Assistance needed...thanks in advance

The scenario: pool light works intermittently. What makes this odd, is this is since i had replaced last week the entire light fixture, bulb, and cable. whats left, am thinking? Was considering transformer, but then it wouldn't work at all, would it? So i switch it on first time, it lasts 10 min approx. then goes out. I turn off, then back on in like 5 works for about 5 min this time, and so on. Called the company that installed, they say must be a bad transformer. They tested the transformer initially upon starting the light diagnosis a week ago, and it had good voltage to it.

To make this episode worse, when installing new cable the moved or cracked the conduit behind the light niche, so had to have $2100 worth of work done to replace. So in sum, would seem to have new niche, light fixture, cable run. Does transformer go bad intermittently due to heat? I estimate it to be approx 25 yrs old.

Many thanks!


Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
Bedford, TX

Yes, transformers can go bad due to heat and have intermittent operation. It would not be the first thing I would think of, but it can happen. A pretty simple thing to test for.

Turn on light and measure the output of the transformer, should be some low voltage AC.. Wait until the light goes out and re-measure the transformer's output. It should be zero volts, if the transformer is the problem.

Jim R.