WiremanWireman · Pool light trips the GFCI: troubleshooting for electricians · 2023 NEC ·
Pool light trips the GFCI
Water in the fixture, a damaged cord, a wet junction box or a bad GFCI.
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How it works
Most underwater pool lights are wet-niche fixtures: the light sits in a niche (forming shell) in the pool wall with extra cord coiled behind it, so it can be lifted out to the deck for service. The cord runs through conduit to a junction box or transformer near the pool. The GFCI that protects the light is a life-safety device in the water. When it trips, the cause is almost always water inside the fixture or a damaged cord, not a bad GFCI.
Every question and answer in this guide. Tap “Step by step” to walk through it.
- Has anyone felt a shock or tingle in or near the pool?
- YesShock hazard in the water
- No, just trippingWhen does it trip?
- When the light turns onTest: Pull the fixture and inspect it
- Water or fog insideWater inside the fixture
- Cracked or damaged cordDamaged fixture cord
- Looks dry and goodTest: Insulation-test the cord and fixtureExpect: Hundreds of megohms or higher on both.
- Low on the fixture and cordWater inside the fixture
- Low on the circuit to the junction boxWater in the junction box or conduit
- Both highGFCI may be faulty
- Even with the light switched offAnother load on the same GFCI
- When the light turns onTest: Pull the fixture and inspect it