It would be GFCI protected but there are some circuits that may require GFCI protection in the branch circuit not the panel feeder.
But do you happen to know the reason for that requirement? Or have a guess? I can't think of why it would be that way.I don't have the book in front of me but if I remember correctly certain pool equipment requires the protection in the branch circuit.
It would be GFCI protected but there are some circuits that may require GFCI protection in the branch circuit not the panel feeder.
If the GFCI breaker in the feeder panel is a 2-pole with a load neutral output, it's possible that some leakage current from a 120V branch circuit on one phase could be effectively cancelled at the GFCI sense coil by leakage current in a branch circuit on the other phase . For example, if there's a ground fault on each phase with identical impedances, then there would be no net common-mode current on the L1, L2, N conductors that pass through the toroidal transformer of the GFCI and so it wouldn't trip. That's because the L1 and L2 voltages are 180 degrees apart and therefore the leakage currents from the two ground fault impedances will be 180 degrees apart, and so their magnetic fields will cancel at the toroid.I wasn’t aware of this. Do you know the reasoning behind this? I can’t think of why gfci protection in the branch is ever safer than the feeder if they are the same leakage current levels being used.
I'd buy that vowel. Possibly a stretch as you mentioned, but it's at least reasonable enough for me for a possible reason for why. Thank you.If the GFCI breaker in the feeder panel is a 2-pole with a load neutral output, it's possible that some leakage current from a 120V branch circuit on one phase could be effectively cancelled at the GFCI sense coil by leakage current in a branch circuit on the other phase . For example, if there's a ground fault on each phase with identical impedances, then there would be no net common-mode current on the L1, L2, N conductors that pass through the toroidal transformer of the GFCI and so it wouldn't trip. That's because the L1 and L2 voltages are 180 degrees apart and therefore the leakage currents from the two ground fault impedances will be 180 degrees apart, and so their magnetic fields will cancel at the toroid.
Obviously, a MWBC fed by a 2-pole breaker could have this same issue. But I think it's unlikely this issue would be significant in real life circumstances.
But do you happen to know the reason for that requirement? Or have a guess? I can't think of why it would be that way.