CFR > Title 30 - Mineral Resources > CHAPTER I—MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR > SUBCHAPTER O—COAL MINE SAFETY AND HEALTH (parts 70 to 90) > PART 75—MANDATORY SAFETY STANDARDS—UNDERGROUND COAL MINES > SUBPART J—Underground Low- and Medium-Voltage Alternating Current Circuits (§75.900 to §75.907) > 75.900—Low- and medium-voltage circuits serving three-phase alternating current equipment; circuit breakers.

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

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.