30 CFR § 75.821
Testing, examination and maintenance.
(a) At least once every 7 days, a person qualified in accordance
with § 75.153 to perform electrical work on all circuits and
equipment must test and examine each unit of high-voltage longwall
equipment and circuits to determine that electrical protection,
equipment grounding, permissibility, cable insulation, and control
devices are being properly maintained to prevent fire, electrical
shock, ignition, or operational hazards from existing on the equipment.
Tests must include activating the ground-fault test circuit as required
by § 75.814(c).
(b) Each ground-wire monitor and associated circuits must be
examined and tested at least once each 30 days to verify proper
operation and that it will cause the corresponding circuit-interrupting
device to open.
(c) When examinations or tests of equipment reveal a fire,
electrical shock, ignition, or operational hazard, the equipment must
be removed from service immediately or repaired immediately.
(d) At the completion of examinations and tests required by this
section, the person who makes the examinations and tests must certify
by signature and date that they have been conducted. A record must be
made of any unsafe condition found and any corrective action taken.
Certifications and records must be kept for at least one year and must
be made available for inspection by authorized representatives of the
Secretary and representatives of miners.