background-waves

Ground-Fault Relays

Ground-Fault Relays
Ground-fault relays help protect people from injuries and prevent damage to electrical equipment. Littelfuse produces relays for grounded and ungrounded systems. The units work by detecting slight deviations in current, voltage, resistance, or temperature. When conditions for a ground fault exist, our relays trigger alarms or trip circuit breakers.
  • Alternating current supply voltage ratings from 120 V ac to 600 V ac
  • Operate at between 50 Hz and 60 Hz
  • Ground fault trip settings as low as 5 mA
  • Meet CSA standards
  • UL Listed
  • Available with normally open (Form A), normally closed (Form B), or combination normally open–normally closed (Form C) contacts
  • Fail safe/Non-fail safe contact operations
  • Automatic reset versions available
  • Optional or standard conformal coatings on internal circuits to protect against corrosion

Ground-Fault Relays Parts

FiltersFilters

Ground-Fault Relays Resources

Ground-Fault Relays Information Center

The primary purpose of grounding electrical systems is to provide protection against electrical faults. However, this was not common practice until the 1970’s. Until then, most commercial and industrial systems were ungrounded.

Although ungrounded systems do not cause significant damage during the first ground fault, the numerous disadvantages associated with ground faults resulted in a change to the grounding philosophy. There are other advantages for a grounded system, such as reduction of shock hazards and protection against lightning. Electrical faults can be divided into two categories: phase-to-phase faults and ground faults.

Studies have shown that 98% of all electrical faults are ground faults (Source: Woodham, Jack, P.E. The Basics of Grounding Systems). While fuses can protect against phase-to-phase faults, additional protection, such as protection relays, are typically required to protect against ground faults.