Current through Register Vol. XLI, No. 24, June 14, 2024
Section 36-1-31 - Electrical Provisions - Shaft and/or Slope31.1. Power circuits and electric equipment shall be deenergized before work is done on such circuits and equipment, except when necessary for troubleshooting or testing.31.2. No electrical work shall be performed on electrical distribution circuits or equipment, except by a qualified person or by a person trained to perform electrical work and to maintain electrical equipment under the direct supervision of a qualified person. Disconnecting devices shall be locked out and suitably tagged by each person who performs such work, except that in cases where locking out is not possible, such devices shall be opened and suitably tagged by each person who installed them, or, if such persons are unavailable, by qualified persons authorized by the operator or his/her agent. 31.3. Electrical equipment shall be examined weekly, tested, and properly maintained by a qualified person to assure safe operating conditions. When a potentially dangerous condition is found on electric equipment, such equipment shall be removed from service until such condition is corrected. A record of such examination shall be kept and made available to an authorized representative of the Director and to the miners in such mine. 31.4. Surface transformers shall be elevated at least eight (8) feet above the ground or enclosed by a fence six (6) feet high, grounded if metal; shall be properly grounded; shall be installed so that they will not present a fire hazard; and shall be guarded by sufficient danger signs. The gate or door to the enclosure shall be kept locked at all times unless authorized persons are present.31.5. Electric conductors shall be sufficient in size and have adequate carrying capacity and be of such construction that a rise in temperature resulting from normal operation will not damage the insulating material. 31.6. Electrical connections or splices in electric conductors shall be mechanically and electrically efficient, and suitable connectors shall be used. All electrical connections or splices in electrical connections or splices in insulated wire shall be reinsulated at least to the same degree of protection as the remainder of the wire.31.7. Short circuit protection to protect all electric equipment and circuits against short circuits and overloads shall be provided by an automatic circuit breaker or other no less effective device approved by the Director. Three-phase motors on all electric equipment shall be provided with overload protection that will deenergize all three phases in the event that any phase is overloaded. 31.8. The booms and masts of equipment operated on the surface of any shaft or slope shall not be operated within ten (10) feet of an energized overhead powerline. Where the voltage of overhead powerlines is sixty-nine thousand (69,000) volts or more, the minimum distance from the boom or mast shall be as follows: Nominal power line voltage (in (1,000) volts) | Minimum distance (feet) |
69-114 | 12 |
115-229 | 15 |
230-344 | 20 |
345-499 | 25 |
500 or more | 35 |
31.9. During construction, electrical equipment employed below the collar or within twenty-five (25) feet of the return or exhaust of a slope or shaft during excavation shall be approved or permissible and shall be maintained in a permissible condition. 31.10. The insulation of all electric conductors employed below the collar of any slope and shaft during excavation shall be of the flame resistant type. 31.11. During the construction of shaft or slope only lamps and portable flood lights approved by MSHA shall be permitted below the collar of the shaft or slope.31.12. Metallic frames, casings, and other enclosures of electric equipment that can become "alive" through failure of insulation or by contact with energized parts shall be effectively grounded. 31.13. All power wires (except trailing cables on mobile equipment, specially designed cables conducting high-voltage power to underground rectifying equipment or transformers, or bare or insulated ground and return wires) shall be supported on well-insulated insulators and shall not contact combustible material, roof, or ribs. 31.14. Well-insulated insulators is interpreted to mean well-installed insulators. Insulated J-hooks may be used to suspend insulated power cables for temporary installation not exceeding six (6) months and for permanent installation of control cables such as may be used along belt conveyors.31.15. Power wires and cables shall be insulated adequately and fully protected. 31.16. Power wires and cables shall have insulation with a dielectric strength at least equal to the voltage of the circuit. 31.17. Each ungrounded, exposed power conductor that leads underground shall be equipped with suitable lightning arresters of approved type within one-hundred (100) feet of the point where the circuit enters the mine. Lightning arresters shall be connected to a low resistance grounding medium on the surface which shall be separated from neutral grounds by a distance of not less than twenty-five (25) feet.31.18. Short circuit protection for trailing cables shall be provided by an automatic circuit breaker or other no less effective device approved by the Director of adequate current-interrupting capacity in each ungrounded conductor. Disconnecting devices used to disconnect power from trailing cables shall be plainly marked and identified and such devices shall be equipped or designed in such a manner that it can be determined by visual observation that the power is disconnected and a suitable means to provide the ability to lock and tag. 31.19. Dry insulating platforms of rubber or other suitable nonconductive material shall be kept in place at each switchboard and at stationary machinery where shock hazards exist.