30 C.F.R. § 77.902-2 Approved ground check systems not employing pilot check wires.
Title 30 - Mineral Resources
Ground check systems not employing pilot check wires shall be approved by the Secretary only after it has been determined that the system includes a fail safe design causing the circuit breaker to open when ground continuity is broken.
Title 30: Mineral Resources
PART 77—MANDATORY SAFETY STANDARDS, SURFACE COAL MINES AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES
Subpart J—Low- and Medium-Voltage Alternating Current Circuits
§ 77.902-2 Approved ground check systems not employing pilot check wires.
