30 C.F.R. § 77.802 Protection of high-voltage circuits; neutral grounding resistors; disconnecting devices.
Title 30 - Mineral Resources
High-voltage circuits supplying portable or mobile equipment shall contain either a direct or derived neutral which shall be grounded through a suitable resistor at the source transformers, and a grounding circuit, originating at the grounded side of the grounding resistor, shall extend along with the power conductors and serve as a grounding conductor for the frames of all high-voltage equipment supplied power from that circuit, except that the Secretary or his authorized representative may permit other high-voltage circuits to feed stationary electrical equipment, if he finds that such exception will not pose a hazard to the miners. Disconnecting devices shall be installed and so equipped or designed in such a manner that it can be determined by visual observation that the power is disconnected.
Title 30: Mineral Resources
PART 77—MANDATORY SAFETY STANDARDS, SURFACE COAL MINES AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES
Subpart I—Surface High-Voltage Distribution
§ 77.802 Protection of high-voltage circuits; neutral grounding resistors; disconnecting devices.
