The type GC-100 Ground Fault Protection System is suitable for use on equipment connected to a source having
200,000 RMS amperes or less available ground fault current.
The GC 100 relay contacts (internally connected to terminals 12 and 19) are rated as follows:
Inrush 50 amperes, Continuous 10 amperes
Break 10 amperes
Normal transient voltage surges are suppressed to a level that will not cause the GFR to nuisance trip. Under
extreme transient conditions, additional protection may be necessary. Contact your local Square D office for
assistance if repeated outage caused by transient line voltage surges is experienced.
The GC-100 relay has the following power requirements:
3 watts Typical
12 watts Typical
Note, however, that the switch or circuit breaker trip coil requires additional power from the control supply. The
control power transformer must have adequate size and regulation characteristics to trip the disconnect when the
line voltage drops to 55% of its normal value.
Restraint interlocking between relays:
Each Ground Fault Relay Restraint Output can drive up to eight restraint unit loads.
Total restraint unit loads may be calculated by adding the number of Restraint To Time Delay Inputs plus
twice the number of Lockout Restraint Inputs which the Restraint Output must drive.
i.e., Restraint To Time Delay Input
1 unit load
Lockout Restraint Input
2 unit loads
Each GFR Restraint To Time Delay and Lockout Restraint Input can receive signals from up to twenty
Restraint Output sources provided that no more than six of the sources can be energized simultaneously.
CAUTION INSTRUCTION AND NOTES
Do not ground terminal 15 or connect it to any terminal other than a number 16 or 17 terminal.
Note that terminals 18 and 19 are permanently internally connected.
All Ground Fault Relays using restraint interconnections must have a common ground connected to terminal 18 or
Once the GFR has tripped for any reason, it must be reset before the protected circuit breaker or switch can be
turned "on" and remain closed.
During installation, inspection or replacement, jumper from terminal X1, X3 to terminal X2, X4 on the Sensor to
prevent possible high voltage outputs. The jumper must be removed when all wiring is complete.
The Ground Fault Relay needs little maintenance due to its solid state control and sensing circuitry. The output relay
mounted on the top endwall should be inspected periodically along with the terminal connections for corrosion, pitting and
tightness. If the Ground Fault Relay fails to operate properly or is subjected to physical or electrical damage, it should be