1. Visiting from the US? Why not try DIYnot.US instead? Click here to continue to DIYnot.US.
    Dismiss Notice

Taking Power From Socket For Light Switch

Discussion in 'Electrics UK' started by DeludedAussie, 17 Feb 2013.

  1. DeludedAussie

    DeludedAussie

    Joined:
    20 Jan 2013
    Messages:
    180
    Thanks Received:
    0
    Location:
    London
    Country:
    United Kingdom
    I have read the wiring diagrams on this website but i am confused. I want to do something very simple.

    I want to take power from a socket and put this into a light switch

    What I thought would work is:

    1) Cable from socket with brown and brown in choc box and blue and blue in choc box to light switch

    2) Brown in com and blue in l1

    3) From same light switch I have a cable with brown connecting to brown and with blue to blue

    So in short all the colors match when connected

    The problem is this causes the RCD to trip and I cannot explain why

    Can someone lend a hand on what I am doing wrong please

    I ve attached pictures which hopefully shows what I am doing - The brown and red from socket is being joined together
     
  2. Sponsored Links
  3. Jackrae

    Jackrae

    Joined:
    20 Nov 2012
    Messages:
    2,183
    Thanks Received:
    365
    Location:
    Dumfriesshire
    Country:
    United Kingdom
    "In short" yes it well and truly is. If I interpret your description correctly your light switch places a direct short across your system when you turn the switch ON. The result is a massive overload which trips the "RCB" don't you mean MCB. Apart from that you cannot run a lighting circuit from a 30A ring main, you cannot use flexible cable buried in a wall and the flexible cable you have used in incapable of passing the current that the socket power circuit is designed to supply. :(
     
  4. EFLImpudence

    EFLImpudence

    Joined:
    7 Jul 2010
    Messages:
    35,766
    Thanks Received:
    3,998
    Location:
    Retired to:
    Country:
    Portugal
    Plus -

    The socket has no back-box or pattress.
    It doesn't look new. How has it been fixed to the wall?

    The socket has only one cable indicating it is a spur so no further wiring should be taken from it without fusing-down before the socket.
    It could be the last on a radial but that would be unlikely.


    You say you have read the diagrams on the site but you will not have seen a switch wired as you have.
    Draw a diagram of what you have done and think what will happen when you 'close' the switch and what you need to happen for the light to work.

    [​IMG]
     
  5. DeludedAussie

    DeludedAussie

    Joined:
    20 Jan 2013
    Messages:
    180
    Thanks Received:
    0
    Location:
    London
    Country:
    United Kingdom
    Thank you very much for your help

    I have tried to take a cable direct from the socket (bypassing the switch) straight to a light and it does work. The light comes on and there is power so I do not think it is a radial.

    The problem occurs when I try to involve the light switch and you are right that the mcb trips.

    Given that the light works when taking power from socket directly it must be because of how I am wiring the light switch.

    I assume that I need one way switching so my brown live is coming from the power socket to the com port and my blue neutral is coming from the power socket to L1 on the switch. From my light switch I have another cable which will hopefully be the cable I use for the light.

    The switch is there just to allow me to switch on and off the light.

    Am I correct in thinking that the colors need to match at the light switch because ths is what I have done.

    Any help appreciated. I tried to draw a diagram but I had difficulty. Could you explain how the cable (from power socket) should be fed into light switch and how cable out of light switch (for the light) should be wired

    I am trying to learn electrics by doing small things in my house

    EDIT: Should I have two additional cables going into the socket to make a ring (making a total of three)? Your help mostly appreciated
     
  6. EFLImpudence

    EFLImpudence

    Joined:
    7 Jul 2010
    Messages:
    35,766
    Thanks Received:
    3,998
    Location:
    Retired to:
    Country:
    Portugal
    Ignore the cable marked 'OUT'.

    You must understand before continuing.

    [​IMG]

    If the socket circuit is controlled by a 30A fuse or 32A mcb then
    you will still need a 13A fused connector before the socket and a 3A fused connector after the socket before the light wiring.
     
  7. DeludedAussie

    DeludedAussie

    Joined:
    20 Jan 2013
    Messages:
    180
    Thanks Received:
    0
    Location:
    London
    Country:
    United Kingdom
    thanks somuch

    the switch has a 10amp fuse already - is that enough?
     
  8. ban-all-sheds

    ban-all-sheds

    Joined:
    27 Aug 2003
    Messages:
    69,783
    Thanks Received:
    2,858
    Location:
    London
    Country:
    United Kingdom
    Your switch has no fuse.

    PLEASE stop all your fiddling with things you don't understand until you've spent some time learning and you do understand. Right now you're an electrocution and/or fire waiting to happen.


     
  9. ericmark

    ericmark

    Joined:
    27 Jan 2008
    Messages:
    17,570
    Thanks Received:
    1,630
    Location:
    Llanfair Caereinion, Nr Welshpool
    Country:
    United Kingdom
    Instead of light switch use a switched fuse connection unit this will do two things.

    1 - It will give you both line and neutral connections on the switch no need for chock blocks for neutral.
    2 - You can fuse down to 3 amp.

    Maximum allowed for lighting is 16A and most ring circuits are 32A so needs fusing down. Many light fittings only rated at 5A so likely a 3A fuse is required.

    [​IMG]

    As you can see look like a switch but have fuse and behind there is both line and neutral connections.
     
  10. Sponsored Links
  11. DeludedAussie

    DeludedAussie

    Joined:
    20 Jan 2013
    Messages:
    180
    Thanks Received:
    0
    Location:
    London
    Country:
    United Kingdom
    I tried this exact approach (which is simple) and the RCD tripped.

    I have two blues together and one brown in Com and one brown in L1 and the MCB tripped.

    Any ideas why?
     
  12. Aragorn84

    Aragorn84

    Joined:
    3 Sep 2008
    Messages:
    1,068
    Thanks Received:
    116
    Location:
    West Lothian
    Country:
    United Kingdom
    You put both of the blues AND the brown in com?

    If so, Thats why.
     
  13. Scoby_Beasley

    Scoby_Beasley

    Joined:
    1 May 2003
    Messages:
    1,881
    Thanks Received:
    50
    Location:
    Durham
    Country:
    United Kingdom
    Thanks to EFL It should look exactly like:

     
  14. EFLImpudence

    EFLImpudence

    Joined:
    7 Jul 2010
    Messages:
    35,766
    Thanks Received:
    3,998
    Location:
    Retired to:
    Country:
    Portugal
    And Flameport.
     
  15. Scoby_Beasley

    Scoby_Beasley

    Joined:
    1 May 2003
    Messages:
    1,881
    Thanks Received:
    50
    Location:
    Durham
    Country:
    United Kingdom
    I was thinking of removing the name as well. :LOL: :LOL: :LOL:
     
  16. Monkeh

    Monkeh

    Joined:
    25 Jan 2010
    Messages:
    4,149
    Thanks Received:
    329
    Location:
    Cornwall
    Country:
    United Kingdom
    How's that?
     
  17. DeludedAussie

    DeludedAussie

    Joined:
    20 Jan 2013
    Messages:
    180
    Thanks Received:
    0
    Location:
    London
    Country:
    United Kingdom
    hi i put one brown in com one brown in l1 and two blues together in l2
     
Loading...

Share This Page