How to change 2 gang 1 way dimmer to normal switch

Discussion in 'Electrics UK' started by SG, 25 Sep 2010.

  1. SG

    SG

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    Hi all, firstly I'd like to say what a great website, have been browsing for a while but only just signed up today!

    Got a bit of a problem that I'm hoping someone might be able to point me into the right direction?

    Basically in our living room we have a ceiling rose with 3x lights on it, plus 2 sets of wall lights with 2x lights on each 'rose' on the wall - these have on/off pull switches as well.

    For some reason whoever lived here/owned this house before fitted dimmer switches for these lights, however they don't actually dim any lights they just turn them on and off.

    Today I went to wickes and bought replacement 2 gang switches which I want to fit in place of these dimmer switches.

    The problem is the wiring here is quite old and kinda dodgy - it's a rented house and apart from making the landlord get someone to fit a consumer unit (we had some ancient grey box with an on/off switch) he isn't interested in fixing anything in the house so until we gather enough cash for a deposit on a house to buy, I want to make the house reasonably safe for us in the meantime without spending lots of cash.

    I unscrewed the dimmer switches off the wall and had a look at the wiring behind them. There are 5 copper wires, ALL red in colour (!) with 4 coming from behind the wall. It's wired up like so:

    [​IMG]

    How do I wire this up to the new switches I bought today?

    Annoyingly, there are NO markings whatsoever on the back of the dimmer switches so I'm not sure which wires go to COM/L1 etc. etc.

    Any ideas?

    Thanks,
    Sam
     
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  3. 333rocky333

    333rocky333

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    your drawings are unclear they would not work like that.
    Was there short links in the two switches, and how do you know that red link is between the two switches.
     
  4. SG

    SG

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    This is exactly how it is wired - I drew the diagram on paper with the switches off the wall and double-checked them.

    There are two pairs of red wires coming from the wall, and one red link wire running down the side as per my diagram.

    The lights do work as I'm typing this in the room they are in...
     
  5. 333rocky333

    333rocky333

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    I assume that is two doubles (4 dimmers) in your drawing
    how many actually work the lights.
     
  6. SG

    SG

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    Sorry I forgot to say in my original post - it's just a 2 gang switch (i.e. 2 dials to turn ceiling/wall lights on and off).

    The diagram is of the back of the switches by the way.
     
  7. 333rocky333

    333rocky333

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    :confused:

    what do the four squares in the drawing represent
     
  8. Christhescott

    Christhescott

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    The four squares are the terminals yes?

    Then the two terminals with 2 wires in them are the common terminals and the terminals with 1 wire each are the 1 way terminals.
     
  9. 333rocky333

    333rocky333

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    If they represent 4 terminals on the back of a 2 gang dimmer

    use common and common for the two red wires and
    L1 and L1 for the single reds

    if the switches are upside down after Then move the single red ones from L1,L1 and use L2 and L2
    If your new switch is metal it Must be Earthed also.
     
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  11. ban-all-sheds

    ban-all-sheds

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  12. SG

    SG

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    Thanks guys. Right, so just to confirm you are both saying:

    COM = terminals with two wires in them
    L1/L1 = terminals with single wires in them

    When I connect the 4 wires up to the respective terminals in the new switch I bought yesterday, do I need to do anything with that extra 5th linking wire - i.e. do I connect it between the two COM terminals as per the current wiring (if so, how come?).
     
  13. SG

    SG

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    I did look at this first yesterday before posting and I assumed the terminals with the 2 wires in them were the COM terminals but I wanted to ask you lot your opinions first just to make sure. Thanks.
     
  14. sparkydude

    sparkydude

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    You need all wires to make this work, as said before the two terminals with TWO cables in each will be the COMMON, ie the power in and out of the switches. The other SINGLE cables in each switch are the Switched Lives and they go to the lights.

    YOU MUST USE ALL 5 CABLES OR ELSE IT WILL STOP OTHER LIGHTSB WORKING IN YOUR FLAT.

    Nick
     
  15. SG

    SG

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    Thanks Nick.

    I'm sure I probably come across as being a bit thick here, but I just wanted to know - why is the link wire needed?
     
  16. ban-all-sheds

    ban-all-sheds

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    Best guess is that you have one permanent live coming in, and the link wire is creating one which goes off somewhere else.

    Try wiring it up without the link and see what else stops working apart from the other light on that switch.
     
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