30 CFR § 77.802 - Protection of high-voltage circuits; neutral grounding resistors; disconnecting devices.
---
identifier: "/us/cfr/t30/s77.802"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "30 CFR § 77.802 - Protection of high-voltage circuits; neutral grounding resistors; disconnecting devices."
title_number: 30
title_name: "Mineral Resources"
section_number: "77.802"
section_name: "Protection of high-voltage circuits; neutral grounding resistors; disconnecting devices."
chapter_name: "MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR"
subchapter_number: "O"
subchapter_name: "COAL MINE SAFETY AND HEALTH"
part_number: "77"
part_name: "MANDATORY SAFETY STANDARDS, SURFACE COAL MINES AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES"
positive_law: false
currency: "2026-03-24"
last_updated: "2026-03-24"
format_version: "1.1.0"
generator: "[email protected]"
authority: "30 U.S.C. 811."
regulatory_source: "36 FR 9364, May 22, 1971, unless otherwise noted."
cfr_part: "77"
---
# 77.802 Protection of high-voltage circuits; neutral grounding resistors; disconnecting devices.
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.