Digital service entrance ground fault relay


The CMGF420 is a control-powered, UL 1053 listed service entrance relay for use in grounded systems. When combined with an N/O shunt trip breaker, it provides ground fault detection and interruption at the mains entrance of an electrical system. When a fault is detected, the output contacts will cause the connected shunt trip breaker to trip and interrupt power to the system.

The relay supports a pickup range of up to 1200 A when using a compatible current transformer. The CMGF420 supports current transformers with a 600:1 (60 - 1200 A trip range) or 1000:1 ratio (100 - 1200 A trip range).

After entering the proper current transformer ratio into the settings of the device, the value shown on the LCD screen will be the value read on the primary side of the current transformer.

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