Section 70-1123 - Direct current installation groundingThe following provisions shall apply only to direct-current electrical systems in anthracite coal mines:
(a) In a direct-current electrical system grounding shall consist in so connecting any part of an electrical system, including frames, to the earth that there shall be no difference of potential between them.(b) Only the negative side of the direct-current circuit shall be grounded.(c) Where track is used as a power conductor: (1) Both rails of primary track haulage shall be welded or bonded at every joint, and cross bonded at intervals of not more than two hundred feet. If the rails are paralleled by a feeder of like polarity, such paralleled feeder shall be bonded to the like track rails at intervals of not more than one thousand feet.(2) Act least one rail on secondary roads of a temporary nature shall be welded or bonded at every joint and cross bonded at not more than two hundred feet.(3) Track switches on entries shall be well bonded.1965, Nov. 10, P.L. 721, No. 346, art. XI, § 1123.