---
kind: "section"
citation: "30 C.F.R. § 75.802"
title: "30"
number: "75.802"
heading: "Protection of high-voltage circuits extending underground."
url: "https://uscodex.org/cfr/30/75.802"
---

# §75.802. Protection of high-voltage circuits extending underground.

- (a) Except as provided in [paragraph (b)](#b) of this section, high-voltage circuits extending underground and supplying portable, mobile, or, stationary high-voltage 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.
- (b) Notwithstanding the requirements of [paragraph (a)](#a) of this section, the Secretary or his authorized representative may permit ungrounded high-voltage circuits to be extended underground to feed stationary electric equipment if:
  - (1) Such circuits are either steel armored or installed in grounded, rigid steel conduit throughout their entire length; or,
  - (2) The voltage of such circuits is nominally 2,400 volts or less phase-to-phase and the cables used in such circuits are equipped with metallic shields around each power conductor, and contain one or more ground conductors having a total cross sectional area of not less than one-half the power conductor; and,
  - (3) Upon a finding by the Secretary or his authorized representative that the use of the circuits described in [paragraphs (b)](#b) (1) and (2) of this section does not pose a hazard to the miners.
- (c) Within 100 feet of the point on the surface where high-voltage circuits enter the underground portion of the mine, 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, except that the Secretary or his authorized representative may permit such devices to be installed at a greater distance from such area of the mine if he determines, based on existing physical conditions, that such installation will be more accessible at a greater distance and will not pose any hazard to the miners.

## Notes

### Amendments

[38 FR 4975, Feb. 23, 1973]

### Authority

Authority: 30 U.S.C. 811, 813(h), 957.

### Source

Source: 35 FR 17890, Nov. 20, 1970, unless otherwise noted.

### Amendments

[38 FR 4975, Feb. 23, 1973]