html{display:none} SEL-GFD Underground Ground Fault Detector | Schweitzer Engineering Laboratories


Underground Ground Fault Detector

The SEL-GFD provides the following features and benefits:

  • Ground fault detection by sensing the vector sum of the current flowing through a three-conductor cable.
  • Three reset options (secondary voltage, load current, or time) to meet various application needs.
  • Split-core sensor that installs on three-phase cables without opening the primary.
  • Large reflective red target display that is easy to see both at night and during the day.
  • Submersible, vinyl-coated sensing core.
  • Stainless steel hardware and UV-stabilized materials to ensure a long product life.

Thousands of SEL-GFDs in service today help customers around the world quickly locate ground faults.

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Industrial Sites—Apply the SEL-GFD over a three-phase cable bundle at ground potential in live-front switchgear to identify faults on circuits feeding mining equipment, medical facilities, and other industrial equipment. The vinyl-coated sensor core and potted circuit components provide an excellent seal against moisture and humidity in challenging industrial environments. The split-core sensor installs on three-phase cables without the need to open the primary or interrupt vital industrial operations.

Underground Cable at Substations—Apply the SEL-GFD to an underground cable distribution circuit feeder before the feeder leaves the substation to identify ground faults in the underground section of the circuit.

Low Load Current—Choose a secondary reset option to power and reset the SEL-GFD from secondary voltage (120–240 VacL-N) at a transformer. The SEL-GFD reset and powering options provide a wide range of compatibility across various applications, especially where feeders are lightly loaded or there is no load present.


The Firmware IDs for older versions of the firmware can typically be found in Appendix A of the instruction manual.