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

Garage light

Discussion in 'Electrics UK' started by dormermike, 3 Dec 2019.

  1. dormermike

    dormermike

    Joined:
    1 Mar 2011
    Messages:
    733
    Thanks Received:
    13
    Location:
    Cardiff
    Country:
    United Kingdom
    Hello

    Would appreciate if someone can double checking my understanding here please before I make changes.

    My garage has a consumer unit powered off the house CU via a RCD. Within the garage there is a single light fitting (fluorescent) which is on a loop from the garage CU via a wall switch.

    I would like to add a second light which is itself switched via a pull chord. The second light should only work when the wall switch is on.

    I opened the flourescent fitting and I noticed the switched live (neutral with red tape) is connected directly to the red live. That confused me a bit, because the actual light fitting doesn't seem to have its own switched live. Presumably this means the switched live is energising the live (black with red tape, to red) which then loops via the CU to the light fitting?

    Is the correct way to add the second light fitting simply to add a new twin and earth to the light fitting choc block?

    Thanks
    Mike

    e 20191203_124138.jpg
     
  2. Sponsored Links
  3. EFLImpudence

    EFLImpudence

    Joined:
    7 Jul 2010
    Messages:
    30,261
    Thanks Received:
    3,274
    Location:
    Retired to:
    Country:
    Portugal
    Yes. The block in the light.

    Your confusion is in thinking 'neutral' means 'black'. It does not.

    Neutral is the name given to the conductor which completes the circuit from the load(light) back to the supply.
    Its colour is irrelevant.
    Wires can be anything we want them to be. They do not know what colour they are.
     
    • Thanks Thanks x 1
  4. dormermike

    dormermike

    Joined:
    1 Mar 2011
    Messages:
    733
    Thanks Received:
    13
    Location:
    Cardiff
    Country:
    United Kingdom
    Thanks!

    Yes I see what you mean, I wrote neutral with red tape but should have written black with red tape. Just looked a bit odd to me but I'll piggy back off the other choc block as you confirmed. Cheers
     
  5. dormermike

    dormermike

    Joined:
    1 Mar 2011
    Messages:
    733
    Thanks Received:
    13
    Location:
    Cardiff
    Country:
    United Kingdom
    Finally got around to looking at this as I want to wire up the second light.

    I just can't get my head around what is going on.

    The black wire with the red tape around it and the red wire both going into the single connector block (hanging down) are at 254v relative to the black wire in the 3way block inside the light fitting.

    So that wire hanging down is live all the time basically.

    Why would that be? A second switched set of lights perhaps, independant of the existing wall switch ?

    Thanks
    Mike
     
  6. eta

    eta

    Joined:
    24 Apr 2008
    Messages:
    271
    Thanks Received:
    11
    Location:
    West Sussex
    Country:
    United Kingdom
    Live ("All the time") , neutral & Earth comes in on one set of T&E - lets say T&E 1
    then to use the switch the live Live ("All the time") is connected to the 2nd T&E - black with RED tape , goes back to the switch as live and then the RED from the 2nd T&E comes back form the switch to the light block
    So when you use the switch it uses the RED/BLACK with red tape and switches over to the RED wire on the 2nd T&E making it live and back to the Light block
    Normal way a Light is often setup , so you can pick up the Live Neutral & Earth and daisy chain to next light and then use another T&E to got a switch

    if that is correct description, as the RED wires , and not 100% clear on the image

    then if you want to use the same switch to switch another light - USE another T&E and connect to the light block itself and out to the next lighr
     
    • Thanks Thanks x 1
  7. Sponsored Links
  8. securespark

    securespark

    Joined:
    11 Jan 2004
    Messages:
    33,452
    Thanks Received:
    1,010
    Country:
    United Kingdom
    The only slight confusion here is that "usually", the live coming in (the red wire in the cable where the black connects to the fluorescent fitting's terminal block) is connected to the red of the cable that goes to the switch, then the switched live (black marked with red) connects to the fitting's terminal block.

    In this case, the incoming live is connected to the black marked with red and the switch wire returns from the switch on the red wire.
     
    • Thanks Thanks x 1
  9. dormermike

    dormermike

    Joined:
    1 Mar 2011
    Messages:
    733
    Thanks Received:
    13
    Location:
    Cardiff
    Country:
    United Kingdom
    Thanks all for your help. All done. I had isolated the lighting circuit at the garage consumer unit and left the sockets turned on. At some point the RCD in the house tripped. Guess I'm glad there was an RCD!!

    New light fitted and working and there are no odd smells or smoke! Result.

    Happy christmas!!
     

    Attached Files:

  10. dormermike

    dormermike

    Joined:
    1 Mar 2011
    Messages:
    733
    Thanks Received:
    13
    Location:
    Cardiff
    Country:
    United Kingdom
    Been puzzling over why the RCD tripped, can anyone help me understand that please?

    Basically I have an RCD protected feed to the garage which has a CU with 3 circuits on it. Lighting, External gate (always off, not used), sockets. Turned off the lighting to install a new light, and the sockets stopped working because the RCD in the house had tripped. As the lighting circuit was off at CU I don't understand why the RCD tripped.

    Thanks
     
  11. DetlefSchmitz

    DetlefSchmitz

    Joined:
    17 Aug 2010
    Messages:
    1,816
    Thanks Received:
    231
    Country:
    United Kingdom
    You probably shorted N to E, while fixing the light.
     
    • Thanks Thanks x 1
  12. dormermike

    dormermike

    Joined:
    1 Mar 2011
    Messages:
    733
    Thanks Received:
    13
    Location:
    Cardiff
    Country:
    United Kingdom
    Doh, of course! Thanks
     
Sponsored Links
Loading...

Share This Page