacturers Association in effect when such cables are purchased.

There is no MSHA policy for this standard.

These standards apply to electrical conductors, their size, their capacity, their construction (coal), insulating materials, and whether they are protected from mechanical damage (metal and nonmetal).

 

Issues to Consider in Determining Compliance:

        Are conductors large enough so that they will not heat up and damage the insulating materials?

        Are conductors protected from mechanical damage such as vehicular traffic, chafing points on conveyor frames, motors, etc.?

»      If conductors are exposed to mechanical damage, are they protected with suitable conduit, bridging, outer jackets, slings, etc.?

 

Other issues covered by related standards:

        Are conductors insulated or bushed properly where they pass into or out of electrical compartments, splice boxes, or motor frames?

(56.12008, 57.12008, 75.515, and 77.505 - insulation and fittings for power wires and cables)