gu10 led still glow whwn off

Discussion in 'Electrics UK' started by dave68, 21 Oct 2009.

  1. dave68

    dave68

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    hi .
    recently changed my gu10 50w bulbs in kitchen 4 in total , for led replacements.
    when lights are switched off there is still a faint glow from leds.

    lights are on 2 way switch circuit.

    any ideas how to resolve.

    thanks.
     
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  3. Steve

    Steve

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    a capacitor, not sure what value, across one of the lamps. Someone else will confirm.

    OOI, it probably wont do them any harm glowing. A bit of night lighting.

    Anyway, that aside, how are you finding LED lamps? Which do you use and how do you rate them?
     
  4. dave68

    dave68

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    thanks for reply
    lights are fine obviously not where near as bright as the 50w halogen , but fraction of power consumption and last a lot longer , so i believe.
    even if still glow when turned off .
     
  5. Taylortwocities

    Taylortwocities

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    It is probably induced voltage. its a good sign that the cables you have installed for the LEDS, including the 2-way switching cabling, is not properly earthed.

    It could be pickup on the extra low voltage side but then you'll have provided the proper separation between the ELV cables and the 230v ones, or didn't you?
     
  6. Steve

    Steve

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    1. They are GU10 - 230v.
    2. Nowhere does he stats these are downlights, they could be integrated into a fitting.
     
  7. dave68

    dave68

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    hi
    these are the single downlight . recessed into ceiling.

    also have some more installed in hallway . again have changed gu10 50w for led but these are fine . when switched off they dont continue to glow.
    these are just on one way switched circuit.

    thanks .dave
     
  8. bernardgreen

    bernardgreen

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    Even with properly earthed system the capacitively coupled power from Live to Switched Live is enough to "glow" an LED lamp.

    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
     
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  9. dewaltdave1

    dewaltdave1

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    I'm having exactly the same problem. Downstairs on 1 way switch is fine. Upstairs on 2 way is staying dim all night.

    Would you need one of those 'filters' per lamp or would one be suffice at the start of a line ? I'm assuming it goes 'in line' on the live?
    Thanks.
     
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  11. studentspark

    studentspark

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    Bernardgreen, How would you go about installing the capacitor?

    cheers
     
  12. Taylortwocities

    Taylortwocities

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    It is installed at the lamp itself. Across switched live and neutral at the lampholder.

    What would be the point of putting it at the origin of the circuit?
     
  13. dewaltdave1

    dewaltdave1

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    I have 6 lamps on one cable run (series is that?) so I wasn't sure if I needed one suppressor across the 1st lamp (or even in the junction) or do I need one per lamp at the lamp.

    Thanks
     
  14. bernardgreen

    bernardgreen

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    One installed across any of the lamps will ( should ) solve the problem for all the lamps controlled by that switch.

    You said "series" , I think you mean in parallel. If they really are six 40 volt lamps connected in series across 240 volt then the snubber which needs to connect between switched live and neutral will have to be located at the one lamp where the switched live appears.
     
  15. SlingersUK

    SlingersUK

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    Hi,
    I have the same problem with some GU10 LEDs in a triple fitting :confused:

    Has anyone tried the capacitor solution and was it successful?

    Lastly, bernardgreen, sorry to be bit thick but I am assuming that you are advocating the capacitor is installed across the fittings screw terminal connectors were the cable actually connects and that you fix it across the live and neutral with suitable shielding to ensure it does not earth the live through the fitting :?:

    Lastly I think this is the solution required because, with my configuration, if I replace one of the three LED lamps with a normal incandescent GU10 the LED's are fine and go out as they should. I've also had a meter on this and there is no current I can detect at the lampholder. I've also completely disconnected the live feed at the switch and this had no effect.
     
  16. Steve23

    Steve23

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    Bernardgreen, the capacitor you recommend through the link is 0.22 microfarad. I have got one same spec but with 0.1 microfarad as in your post. What difference does this make please
     
  17. bernardgreen

    bernardgreen

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    A 0.1 microfarad capacitor will work. The longer the cable to the switch then the more capacity there is between the live and switched live for the leakage of current. For very long switch runs a 0.22 microfarad may be needed. For most domestic situations a 0.047 microfarad seems to suffice.
     
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