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

Why does junction box/ceiling rose need to be on ceiling?

Discussion in 'Electrics UK' started by Billpy, 28 Jan 2013.

  1. Billpy

    Billpy

    Joined:
    28 Jan 2013
    Messages:
    11
    Thanks Received:
    0
    Location:
    Glasgow
    Country:
    United Kingdom
    Hi,
    I'm wiring a single ceiling light in my garage (using 1.5mm T+E).
    I've looked at the circuit diagrams here and begun laying the cables this morning. However something is bothering me. Is there a reason why I can't just put the ceiling rose or junction box next to the light switch on the wall? And then run a single cable from the junction box to the lamp, rather than two cables?
    Fair enough, it may look gash, but this is a garage. Aesthetics don't count.
    This would save an extra run of cable (switched live) from the light fitting to the switch, a distance of 5m.
    Since all the switched live does is interupt the feed to the light fitting, why can it not be next to the switch?
    I realise there will be a good reason, but I just can't see it. Thanks.
     
  2. slup

    slup

    Joined:
    14 Jul 2008
    Messages:
    401
    Thanks Received:
    22
    Location:
    Wiltshire
    Country:
    United Kingdom
    Why do you need a rose at all, or indeed a junction box?

    For what you're proposing, just run a supply feed to the light switch, and a load feed out to the light fitting.

    Put the neutrals in a block inside the switch backbox.
     
    • Thanks Thanks x 1
  3. PrenticeBoyofDerry

    PrenticeBoyofDerry

    Joined:
    30 Jun 2009
    Messages:
    21,628
    Thanks Received:
    2,380
    Location:
    Londonderry
    Country:
    United Kingdom
    There is no need for a junction box at all, you can use the switch plate enclosure for connections, providing there is room within it to accommodate them.
    Then you can run a twin and earth cable to the fitting, with live and neutral looped in at the switch plate.
    You will always require a switch live from switch to fitting and a neutral at the fitting, but there is no requirement to strictly loop-in at the light fitting.
     
    • Thanks Thanks x 1
  4. Billpy

    Billpy

    Joined:
    28 Jan 2013
    Messages:
    11
    Thanks Received:
    0
    Location:
    Glasgow
    Country:
    United Kingdom
    That's good. The junction box/rose is redundant then, because I'm only supplying and switching one light fitting?
    So I can just use the switch box for what it is; simply a control for opening and closing a break in the power supply to the light swith?

    I did wonder about this and I think I've wired up lamps that way in the past (in ignorance). It's just I could not see any example diagrams of this, simple method. They mostly show a ceiling rose.

    Thanks for the diagram Derry Prentice, I thought maybe I was missing some important safety feature. This will save a few metres of cable (it's pretty pricey stuff)
     
  5. AdamCH

    AdamCH

    Joined:
    30 Sep 2007
    Messages:
    579
    Thanks Received:
    74
    Location:
    West Midlands
    Country:
    United Kingdom
    Is this only feasible with single switches or can it be used with double & triple switches & 2-way switching? How deep are you chasing the walls?
     
  6. Scoby_Beasley

    Scoby_Beasley

    Joined:
    1 May 2003
    Messages:
    1,881
    Thanks Received:
    50
    Location:
    Durham
    Country:
    United Kingdom
    yes, obviously the wiring config will be different.
    Not sure on what you mean, cable chases are the same depth just wider, but if we feed neutrals to the switch back box, with normal switch plates, we use a 25mm box as the plaster depth ones are too shallow.
     
  7. PrenticeBoyofDerry

    PrenticeBoyofDerry

    Joined:
    30 Jun 2009
    Messages:
    21,628
    Thanks Received:
    2,380
    Location:
    Londonderry
    Country:
    United Kingdom
    It can be done with one, two or three gang switches. You will need to link the permanent live across the common connection and run a twin&earth to each light of gang, to offer a switch live, neutral and CPC.
    Also can be used on two way switching, but obviously you will require strappers across the two ways.
     
  8. AdamCH

    AdamCH

    Joined:
    30 Sep 2007
    Messages:
    579
    Thanks Received:
    74
    Location:
    West Midlands
    Country:
    United Kingdom
    I was thinking that there would be extra cables coming down the wall but guess there would only ever be two extras for the loop regardless of how many swiches.
     
  9. PrenticeBoyofDerry

    PrenticeBoyofDerry

    Joined:
    30 Jun 2009
    Messages:
    21,628
    Thanks Received:
    2,380
    Location:
    Londonderry
    Country:
    United Kingdom
    You will need the supply for L,N and CPC to the switch plate
    The you will only require one t&e to each fitting, as live can be linked across the switches at com, then take a switch live from L1, the neutral from the looped in neutral at connection block and the CPC from earth terminal of back box.
    This goes for single or multiple gangs.
     
    • Thanks Thanks x 1
  10. AdamCH

    AdamCH

    Joined:
    30 Sep 2007
    Messages:
    579
    Thanks Received:
    74
    Location:
    West Midlands
    Country:
    United Kingdom
    Ok to put Wago connectors in metal back boxes?
     
  11. PrenticeBoyofDerry

    PrenticeBoyofDerry

    Joined:
    30 Jun 2009
    Messages:
    21,628
    Thanks Received:
    2,380
    Location:
    Londonderry
    Country:
    United Kingdom
    Yes
     
    • Thanks Thanks x 1
  12. Scoby_Beasley

    Scoby_Beasley

    Joined:
    1 May 2003
    Messages:
    1,881
    Thanks Received:
    50
    Location:
    Durham
    Country:
    United Kingdom
    Best choice in my opinion.
     
  13. AdamCH

    AdamCH

    Joined:
    30 Sep 2007
    Messages:
    579
    Thanks Received:
    74
    Location:
    West Midlands
    Country:
    United Kingdom
    Whoever invented Wago connectors will be feeling quite pleased with him/herself. I was wondering if they are well enough insulated to be left in a metal box.
     
  14. PrenticeBoyofDerry

    PrenticeBoyofDerry

    Joined:
    30 Jun 2009
    Messages:
    21,628
    Thanks Received:
    2,380
    Location:
    Londonderry
    Country:
    United Kingdom
    They need to within enclosures, but wagos are IP rated IP20 and the 733 and 222 series can withstand 400V.
     
  15. DIYnot Local

    DIYnot Local

    Joined:
    3 Sep 2019
    Country:
    United Kingdom

    If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

    Select the supplier or trade you require, enter your location to begin your search.


    Are you a trade or supplier? You can create your listing free at DIYnot Local

     
Loading...

Share This Page