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I have these LED can lights all across the house. On a few of them I occasionally hear a single click sound and I'm so curious to find out why it happens and if it's a safety issue. I caught it on video for you to witness.

  • In second 1 you hear me operate the light switch to turn off the lights.
  • In second 5 you hear the subtle click sound

I turned the volume of the video way up for you to hear the subtle click. If you can't hear the click, turn up your volume as well to amplify. The light switch sounds super loud in the video because I turned up the volume, but it's just a regular decora rocker switch that isn't loud at all in real life. The click sound a few seconds later is about 20% the volume of the switch, so that gives a good comparison. It sounds a little bit like the cracking of an ice cube when putting it in warm water.

For weeks I've been investigating 🕵🏼‍♂️ and now finally taking it to the community since I'm stuck 😄

From what I've read I'm fairly certain that it's some thermal action in the can light itself that comes from heating up and cooling down, hence the unpredictable timing. But what clicks in there? And why only in some?

Has anyone ever experienced something like that? What could be done? Is it a safety hazard that has to be addressed or can the clicking noise just be ignored? Any help appreciated!

A few things that might help the investigation:

  • The click only happens at most once per can usually a few seconds after turning the lights on or off

  • The click comes directly from the direction of the can lights (not from the switch or anything)

  • The click can happen quickly after (like 4 seconds as in the video) or a little later (like 45 - 60 seconds after operating the switch)

  • The click doesn't always happen per can light, but I would say in 60% of cases

  • The click only happens when the lights have been either on or off for at least 10 minutes. Like switching the light on and off quickly for testing doesn't make it click.

  • I believe in the video the click happens on the right two can lights, that's why it sounds a little bit light a click,click, although it's hard to tell

  • I think the more can lights are on a switch, the more predictable I get at least a few clicks. Like the kitchen with 8 can lights clicks almost every time, this bathroom with 5 can lights clicks most of the time, in a stair case with 4 can lights it sometimes happens without click, sometimes with. However some LED can lights never click at all, even if there's many on a single switch.

  • I'm in the US, so 120V and 15A circuits

  • The house is a new construction and the wiring has all been done end of 2021

  • I have installed these sonoff zb mini devices to control lights and fans remotely on a few unrelated switches (like the bathroom fan), but they happen to be on the same circuit. I can't say for sure now, but I think the click only started after the installation of the device. Important to note is that the LEDs that are clicking are not operated by such a smart device, they have the regular old switch. They just happen to be on the same circuit with the same breaker. My feeling tells me that only circuits that have such a sonoff zb mini device anywhere in the circuit make the click sound. That is supported by the fact that all the circuits that don't have a sonoff zb mini device anywhere installed also don't click. Or at least it's way more rare. I think I've heard it once or twice on circuits that haven't been touched. However, there is one circuit that has a switch with 6 LED can lights and also a zb mini elsewhere and none of those 6 LEDs ever click.

  • I've since disconnected the sonoff zb mini from one of the circuits for testing, but the clicking on 8 of the can lights on another switch within that circuit didn't go away. So I can't undo it through removing the sonoff zb mini.

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    Have you checked with the manufacturer? I think you'll get a lot of opinions here but nothing factual.
    – JACK
    Mar 13, 2022 at 13:25
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    likely mechanical; a snug metal on metal fit re-adjusting as it cools due to differing thermal expansion properties of two materials used in the fixture or mounting. It probably clicks when warming too, though that likely happens slower and thus more sporadically. It's not an electrical fitting as that would be too small to hear except up-close, as the leads and connections are tiny these days.
    – dandavis
    Mar 13, 2022 at 21:49
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    May not apply to you, but I had a very similar experience. I turned off the lights and then would hear a click a few seconds later. After a couple of days trying to track it down (it wasn't consistent), I finally found that it was my security cameras flipping into night vision mode and only when it was dark outside which was why it wasn't consistent. Dec 9, 2022 at 0:51
  • My bathroom LED fixture makes a funny click noise when I turn it off after it's been on a while, but not after short usage. The LED fixtures in the basement that replaced our old 6-foot fluorescent tubes do the same thing. I also assumed it's some thermal effect but stopped thinking about it since everything's worked fine for years. Feb 18, 2023 at 18:31

2 Answers 2

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You don't need to guess about safety.

That "heavy lifting" has been done for you.

Anything installed (at least, in North America) must be approved. NEC 110.3 and equivalent.

"Approved" means by an independent, 3rd party "Nationally Recognized Testing Lab" or NRTL. That list is curated by US OSHA but is widely recognized. The testing lab measures the equipment against the "UL White Book" safety standards for that equipment (e.g. UL 1598 for luminaires/lights).

Note the following common marks are not only not NRTLs, but very often faked: CE, CCC, RoHS and FCC. If you don't see an NRTL mark, and you didn't buy it from a bricks-and-mortar retailer inside the EU, count on the marks being fake.

So, it's as simple as to look at your lights, switches, and other equipment which has been installed. If you see an NRTL listing with a 6-9 digit file number, then you can presume the equipment to be safe and cross it off the "threat list".

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I’ve been in the electrical industry since 1977, and I’ve heard things like this all through the years. It is basically,I believe in the case of an LED, what you’re hearing is the LED driver switching on or off or a thermal cut out resetting. It could be intermittent due to the parts not being manufactured exactly to specs. I don’t think there’s anything to worry about.

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