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I have four LED GU10 lamps in pendant fittings on the same circuit with six fluorescent tubes in my workshop, all 240 V mains. I have noticed high failure rate in the LED bulbs.

I think this could be because of an interaction with the fluorescent tubes.

Should they be on separate circuits, or do I just have a batch of poor quality LED bulbs?

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  • Of course you’re right - I wasn’t thinking clearly when I wrote that. I’ve amended the question.
    – Daniel
    Jul 26 '20 at 15:11
  • it shouldn't have anything to do with the fluorescent lights. If the LED bulbs/lamp fixtures are too hot to touch after an hour on, they are over-heating, and that's the issue. Or they could just be cheap LEDs and your workshop could have spiky power which call the card of the LED's weakspots.
    – dandavis
    Jul 27 '20 at 12:35
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Are the GU10 lights embedded in the ceiling as downlights? Most downlights haven't been redesigned to use LED's vs halogens and therefore have no air circulation since the hot bit (LED and driver electronics) are withing the ceiling cavity. This trapped heat wasn't a problem for halogens but are a massive issue for solid state electronics with high temperatures causing premature death. The reason why the fluorescent tubes haven't failed is because of their higher surface area and the fact they are surface mounted on the wall rather than in the wall and therefore stay cooler.

This problem is compounded by manufacturers using the same heatsink for the their entire range of GU10's regardless of wattage. 2W to 6.5W all have the same heatsink area since it's cheaper for the manufacturer to bulk order one part rather than 3 to 5 different sizes. Therefore the 6.5W GU10 bulbs often fail much sooner as they get much hotter.

My suggestion would be to buy bulbs with a long warranty (some have 5 yrs like the Philips LEDspot ExpertColor GU10) and just ask for replacements when they inevitably go bang. Other options are installing more downlights and using 2W bulbs rather than 5W bulbs which should last longer and produce the same amount of light or using downlights designed for LED's with a greater heatsink area on the hot end - these are sadly rare.

EDIT: Pendant fittings also have a similar issue to downlights if there is no air circulation. Here is an engineering approach to the problem but I doubt it would please any any interior designers. The principle is the same though - heat is the enemy (Although massively simplified you can blame Arrhenius for this fact).

Ensure your pendant has adequate air circulation.

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  • Yeah, long term, I'd look at changing the downlight fixtures out to decent integral-LED units as those will have better thermal management than a LED bulb in a halogen downlight fixture Jul 26 '20 at 18:56
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    Those are valuable comments, but actually these are just pendants, so in my specific case the bulb itself is in free air
    – Daniel
    Jul 26 '20 at 19:20
  • That's why it's so important to be very specific when you ask questions, @Daniel. The more detail you can provide in your initial question, the better the answers will be.
    – FreeMan
    Jul 26 '20 at 19:23
  • Valid point - I’ve amended the question wording, thank you
    – Daniel
    Jul 26 '20 at 19:32

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