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 H—Grounding (§75.700 to §75.706) > 75.706—Deenergized underground power circuits; idle days—idle shifts.

75.706—Deenergized underground power circuits; idle days—idle shifts.

When not in use, power circuits underground shall be deenergized on idle days and idle shifts, except that rectifiers and transformers may remain energized.