Oklahoma Administrative Code
Title 460 - Department of Mines
Chapter 15 - Underground Coal and Asphalt
Subchapter 1 - General Standards
Section 460:15-1-28 - Electrical boxes, equipment and machinery
Current through Vol. 41, No. 13, March 15, 2024
(a) All junction or distribution boxes, handheld or moveable equipment and all face machinery used inby the last open crosscut shall be permissible and shall have affixed to it the permissible plate issued by the Bureau of Mines. The operator shall maintain the equipment in a permissible condition.
(b) All electric conductors shall be of adequate size to carry its intended load without damaging the installation as set forth by the National Electrical Code.
(c) Electrical connections or splices in insulated wire shall be efficient, suitable and have at least the same degree of protection as the remainder of the wire.
(d) Cables shall enter metal frames of motors, boxes and electrical compartments only through proper fittings. Wires passing through metal frames shall have substantial insulated bushings.
(e) All power cables, except trailing cables on mobile equipment, shall be supported on insulated hangers and shall not contact combustible materials, roof, or ribs.
(f) Communication wires and cables shall be insulated and supported on insulated hangers and separated so that they cannot be energized inadvertently.
(g) Automatic circuit breakers or fuses or the correct type and capacity shall be installed to protect electrical equipment from short circuits and overloads.
(h) Main power circuits disconnecting switches shall be installed underground within five hundred (500) feet of the bottom of the shafts and boreholes through which main power circuits enter the underground area of the mine, and within five hundred (500) feet where the main power enters the underground mine.
(i) All underground power cables and communication wires shall be equipped with lightning arresters.
(j) Circuit breakers and disconnecting devices shall be properly marked for identification.
(k) All underground branch circuits shall be equipped with an approved ground monitor.
(l) The following shall apply to trailing cables: