Using a fluorescent tube ceiling light after a leak
July 17, 2018 6:08 AM   Subscribe

Several days after a leak that came through a fluorescent tube light fitting, my mother's told me there's no problem with the light as she's turned it on and it was fine. I'm not happy this is safe.

Four days ago my mother's upstairs neighbours had a leak that resulted in water coming through her ceiling, including through the light fitting, which is a fluorescent tube.

The leak was fixed three days ago, and she's currently trying to sort out insurance details. In the meantime she just told me the light is fine as she turned it on and it worked and she's now happy it's safe. I'm not, but don't know if I'm being unreasonable given she's already tried it and it worked. This is for a UK house.

Should I stop worrying or should I be trying to convince her to stop using it and get it checked by an electrician? If she needs to stop using it, can I have details on the reasons as me saying so will not be enough.
posted by SometimeNextMonth to Home & Garden (4 answers total)
Best answer: As long as the fixture is on a circuit breaker, and there is not standing water in the lens, it should be perfectly fine. A fluorescent tube is low current and will hum along through all sorts of humidity, UL fixtures can take a surprising amount of abuse.
posted by nickggully at 6:14 AM on July 17, 2018 [1 favorite]

Best answer: Whether or not it is safe really depends on the design. Fluorescent lights have a ballast that lowers the current while increasing the voltage. It's not anything fancy - just a transformer, and they are pretty durable. Sometimes they are sealed pretty well. Other times, not so much. So, I'd be concerned about water getting in there, and possibly other contaminants in the event that there wasn't any cover on it.

That said, it is entirely possible that the ballast never even got wet, let alone had any water or debris infiltration. There's no way for us to know - even water in the fixture wouldn't necessarily imply the ballast got wet. It's much smaller than the fixture itself and usually tucked out of the way.

It wouldn't hurt to have an electrician check it out, but - if its working, I'd be surprised if there was any problem with it.
posted by Pogo_Fuzzybutt at 6:31 AM on July 17, 2018

Best answer: A fluorescent tube is low current

Sorry, that is irrelevant. The fixture is connected to the mains, and worst case a short would allow the full current through whatever is shorting the circuit, up to the limit set by the circuit breaker. With a short allowing a large (but not large enough for the breaker to trip) current to flow the shorting item will heat up, which rarely ends well. A bit of water doesn't have sufficient conductivity to cause such a short though. The bigger problem with water is that it does have sufficient conductivity to get mains voltage to the outside of a fixture, which will at least give you a nasty jolt if you touch it, and may, worst case, kill. But after a few days the water will have evaporated and the danger gone.

If the fixture is on the ceiling as I gather from the description so it's out of reach, and it starts OK, doesn't hum, smell or emit smoke worse than it did before the leakage, then I wouldn't hesitate to keep using it.

Fluorescent lights have a ballast that lowers the current while increasing the voltage.

A conventional fluorescent ballast is just a current limiter, reducing the voltage at the tube. An electronic 'ballast' does boost the voltage at the tube to start it (dispensing with a conventional starter that way), but once started the voltage gets lowered just as with a conventional ballast.
posted by Stoneshop at 7:06 AM on July 17, 2018

Response by poster: Thank you all, I feel a bit more reassured now. There is a circuit breaker and no one will be touching the light when it's on. I've checked and there were no strange noises, smells, smoke or anything ele and the light was behaving normally, so I won't worry too much.
posted by SometimeNextMonth at 8:55 AM on July 17, 2018

« Older Computer games to help develop maths fluency?   |   Hot Cleaning Tips Newer »
This thread is closed to new comments.