120 V Wet-Niche Light, Tripping GFCI, and a Splice in the Niche
A 1995 gunite pool with a single 120 V, 500 W incandescent wet-niche light. The light works, but its GFCI trips within a few seconds whenever the switch is turned on; the same GFCI protects the pump, and the pump runs fine on it. The deck junction box is a standard 4-inch steel box mounted on a fence post 5 ft from the pool wall and 10 inches above the deck, with the cover missing and the cord entering through a knockout with no strain relief. At the niche, the cord has been cut and spliced with two wire nuts wrapped in electrical tape, and the splice sits about 6 inches inside the niche mouth. The niche's bonding terminal has no conductor on it. The cord between the niche and the deck box measures about 3 ft. The homeowner says it is only 120 volts and it is on a GFCI, so it is safe.
1. List the defects and the hazard each one creates.
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The GFCI tripping only on the light circuit tells you the fault is in the luminaire, its cord, or the splice - a ground fault, not a shared-circuit problem, since the pump runs on the same device. The wire-nut splice 6 inches inside the niche is the most serious: that location is permanently wet, splices are not permitted there, and the connection is directly in the water path a bather's hand enters. The missing niche bond means the metal forming shell is not tied to the equipotential grid, so a fault can energize the shell and the water around it. The deck box is a standard steel box, not a listed pool deck junction box, and the missing cover and absent strain relief expose live terminations to weather and allow the cord to be pulled at the splice. The 3-ft cord is also a red flag: a wet-niche luminaire cord must be long enough - at least 4 ft from the shell - to bring the fixture onto the deck for service, so this cord was shortened.
2. How do you answer the homeowner's safety claim?
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Two misconceptions are stacked here. First, 120 V is not a low-voltage pool circuit; a wet-niche luminaire at 120 V is permitted only when it is a listed unit, GFCI-protected, correctly bonded, and installed with a listed deck box - the voltage by itself does not make it safe. Second, a GFCI is backup protection, not a license to operate a defective fixture. A GFCI trips because current is returning by an unintended path, which in a pool means through water, plaster, or a bather. Repeatedly resetting it, or replacing it with a larger device, defeats the only thing standing between a fault and a person in the water. The correct response is that the circuit should be left off and the fixture repaired or replaced before the pool is used; a GFCI that trips is doing its job.
3. What repair path do you recommend, and what should the buyer verify afterward?
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Recommend a licensed electrician and a qualified pool technician handle this as a unit replacement, not a repair. The luminaire and its cord should be replaced with a listed wet-niche unit having the correct cord length, the niche bonding terminal connected to the equipotential grid with a proper connector, and the standard steel box replaced with a listed pool deck junction box mounted per code with a cover and strain relief. All splices belong in that deck box, never in the niche. Afterward, verify by inspection and by test: GFCI trips and resets on its test button, no splice or damaged cord in the niche, bond conductor present and continuous, deck box secured and dry inside, and the fixture secure in the shell. Many inspectors also recommend converting to a listed 12 V system with a pool-listed transformer, which reduces the hazard if the fault recurs.