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Under cabinet LEDs running too hot?

Discussion in 'Electrics UK' started by Creatch, 10 Mar 2019.

  1. Creatch

    Creatch

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    Sorry, this isn't strictly DIY but I thought people here might know. I recently had a new kitchen installed. The cabinets have 2.6W Sycamore LEDs recessed into the undersides to cast light over the worktop. However, I soon noticed that the insides of the cabinets were getting pretty hot when the lights were on. So I measured with a kitchen thermometer, with the tip of the probe in the air just above where the LEDs are situated. With the door closed and the lights off, the ambient temperature inside the cabinets is about 22°C. But with the lights on, it goes up to 31.6°C. That's hot enough that spices will go stale really quickly and wine will basically cook in the bottle.

    Can anyone tell me if I'm right to think that's abnormal? The kitchen company contacted Sycamore on my behalf, and Sycamore seemed totally uninterested in the problem. I suggested to the kitchen company that we replace the Sycamore lights with (as I imagine it) more efficient lights from a better brand, but if they claim that if the replacements lights are the same wattage, they will run just as hot. Are they right?
     
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  3. bernardgreen

    bernardgreen

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    That does seem to be too much heat from the lamps.

    How many lamps are there and are they 230 volt or 12 volt ( with a separate power unit elsewhere )

    When you say recessed do you mean the lamps are in holes cut in the base of the cabinet. ?

    Do they go right through the base as in B ?

    upload_2019-3-10_20-2-0.png
     
  4. RichA

    RichA

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    You could swap for some LED strip lights stuck to the underside of the cabinet? That seems to be the norm these days anyway.
     
  5. Creatch

    Creatch

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    Thanks for your reply. They're 12 volt with a separate power converter. And the fittings don't go all the way through the base, they're more like A in your diagram – the heat is coming through the wood.
     
  6. JohnW2

    JohnW2

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    As has been said, it does sound like a surprising amount of heating. As you have been asked, how many lights are there - is it just one per cabinet?

    How long is it taking to get the ~10° temperature rise you mention? Maybe I'm wrong, but I would have thought that, even with a 2.6 W LED inside the cabinet, it would take a good while before one saw that sort of temperature rise.

    Kind Regards, John
     
  7. Creatch

    Creatch

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    Yeah it's just one LED per cabinet.

    It takes about 25 minutes after turning the lights on for the thermometer to read 30+°C.
     
  8. bernardgreen

    bernardgreen

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    I wonder how hot the lamps are.

    If they can force enough heat energy through the wooden ( or MDF ) base of of the cabinet to raise the temperature 10°C in less than half an hour then the lamps are very hot.

    I recall MDF panels resisting the heat from a blow torch for some considerable time before the other side of the panel became hot suggesting that the thermal resistance of MDF is high.
     
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  9. Creatch

    Creatch

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    Very reassuring that other people agree this isn't how it should be. Does anyone have any advice about what I should do next? As I said, the kitchen company's response was "If we installed different lights they'd be just as hot." Is there a way I can prove that I'm right about this?
     
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  11. JohnW2

    JohnW2

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    As we have said, it seems to make little sense. Are you certain that it's not something other than the light which is heating the inside of the cabinet?

    How hot is the light itself getting - can you touch it?

    Kind Regards, John
     
  12. reds42

    reds42

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    That seems a crazy amount of heat from such low power LEDs.

    Is the power supply in the cupboard?
     
  13. flameport

    flameport

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    Are you absolutely certain these lights really are LED?
    and not some old stock 20W halogen things left over from a few years ago?
     
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  14. Creatch

    Creatch

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    Well I didn't physically watch them being unpacked and installed but they are listed as a specific model of Sycamore LED on all the paperwork.
     
  15. Creatch

    Creatch

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    I tried holding the kitchen thermometer to the glass of the light itself. It peaked at 37.7°C – hot, but not too hot to touch.

    I'm afraid I don't know where the power supply is. However, I don't think it can be anything other than the light fittings producing the heat, because it's the same across all three cabinets.
     
  16. JohnW2

    JohnW2

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    If that is an accurate measurement (**), it would seem exceedingly unlikely that it could explain the heating within the cabinets that you are reporting.

    ** 37.7°C is around body temp, so it ought not to feel particularly hot. If it does feel hot, the thermometer is probably under-reporting the temperature of the light.

    Kind Regards, John
     
  17. reds42

    reds42

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    You say you measured it inside the cabinet just above where the light is, but how warm is the rest of the cabinet?

    Could it be your just measuring a small hotspot and the rest of the cabinet is considerably cooler?
     
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