SGF Junior

The SMC SGF-Jr Sensitive Ground Fault Relay is a basic ground fault relay that provides accurate sensitive ground fault protection.

It is used to protect electrical cables and equipment from phase to ground faults.  When the preset level of fault current and time delay are exceeded, the relay will initiate a trip action.  The SGF-Jr system uses a current transformer connected in a zero sequence or a ground return sensing method.


The SGF-Jr Relay is used for less critical 2300 to 4160 volt medium voltage applications where sensitive ground fault protection is necessary


  • Analog meters (optional)
  • High degree of nuisance trip immunity
  • Time delay tripping range 0 to 250 milliseconds
  • Selector switch operation
  • Accepts CT test winding
  • Remote 120 VAC test trip
  • Remote 120 VAC reset
  • Sensitive, accurate current measurement .125 to 3.0 amps
  • LED indication for power, CT fault and current fault
  • Failsafe design - Output relay coil is energized during non-fault conditions
  • Requires SMC high noise rejection CT’s
  • Enclosure standard DIN case
  • Mounts on panel or retrofits to other standard DIN Case relays
  • Uses quick disconnect terminal connectors