Pool light tripping GFCI breaker

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Chris J

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Does a GFCI circuit breaker trip from "only" a burned-out pool bulb? Or is the breaker-tripping a definite sign of a more serious ground-fault issue?

Our in-ground pool main light worked for years. It burned out once and I replaced it successfully, worked for about 1 more year. We let it sit that way for a few years.

Now, turning on the switch for the main light, the 15A GE THQL-CFCI circuit breaker trips immediately (the main light does not flicker or respond). I believe the breaker works fine, there is continuity when ON and open when OFF. Also the spa light works fine, on the same breaker. When the main light switch is turned on and the breaker trips, of course the spa light does not turn on.

I have checked inside the pool power panel, and inside the American Products junction box for the main light -- found no obvious issues (opens or shorts). Also no issues with the other pool equipment.

I am debating whether to buy and replace another bulb, or to call an electrician to troubleshoot an actual fault in the circuit.

Separately I am wondering if this is a good opportunity to switch to an LED light in that same fixture.

Thanks in advance for any suggestions!
 

Reach4

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Does your breaker look like this with terminals for both the hot and neutral?

Open (turn off) the breaker. I would remove both the hot and neutral wires from the breaker, and check the resistance between the loose neutral and a green/bare ground.

There should be well over 100,000 ohms (100 kΩ]). I expect you will find the resistance to be much lower than that.

I suspect you may have gotten moisture in the housing as you changed bulbs. Or a wire insulation could have been penetrated.

Is this fixture under water?
 

jadnashua

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Unless the GFCI is defective, what it is looking for is that the power going out on the hot lead = the power coming back on the neutral. People get confused because they equate neutral with ground...the ground conductor should NEVER have power on it. The GFCI compares the power going in/out and if it's off by >=0.005A (5ma), it trips. The safety ground connection is there to help ensure the breaker trips if there's a short, but doesn't carry current when in a properly working system.

So, there's likely a connection from the hot lead that is siphoning off some power, causing the GFCI to trip. It doesn't take much...could just be a little corrosion, which would not be unusual in a pool fixture as it ages. That 'leak' could be anywhere beyond the switch that turns that branch on...IOW, it might not be in the lamp fixture, but the wiring going to it, or even the switch itself.
 

WorthFlorida

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I'm not familiar with this breaker, it there an indication that the GFCI tripped and not the breaker itself due to overload?

What type of pool light? Line voltage or low voltage (12v). Low voltage lights use a transformer to drop the voltage. Unless the transformer went bad, the GFCI will not trip due to shorts on the low voltage side, however, the breaker may trip.

My first thoughts is moisture as Reach suggest. Moisture that can accumulate can cause a GFCI to trip. I had one outside outlet where wind driven rain would get inside of it and trip the GFCI without a load.
 
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