(a) Electric equipment must be permissible and maintained in a permissible condition when such equipment is located within 150 feet of pillar workings or longwall faces.

(b) Electric conductors and cables installed in or in by the last open crosscut or within 150 feet of pillar workings or longwall faces must be—

(1) Shielded high-voltage cables supplying power to permissible longwall equipment;

(2) Interconnecting conductors and cables of permissible longwall equipment;

(3) Conductors and cables of intrinsically safe circuits; and

(4) Cables and conductors supplying power to low- and medium-voltage permissible equipment.

(5) Shielded high-voltage cables supplying power to permissible continuous mining machines.