30 CFR § 75.900 - Low- and medium-voltage circuits serving three-phase alternating current equipment; circuit breakers.

---
identifier: "/us/cfr/t30/s75.900"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "30 CFR § 75.900 - Low- and medium-voltage circuits serving three-phase alternating current equipment; circuit breakers."
title_number: 30
title_name: "Mineral Resources"
section_number: "75.900"
section_name: "Low- and medium-voltage circuits serving three-phase alternating current equipment; circuit breakers."
chapter_name: "MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR"
subchapter_number: "O"
subchapter_name: "COAL MINE SAFETY AND HEALTH"
part_number: "75"
part_name: "MANDATORY SAFETY STANDARDS—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, 813(h), 957."
regulatory_source: "35 FR 17890, Nov. 20, 1970, unless otherwise noted."
cfr_part: "75"
---


# 75.900 Low- and medium-voltage circuits serving three-phase alternating current equipment; circuit breakers.

****[Statutory Provisions]

Low- and medium-voltage power circuits serving three-phase alternating current equipment shall be protected by suitable circuit breakers of adequate interrupting capacity which are properly tested and maintained as prescribed by the Secretary. Such breakers shall be equipped with devices to provide protection against undervoltage, grounded phase, short circuit, and overcurrent.