Issue:
Is it OK to use a Powerpact or Masterpact breaker with ground fault trip unit on an ungrounded delta system? Because the system is ungrounded will using a GFI trip unit cause a problem?
Product Line:
Circuit Breakers
Resolution:
There are no negatives (except cost) to applying a Powerpact or Masterpact with integral ground fault protection on an ungrounded delta system. Because the system is ungrounded, a phase to ground contact will not result in current flow to ground and the breaker will not respond. If another phase also had a ground fault, there would be a phase to phase fault through ground which the breaker would respond to as a short circuit if the current was high enough.
The NEC requirements in articles 210.13 and 230.95 are for ground fault protection on solidly grounded WYE systems with 150 V or more to ground, and they say nothing about ungrounded. So our recommendation is to not use breakers with LSIG trip units on ungrounded systems.
Is it OK to use a Powerpact or Masterpact breaker with ground fault trip unit on an ungrounded delta system? Because the system is ungrounded will using a GFI trip unit cause a problem?
Product Line:
Circuit Breakers
Resolution:
There are no negatives (except cost) to applying a Powerpact or Masterpact with integral ground fault protection on an ungrounded delta system. Because the system is ungrounded, a phase to ground contact will not result in current flow to ground and the breaker will not respond. If another phase also had a ground fault, there would be a phase to phase fault through ground which the breaker would respond to as a short circuit if the current was high enough.
The NEC requirements in articles 210.13 and 230.95 are for ground fault protection on solidly grounded WYE systems with 150 V or more to ground, and they say nothing about ungrounded. So our recommendation is to not use breakers with LSIG trip units on ungrounded systems.
Released for:Schneider Electric USA
