30 CFR § 75.830
Splicing and repair of trailing cables.
(a) Splices and repairs.
(1) Splicing means the mechanical joining of one or more severed conductors in a single length of a cable including the replacement of: Insulation, semi-conductive tape, metallic shielding, and the outer jacket(s).
(2) Repair means to fix damage to any component of the cable other than the conductor.
(3) Splices and repairs to high-voltage trailing cables must be made:
(i) Only by a qualified person trained in the proper methods of splicing and repairing high-voltage trailing cables;
(ii) In a workman-like manner;
(iii) In accordance with §75.810; and
(iv) Using only MSHA-approved high-voltage kits that include instructions for outer-jacket repairs and splices.
(b) Splicing limitations.
(1) Splicing of the high-voltage trailing cable within 35 feet of the continuous mining machine is prohibited.
(2) Only four (4) splices will be allowed at any one time for the portion of the trailing cable that extends from the continuous miner outby for a distance of 300 feet.