Timeline for Which breaker should trip with a ground fault with a subpanel?

5 events

when toggle format	what		by	license	comment
Jan 31, 2016 at 21:30	comment	added	Tester101		The OP specifically asked what would happen with a ground-fault on a circuit in the outbuilding "I am trying to conceptualize how a ground fault on a circuit in the outbuilding would trip a breaker and which would trip.". They also said they ran a 4 wire feeder to the outbuilding, so there is a grounding conductor to the panel.
Jan 31, 2016 at 20:32	comment	added	ArchonOSX		Hmm well if you have the 4 wire method there is a ground wire for fault current and if you have the 3 wire method the fault current goes back on the neutral. The ground would also have to be broken in your scenario for that to work or the bond screw was left out in a 3 wire setup, but that is why they eliminated the 3 wire method in favor of the 4 wire. Either way the ground is a poor conductor hence the need for a wire type ground conductor to facilitate the action of the overcorrect device.
Jan 31, 2016 at 19:50	comment	added	TFK		There is a ground running back to the main. So in this case the breaker in the main feeding to the sub would trip first.
Jan 31, 2016 at 19:42	history	edited	Harper - Reinstate Monica	CC BY-SA 3.0	better wrap-up
Jan 31, 2016 at 19:29	history	answered	Harper - Reinstate Monica	CC BY-SA 3.0