Gfci Breaker

[not_a_spa_tech]

I have read that a GFCI breaker in the outside disconnect is not the best idea due to false trips. It has to handle overcurrent as well as ground faults and can quickly go out of calibration. The best way is to install a 50 amp breaker in the house panel and a GFCI/ disconnect (not a circuit breaker) in the outside box. Has anyone heard of this and what are your thoughts? Do you have problems with a GFCI breaker false tripping?

Thanks

[mrfixit]

I am not an electrician, but it seems to me that if you are going to get a ground fault or overdraw it is just as likely if the breaker is in the house as outside. My guess is if the wiring and breaker are sized correctly, and the wiring is done properly, you will have neither of these problems.

[Dnepr Dave]

I'm pretty sure that a GFCI breaker in the outside disconnect is required by code. The owners manual for my spa shows it wired that way.

Dave

[hot_water]

The GFI isn't required by code to be in the disconnect, at least not in my area.

You are better off with it in the outside box, though. The GFCI device trip if you have a 5 millimp (or more) imbalance betwen the line and its return. If there is a ground fault, the device "notices" that the current going in is NOT equal to the current coming out, and figures that ithe differential must be going somewhere it's not supposed to... and it trips.

If you put your GFCI in the main panel, remember that it's AC, and depending on your spa you could well be drawing 30, 40, or even 48 amps (for a spa with a 60 A breaker). Compared to these big numbers, 5 milliamps is miniscule. With that long wire run of AC from your spa disconnect back to the main panel... it's much more likely that you'll inductively couple 5 milliamps into the ground wire, the white wire, or even the conduit (if metal conduit). Bingo, nuisance trip!

So, you're better off putting your GFI in the disconnect box. That way, you get the same protection but are less likely to get a nuisance trip, since the wire run is comparatively short. Doesn't men you're guaranteed not to get nuisance tripping... but it helps your chances.

[Mikey_in_NY]

You're correct - in my area the GFI can be either in the outside disconnect OR in the main service panel. Before I purchased my hot tub I asked dealers and electricians about this, they all said it doesn't matter which location you use, but maybe they weren't aware of the differential issue hotwater refers to. FYI I have a 60A GFI inside the service box, with a simple disconnect outside.