30 C.F.R. § 77.803 Fail safe ground check circuits on high-voltage resistance grounded systems.
Title 30 - Mineral Resources
On and after September 30, 1971, all high-voltage, resistance grounded systems shall include a fail safe ground check circuit or other no less effective device approved by the Secretary to monitor continuously the grounding circuit to assure continuity. The fail safe ground check circuit shall cause the circuit breaker to open when either the ground or ground check wire is broken.
Title 30: Mineral Resources
PART 77—MANDATORY SAFETY STANDARDS, SURFACE COAL MINES AND SURFACE WORK AREAS OF UNDERGROUND COAL MINES
Subpart I—Surface High-Voltage Distribution
§ 77.803 Fail safe ground check circuits on high-voltage resistance grounded systems.
