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 77—MANDATORY SAFETY STANDARDS, SURFACE COAL MINES AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES > SUBPART F—Electrical Equipment—General (§77.500 to §77.516) > 77.500—Electric power circuits and electric equipment; deenergization.

77.500—Electric power circuits and electric equipment; deenergization.

Power circuits and electric equipment shall be deenergized before work is done on such circuits and equipment, except when necessary for troubleshooting or testing.