After switching off my kitchen lights, there is a somewhat loud "click" almost exactly 7 minutes later. Infinitely reproducible, with no other discernible symptoms, and it seems to be otherwise harmless. The house is new construction, only about a year old, and the sound has been happening from the start. I originally thought it might have been coming from one of the GFCI outlets, but the outlet works fine and after listening to it a hundred times I now think the sound is actually in the wall somewhat above the outlet.

I have found a few posts online (e.g. from a DIY forum) but the advice seems to always be, "replace the receptacle" or "don't worry about it." I am not worried about the sound, and honestly don't really even care to stop it, I just want to know (because of naturally scientific curiosity) what causes it.

  • 1
    What kind of lights - incandescent, fluorescent, halogen or LED? Feb 19, 2018 at 15:30
  • Fixtures are recessed cans with LED bulbs. 5 cans on the circuit. Feb 19, 2018 at 15:34
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    Does it happen if you only flip the lights on for a second or two? if so, is it still 7 minutes? I'm thinking something thermal cooling down...so if not given time to heat up, it might either not happen or take less time to happen.
    – Ecnerwal
    Feb 19, 2018 at 15:37
  • Agree regarding possible thermal issue. Could also be something specific to the bulbs. If the bulbs are standard 120V AC bulbs, try swapping temporarily for compact fluorescent or a different type of LED bulb if you have some around the house. If the bulbs are something different (e.g. low voltage with a transformer/rectifier somewhere) then you can't do that. Feb 19, 2018 at 15:42
  • Hmm, I just tried leaving them on for 15 seconds, no click. I hadn't thought of that but they typically are on for an extended period when they are on at all. Feb 19, 2018 at 15:50

1 Answer 1


Answering this myself since I have an answer and this has gotten quite a few views.

The answer is that the sound was thermal, but not anything dangerous. After much experimentation, I discovered that one of the cans warps ever so slightly when it gets hot and after a period of about 7 minutes this cools enough to "pop" back down as it contracts. It also doesn't happen until it hits a heat threshold that occurs after about 10 minutes. Less than 10 minutes of on time yields no pop.

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