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Overhead light was flickering. Opened it up and the old LED bulb in there was hot to the touch-- something I've never experienced with LED bulbs. This is a pretty old original fixture. Is there something wrong with the wiring/socket, or is this how an LED bulb goes bad?

The old bulb that got hot is the third photo-- the bulb with fins. The one currently installed I put in to test but don't want to mess around with it too much if it could be faulty wiring.

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  • 22
    I can't tell if yours is one, but a lot of LED bulbs say "not for use in fully enclosed fixtures" or similar. They are prone to overheating when there's nowhere for the heat to go. They don't get nearly as hot as incandescents, but they also can't tolerate nearly as much heat as incandescents can. Sep 8, 2023 at 4:04
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    The bulb has 120V written on it, while the socket has 250V written on it. What voltage is your supply?
    – Aaron F
    Sep 8, 2023 at 13:15
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    @AaronF That's just the maximum rating for the socket.
    – Herohtar
    Sep 8, 2023 at 14:41
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    @Herohtar And it means that the same socket model can be used in US and EU products.
    – Nayuki
    Sep 9, 2023 at 15:57
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    There's also some 208/240 V industrial lighting in the US/North America. Streetlights are the most common example, as to reduce the voltage drop and increase efficiency over long cable runs.
    – user71659
    Sep 10, 2023 at 4:24

3 Answers 3

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These bulbs will get hot to touch and the domed fixtures have always contributed to the heat because there's no where for the heat to go, unlike ceiling fan light fixtures and lamps with shades. When the wiring has been compromised, it's usually burnt or darkened exiting the sockets so this looks OK. Flickering is a premature sign of failure.

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  • +1, many bulb lights (and similar) come with an insulated pad to protect the ceiling side from the bulb heat. On some it is often reflective so you get some heat protection and additional light output. As answered, your bulb will probably die before the socket because (right now) the fixture was likely designed for much more heating from an incandescent bulb. Sep 8, 2023 at 17:11
  • @StephanSamuel Good point. This even adds more heat to degrade the electronics in the LED bulbs. I would not recommend removing it though because when you alter the fixture, you void the UL listing.
    – JACK
    Sep 8, 2023 at 17:39
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LEDs generate heat like any electrical device. That's why some have cooling fins. It takes longer and they don't get as hot, but they'll still sting skin if they've been on for a while.

Flickering is a common failure mode--the electronic driver is probably getting weak. If the bulb was seated properly it's likely on its way out the door. They last a good long time on average, but not as long as the early marketing led everyone to think.

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    The light fixture itself seems like it might retain heat. Can a different fixture increase an LEDs life span. Op is worried the wiring might be the cause, but maybe just the design of the fixture could be the cause?
    – crip659
    Sep 7, 2023 at 21:24
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    Well, heat cycle is the primary cause of electronic failure, so sure. That's a very common light fixture design, though, so I'm not inclined to suggest that millions of people should replace them to gain what's probably negligible bulb life.
    – isherwood
    Sep 7, 2023 at 21:26
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    I wonder if that design uses fins because it runs a bit hot anyway, either because it's driving high power LEDs, or because it's not great to start with
    – Chris H
    Sep 8, 2023 at 12:35
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    @ChrisH The fins were common in early LED models for heat dissipation. I still have one that gets daily use, certainly got my money's worth out of it.
    – rtaft
    Sep 8, 2023 at 12:51
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    not as long as the early marketing led everyone to think ...exactly.
    – Fattie
    Sep 8, 2023 at 13:49
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Led bulbs typically fail because their electronics wear out, heat being a prime accelerator of this.

The bulb that was used was not very effective by modern standards at only 66 lm/W. The same amount of light (485 lm) can be made by a 2.3W bulb today, at 210 lm/W.

That will probably prevent overheating of the electronics of a new bulb in the same fixture.

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    I wouldn't go so far as to say "prevent", but "significantly reduce the likelihood". +1 anyway.
    – FreeMan
    Sep 8, 2023 at 11:46
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    210 lm/W would be a very good bulb.
    – AndreKR
    Sep 8, 2023 at 13:03
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    @AndreKR: 210 lm/W is indeed the best I was able to put in my online shopping basket, but it is available
    – Pelle
    Sep 8, 2023 at 13:52
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    @DanIsFiddlingByFirelight Even the Dubai lamp has "only" 200 lm/W, the GU5.3 variant even less. They claim significant longer lifetime though.
    – AndreKR
    Sep 8, 2023 at 20:16
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    @DanIsFiddlingByFirelight Dubai bulbs are illegal in California and therefore not officially sold in the US. They don't meet CA Title 20's >90 CRI and dimmability requirements. The Dubai bulbs have high efficacy, but as people learned from CFLs, quality is important if you want people to use them.
    – user71659
    Sep 10, 2023 at 4:12

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