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

Universal Citation: OK Admin Code 460:15-1-28

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.

(1) The operator shall have on record at the mine site a weekly inspection record of low and medium voltage equipment. All high voltage equipment and switch gear shall be inspected and recorded in an approved record book monthly.

(2) All power circuits and electrical equipment shall be de-energized before working on circuits or equipment except when necessary for trouble shooting or testing.

(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:

(1) Trailing cables shall be flame resistant.

(2) Distribution centers supplying current to more than one (1) trailing cable shall be protected against connecting the wrong cable by chaining and marking.

(3) Only one (1) temporary splice may be made in any trailing cable-such trailing cable may only be used for the next twenty-four (24) hour period. No temporary splice shall be made in a trailing cable within twenty-five (25) feet of the face machine, except cable reel equipment. All splices shall be mechanically strong and well insulated.

(4) Permanent splices shall be mechanically strong, insulated and sealed to exclude moisture, vulcanized or treated to provide flame resistant qualities and good bonding to the outer jacket.

(5) Trailing cables shall be clamped to machines in a manner to protect strain on the electrical connections.

(6) Trailing cables shall be adequately protected to prevent damage by mobile equipment.

(7) Trailing cables shall be adequately grounded.

Disclaimer: These regulations may not be the most recent version. Oklahoma may have more current or accurate information. We make no warranties or guarantees about the accuracy, completeness, or adequacy of the information contained on this site or the information linked to on the state site. Please check official sources.
This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.