GFD Series Ungrounded Systems Alert

The GFD Series Ungrounded Systems Alert from the ATC Diversified Electronics division of Marsh Bellofram Corporation is intended for the use on ungrounded systems to detect and indicate the phase of the first ground fault condition. This enables corrective action to avoid the potential hazards resulting from a second ground fault. With nominal 3 phase line voltage applied, a flashing NORMAL green LED gives indication of a non-fault condition and integrity of the wire connection to the corresponding phase. A flashing red LED gives positive FAULT indication of either a phase-to-ground fault, or a lost connection to the corresponding phase.NOTE: Distributed capacitance to ground or equally loaded phases to ground will desensitize detection and will require lower phase-to-ground resistance to produce a FAULT indication.



  • For Use on Un-Grounded Systems
  • Detects & Indicates Phase of First Ground Fault
  • Horizontal and Vertical Mount Versions
  • Easy Installation in Conduit Knockout