Swimming Pool Light

[JEuriech]

I tend to find a lot of swimming pools with unsafe conditions. As a result, I usually do a limited inspection of swimming pools as a way of life.

I inspected a 1978 house a couple of days ago that had a swimming pool. The GFI outlet was missing from the sub-panel/timer box. There was only a large hole where the GFI used to be. Obviously a safety concern.

I turned the pool light on to see if it worked and walked over to the pool. The pool light was off. However, there was a large bubble coming up from the pool light to the surface. Another bubble followed about a foot behind and then another bubble. When the bubbles broke through the surface they were white smoke. I had smoke hanging over the end of the pool. I quickly turned the power off to the pool light.

What caused the smoke bubbles? If the light had shorted out, you would think the breaker would have tripped. Any guesses?

Jeff Euriech

Peoria, AZ

[Jim Katen]

There could have been an arc with enough resistance to prevent the breaker from tripping.

- Jim Katen, Oregon

[Rob Amaral]

Ground fault with no equipment ground connection back to the circuit's breaker? A corroded breaker (inside the breaker?)

[Rob Amaral]

In other words, it could be a 'ground fault' that can't clear itself' as it has no proper return path (to the utility transformer). It would sizzle itself 'clear' eventually (maybe) but still be a 'problem'. Sounds nasty.

[Brian G]

Somebody call Norm and tell him to drop by.

Brian G.

Norrrrmmmm!

[Chad Fabry]

Jim,

It would have been an arc with enough continuity to prevent the breaker from tripping.

[Norm]

I'm at a loss. Never have seen that before and don't have a clue. I will discuss this with my contemporaries down here in the hopes that someone will have a viable explaination. Where there's smoke there's fire or so they say. Is this a 120 Volt light or is there a step down transformer present?

NORM SAGE

[Erby]

Wires shorted out.

Breaker failed to trip.

Wire insulation burning in the conduit.

Heat causes expansion of the air.

Air pressure increases in conduit.

Heat rises.

Air forces its way thru the seal on the light fixture.

Smoke bubbles to the surface of the pool.

Bubble pops.

Smoke on the water.

Sometimes you just can't resist!

[JEuriech]

Norm,

It was a 120 volt light. No transformer present. The buyer asked me if I stuck my hand in the water to see what would happen? I told her that after I saw the smoke bubbles, I wasn't going to get anywhere close to electricity and water.

Jeff Euriech

Peoria, Arizona