Help fitting a two-gang dimmer switch

Discussion in 'Electricians' Talk' started by Camero, Aug 1, 2015.

  1. Camero

    Camero New Member

    I'm trying to fit a dimmer switch in my living room. I have two pendent lights controlled by a single wall socket with two switches one for each light. My property is a new build and in the UK.

    So much for thinking this would be as easy as unwiring the wires and wiring them into the same places on the new dimmer switch!

    My current standard wall socket is wired like so:

    [​IMG][​IMG]

    This seems a lot more complicated than just a few wires to swap. There appear to be multiple cables coming out from the wall. The Green/Yellow earth is loose in the backplate with a plastic end cap.

    Coming out of the wall are 2 brown wires 1 for each switch currently going into the L1s.

    There are then four blue wires coming out of the wall two for each switch going into Loop (N) sockets. One of the wires is stripped about three inches from the end of the wire and then bent it's the bent striped part that is in the first socket Loop then end of which then goes into the other Loop socket. So one wires basics bridges to the other socket.

    It's the same setup for the other two brown wires that come out of the wall , one of each goes into the Com sockets and again the first brown wire bridges over to the second Com socket.

    My new 2-gang 400W dimmer looks like this:

    [​IMG]

    Problem is new dimmer switch does not have a socket labeled N Loop. I tried replicating the wiring but where on the original sockets the wires are in the N (Loop) ports, I've just put them in L2 on the new socket as that was the only other port unused.

    It seems the old switch has Com, N (Loop), L1 and L2 ports, but the new dimmer socket only has L1, L2 and Com.

    I tried this setup and it kind of worked if lights were on and the lights did dim (though flicked, maybe wrong energy bulbs) but when I tried to turn them off they blow trip the fuse in the main fuse box.

    As you can probably tell I know nothing about wiring or these kind of things. Any help or pointers anyone could give me would be really appreciated.

    I was wondering if I have the wrong type of light switch but I can't find any other types.

    I've also included a photo of the instructions though they don't really mean much to me and don't really correspond to the original wiring for the original socket.
     
  2. seneca

    seneca Screwfix Select

    The N loop terminals are just "parking" points for the neutrals so put those all together in a piece of connector block.
    The L1's go into the L1's of the dimmer and the commons go to the common's of the dimmer, (strapped together as at present)
     
  3. Camero

    Camero New Member

    That's really helpful, so the N Loop terminals are just convenience in the old socket.

    So what is the point of the earth and neutral cables that come out of the wall if they are just terminated in a block?
     
  4. KIAB

    KIAB Super Member

    It's just one way of completing a circuit.
     
  5. Camero

    Camero New Member

    Got it, thanks guys makes lot more sense to me now. I'll let you know if you blow the house up!
     
  6. Camero

    Camero New Member

    Can anyone recommend a connector block to purchase?
     
  7. KIAB

    KIAB Super Member

    Just need a 5a terminal strip, so you'll have to get one off the High Street, Wliko 45p.

    Just need to cut off two terminals from it.


    [​IMG]
     
    Last edited: Aug 1, 2015
  8. Camero

    Camero New Member

    Cool, I'll pick one up and give it a go, thanks.
     
  9. KIAB

    KIAB Super Member

    There might be one issue, & that's space, what with thickness of dimmer, & terminal block, it might be a sqeeze getting it all in the metal box if it's a shallow one.
    Might be easier using seperate terminal strips, instead of a pair, then they can be laid flat in the box.
     
    CGN likes this.
  10. peter palmer

    peter palmer Screwfix Select

    If you have stuck the neutrals in the L2 connection in the dimmer I dont hold out much hope for the dimmer switch now. Also The 4 neutrals all need connecting together, you can use 1 block for this and do away with the blue link. Same for the earths, you need to maintain continuity through the cables.

    How are the earths terminated presently, they usually go to a stud on the back of the box, unless its a fast fix box and then they would need another connector.
     
  11. seneca

    seneca Screwfix Select

    Where does it say he's put the N's into the L2 dimmer terminal Peter? I certainly didn't tell him to do that!
     
  12. peter palmer

    peter palmer Screwfix Select

    His first paragraph under the picture of the dimmer in the first post.
     

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