Led security light problem

Discussion in 'Electrics UK' started by jimjones235, 17 Dec 2018.

  1. jimjones235

    jimjones235

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    We had a spark put some power out to our garage several months ago. He used a spur off the ring main (I wasn't too happy with this). He install two pir led security lights on this circuit. After a couple of months they stopped working (the light up but are really dim), I gave up waiting on the spark coming back to fix it, and replaced one of them (as a trial) with a different light from screwfix (it's actually a much brighter light) and it worked fine until today.. Now it just lights up dimmly a little like the one it's replace (different brand etc).. It looks like it tries to fire up the leds as it flickers then goes dim when it should come on... Any ideas?

    As a side note, today I've done some jobs around the house, one of which was to convert some 12v downlighters to mains led (by removing the transformers and replacing the lampholders) they work fine, and I'm not convinced I could have done anything which would have impacted the security light (different circuits, just a straight swap out etc) so it may be jyst coincidence.. Though it may be relevant that the reason we were changing them is that over the past few months we've had a few transformers go - house is 7 years old so it just maybe they are coming to the end of their lives(seems pretty rubbish to me)..

    Should we be looking for an electrical fault, or could we just be having bad luck with the security lights?p
     
  2. flameport

    flameport

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    Security lights failing because they are cheap rubbish from screwfix.
    Cheapo downlight transformers suffer the same problem.

    Changing lampholders or any other wiring does not cause unrelated lights to fail.

    For replacements, get decent quality lights such as : https://cpc.farnell.com/c/electrical-lighting/lighting/outdoor-lighting?brand=ledvance&range=inc-new
    and a separate PIR sensor so you can actually aim the sensor where it works properly and also have the lights illuminating the ground rather than the neighbour's bedroom windows.
    10W or 20W versions should be more than plenty.
     
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  4. Luckyphil

    Luckyphil

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    Is there a Flourescent Light in the Garage ? , some LED/PIR Floodlights seem to have a problem working on the same Circuit , in fact on Mini - Sun LED Floods there’s a sticker that says don’t use on the same Circuit

    Phil
     
  5. jimjones235

    jimjones235

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    An update on this:

    3 more led flood lights blew.

    I had to tweak the wiring in the garage for another purpose 12 months ago, and discovered that the spark who'd wired up the garage spur had reversed the polarity. So live to neutral and vice versa. I changed that back to what it should be and since then the problem has gone away, no more blown led floodlights. So leaving this here incase anyone has similar issues with PIR floodlights dieing.
     
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  7. ericmark

    ericmark

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    I wish I knew why, but your not the only one to have problems with LED lights, my son has had same problem, as @flameport says could be simply cheap lamps, his was cheap, but saying that all mine are also cheap, so either cheap does not mean low quality, which is possible. Or there is some thing else?

    I can't answer your question, however would be interested to know if you have a surge protection device (SPD) fitted? I have one fitted here, lost one LED lamp, son does not have them fitted, he has lost many. Well I say that, filters, and SPD are not only built into consumer units, but also extension leads and other equipment, also also over head supplies are more likely to get surges or spikes in the first place.

    Some devices due to way they are made can better handle spikes and surges, and the spike or surge could be from a simply poor quality light switch, so local to that device, but we know devices now including LED lights have electronics before the step down transformer if they even have a step down transformer, where years ago most electronic equipment was supplied from a power supply, which would likely remove or at least damp down any spikes or surges.

    The filters fitted often connected to earth years ago, but these added to earth leakage, and could cause the RCD to trip as they all added up, the practice of having many circuits on the same RCD had not helped, we are told 3.5 mA is the maximum permitted leakage, but if they leaked that much one would have a problem keeping a RCD in with multi circuits, so even where filters are fitted, they are not as good as they were.

    I have some filtered sockets with renewable modules, I have never renewed on, so anyone's guess if still working.

    Clearly running LED's under driven will help them last even with surges or spikes, so some makes will last better than others, where they are not run to their maximum. So the poor quality idea is still true, even if helped by spikes, without an oscilloscope it is guess work, and even with one the spikes are so short you may not see them.

    However if enough people report if they have a SPD fitted when they loose LED lamps then it may in the fullness of time show a trend, and we may get a better idea if the failures are due to spikes or surges on the supply.

    In university we tested red LED's to try and increase output, we pulsed the LED giving up to twice it's rating but for half the time, the experiment was a failure, as the lux meter used auto compensated for flashing lights so although out eyes perceived more light the measuring equipment failed to record it. However during these experiments it was found once a LED had been over driven its light output reduced even when returned to the rated current, and the description of your dim LED's is the same as we got with over driven LED's in our experiment, so it does seem at some point they have been over driven.
     
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