Operator safety from electrical shock depends to a large extent on the integrity of the grounding of the equipment when it is energized. It is vital, therefore to know if this grounding has been compromised; to do this a second auxiliary ground conductor is incorporated in the trailing cable to the mobile equipment.

The GCHK-100 monitors the loop resistance of the two grounds and trips when it exceeds a preset value.

Additionally, the relay will detect if the ground loop has become shorted or has opened. In the event of a ground connection failure and internal leakage within the mobile equipment, it is possible for the frame of the equipment to become live and present a shock hazard.

For added protection, the GCHK-100 detects high equipment frame voltages and quickly trips the relay. This feature will cause a trip twice as fast as the ground check and five times quicker for frame voltages exceeding 100V.

To service the special needs of the mining industry I-Gard has developed the GCHK-100 ground fault relay to improve safety for personnel and equipment in underground or above ground applications. Detection of ground faults is important where safety from electric shock and fire risk can occur and cause serious equipment and personnel hazards.

The relay is designed for use with resistance grounded systems up to 4160V but could be used with grounded systems in branch circuit applications where Load current is limited to 800A.