The C54 draw out ground monitor is for low, medium, and high voltage circuits to continuously monitor the grounding circuit to assure ground wire continuity. The ground wire from the cable being monitored passes thru a A2964 CT before being terminated to the switchgear case or to the optional inverse parallel Diode Assembly (C-2596). Therefore the line plug and receptacle must be isolated from the ground wire. A flexible ground strap must be connected between the plug and housing and switchgear unit enclosure. It must have the same current rating as the ground conductor. For wiring instructions see terminal connections diagram.
The C3000 Diode Assembly is provided for all applications. Whenever the Diode Assembly is reinstalled the Diode Assembly connections should be checked against drawings to prevent nuisance tripping.
Operation
Ground Loop Resistance Circuit – Monitors the grounding circuit. The ground monitor relay energizes if the combined pilot to ground wire resistance is less than 7.5 ohms and de-energizes if the combined resistance exceeds 50 ohms (20 ohms pickup for the shearer option).
Ground Monitor Relay – Special relay that cannot be energized by alternating current. If a pilot to ground fault exists, shorting out the diode at the machine, the ground monitor relay will re-energize and trip the power circuit breaker.