gfci question

[markf]

I have a pool house which holds the filter, pump, heater etc., which has a small sub panel, with two 20 amp breakers. These breakers are GFCI. The pump is on one circuit and everything else is on the other. The weird part is that when the pump starts up, the other breaker trips off, not the one with the pump.

There is an exterior gfci outlet, wired to the breaker that trips. It may be coincidence, but the problem seems to have started since I started using this outlet. It seems to me the gfci outlet is redundant, so could it be the cause of my problems? Should I replace it with a standard outlet.

Any thoughts?

Mark F

[sawduster]

I believe you are right and that could very well be the problem. The second GFCI in that line is redundant, and may be the problem.

[Ruffnek]

Triplefreak, pick up the white courtesy phone, please.

[TDHofstetter]

OK... a GFCI circuit trips when... it measures exactly how much current is flowing through the hot wire outbound, on its way to the device under power. It also measures exactly how much current is flowing through the neutral wire inbound, on its return trip to the panel. If those two currents aren't exactly the same, it assumes that some of the outbound current is going someplace else - to ground - whether through a person or a blade of grass or a locomotive. It doesn't care if the hot is carrying more current than the neutral or the other way around - it looks only for a mismatch.

So... this GFCI breaker that's tripping is either seeing more current on its hot wire than can be accounted for, or else it's seeing more current on its neutral wire than can be accounted for.

What are you using that other outlet for?

I've got a feeling that the pump's neutral is wired to the other GFCI outlet's neutral wire instead of to its own (or they're possibly wired together).

[dicklaxt]

Agreed they are on a common neutral and should not be,,,thats my thought anyway.

dick

[markf]

May 7, 2010 10:49:28 GMT -6 TDHofstetter said:

What are you using that other outlet for?

The outlet currently has an automatic pool cover plugged into it. This consists of a motor, a power indicator light and a forward and reverse switch. Currently it connected with an extension cord, but I will hard wire this after getting some wire fished through the right places.

I will replace the gfci outlet with a standard outlet tonight and see if that fixes it. If not I'll pull the cover off the subpanel and see what that looks like.

Mark F

[dicklaxt]

Teplace with regular only for testing only and then be extra careful, GFCI are required in wet locations.

dick

[Ruffnek]

May 7, 2010 16:07:52 GMT -6 dicklaxt said:

Teplace with regular only for testing only and then be extra careful, GFCI are required in wet locations.
dick

If the breaker is GFCI, everything on that circuit is GFCI protected. No need for a GFCI outlet.

[Leo Voisine]

When I wired my garage shop I had the choice to use GFI breakers or to use GFI recepticals. I used GFI breakers. According to NEC you do not need both, but you do need one.

[markf]

It was my understanding that if you had more than one gfci on a circuit they would not function properly.

Either way I tested the gfci outlet with one of those outlet checkers and it showed an open ground. I replaced it with a standard outlet and it still showed an open ground. I traced it back through several junction boxes and light fixtures and found the disconnected ground. I fixed that, but it did not fix the original problem of the breaker tripping. After some more investigating I found if I disconnected the part of the circuit that goes underground to a pool light, the breaker no longer tripped. I left that disconnected and went to bed since it was 12:30. I was glad I at least found the cause of the problem.

I know Cajun would have continued, but I like to get 6 hours of sleep.

Hopefully the installer of the automatic pool cover didn't cut the buried cable, but I'll see what I can find out on that tomorrow.

Mark F

[TDHofstetter]

Na, "stacked" GFCIs work fine - they're just wasted. I prefer to keep 'em out of the box, so there's at least one visible at the point of use; that saves reset journeys to the breaker box when one trips, and "proof" trips when somebody asks.

As ya get older, ya try & eliminate as many forays up & down stairs as ya can.

[triplefreak]

Check the wire size for the entire circuit. My money says it's undersized somewhere. It should all be 12 AWG.

[markf]

Problem Resolved!!!!!

In the concrete pool deck there is a water tight junction box which connects to a pool light. It looks like the water tight box was not pressure washer proof and got wet when the pool cover installer was cleaning up with the pressure washer. I cleaned up and dried up the box with a shop vac and replaced the rubber gasket and redid the connections with new wire nuts. Everything seems to be working properly now. Thanks everyone for your help.

TF: I check the wire gague, but I am pretty sure it was 12 gague to the subpanel; two hots, a neutral and a ground.

Mark F

[triplefreak]

Hey, I gave it a shot. ;D