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LED Lights Glowing When Off

Discussion in 'Electrics UK' started by MutleyDoSomething, 25 Sep 2016.

  1. MutleyDoSomething

    MutleyDoSomething

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    Hi. I think I have a wiring fault and need some advice. I fitted some LED bulbs in a ceiling light where the room has 2 light switches. The bulbs have a very faint glow when turned off. My meter shows 7 volts at the light fitting terminals. What on earth could be causing this and is it dangerous?
     
  2. John D v2.0

    John D v2.0

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    That's usually caused by the extra wires for the two way switching inducing a small current in each other. The longer they are, the worse it gets. It's not dangerous but it's very slightly wasteful regardless of the type of bulb.
     
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  4. bernardgreen

    bernardgreen

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    The capacitively coupled power from Live wires to Switched Live wires is enough to "glow" an LED lamp when the switch is off.

    A capacitor in series with a resistor across the supply to the LED will in almost all cases solve the problem. The capacitor absorbs the capacitively coupled power without the voltage being high enough to affect the LED.

    0.1 microfarad 400 volt capacitor polyester and 100 ohm 1 watt resistor have proved sucessful. I would also fit a 1 amp fuse in series as well

    400 volt as it has to cope with the approx 320 volt peaks of 230 v AC It cannot be an electrolytic or polarised capacitor.

    Contact suppressors such as the one below provide the necessary circuit in a single convenient package. The use across LED lamps is not their intended purpose but they do provide the function required.

    http://uk.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=0209241

    Read more: http://www.diynot.com/diy/threads/gu10-led-still-glow-whwn-off.197054/#ixzz4LFoN1qCB

    Maplins also provide a similar item http://www.maplin.co.uk/p/rc-contact-suppressor-rg22y
     
  5. MutleyDoSomething

    MutleyDoSomething

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    Okay, thank you for your replies, I learnt something new today.
     
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