Light switch wiring…

Discussion in 'Electricians' Talk' started by Was123, Jul 8, 2022.

  1. Was123

    Was123 New Member

    Hi,

    Image link: https://ibb.co/r5d8xRG

    Moved into a new place. Going to replace the outside light. There is a light switch directly behind the outside light (but on the inside of the house). There is nothing else that this light switch can control.

    The outside light feed is dead. I removed the light switch. The only wire that is live is the one currently plugged into the back of the switch. The neutrals are in connectors blocks and the earth has been stripped back.

    From the two sections of 1.5mm t&e one is live and connected to the com position in the back of the switch - is this likely to be live feed? If so, should I take the other live cable (which goes to the outside light feed) and insert this live conductor into the com terminal and leave the two neutrals in the connector block?

    Hopefully this will feed power to the outside light as the old owner had before they moved out (and took their outside light with them).
     
  2. MGW

    MGW Screwfix Select

    When I moved in here I could not believe how the house was wired, it seems there had been some major changes when the garage was turned into a flat, one would have expected since the installer produced an installation certificate and stuck their name on the consumer unit it would be reasonable, but no.

    You have to test and find out.

    And if you want people to look at the picture, embed it in the post, no one wants to go to some other site to view it. When I find some thing disconnected I ask myself why, I had it with three core and earth which left main house as red, yellow, blue, and arrived in old garage as brown, black, grey, with one core open circuit, I had two options, try and find it in the wall, or fit 12 volt controls so would not matter if anyone touched the cable where jointed, I went for 12 volt.
     
    Last edited: Jul 8, 2022
    tore81 likes this.
  3. tore81

    tore81 Screwfix Select

    Any photos? Can’t you test the cable polarity. To confirm it’s the correct cable?
     
  4. seneca

    seneca Screwfix Select

    which goes to the outside light feed

    Put this one into the other side of the switch, (possibly marked L1 or L2)
     
  5. Was123

    Was123 New Member

    Hi All,

    Thanks for the pointers. I simply used some testing equipment to isolate which of the two cables goes outside. The Live shown in the pic is from the cable going outside but it was terminated behind the light switch. Both neutrals are connected to a CB. Both earths are connected together at the right earthing point. It was just a connection of stripping back the live cable that was terminated behind the light switch and inserting it into the L1 of the light switch to make the circuit complete. Flicked the breaker back on for the lighting and the cable that went to the old outside lights now has power. The switch functioned properly as when switched off, tested the cable to the outdoor lights was off (which it was). Floodlight has now been installed.

    I'm trying to minimise the visible cable. I am trying to find an IP 66 (min rating), Wiska box with rear entry but can't seem to find anything suitable along with the right compression glands that will handle 1.5mm flex, 1.5mm T&E as well as 20mm conduit.

    Any ideas on this?

    WhatsApp Image 2022-07-09 at 12.53.05 AM.jpeg
     
  6. Teki

    Teki Screwfix Select

  7. Was123

    Was123 New Member

    Thanks a lot for this.

    Some great links.
    https://www.tlc-direct.co.uk/Products/EK251W.html

    ^^^ will this take 1.5mm flex? It says it starts at 6mm?
     
  8. The Happy Builder

    The Happy Builder Screwfix Select

    Wiska boxes have self-sealing rear entry ports.

    [​IMG]
     
  9. Was123

    Was123 New Member


    Thanks for this, Can these rear entry ports handle 1.5 or 2.5mm T&E?
     
    seneca likes this.
  10. seneca

    seneca Screwfix Select

    Yes they can.
     
  11. Was123

    Was123 New Member

    What can Wiska boxes not do! Brilliant invention.

    Has anyone get any compression glands that will handle 1.5m2 flex? Most of the CG (such as https://www.tlc-direct.co.uk/Products/EK251W.html) start at 6mm.

    Thanks!
     
  12. Teki

    Teki Screwfix Select

    Typical 3-core 1.5mm² flex has an O.D greater than 6mm. As an example:

    https://www.tlc-direct.co.uk/Products/CA1dot5F3slash50.html

    Measure the O.D of the flex supplied with your light first.

    Alternatively, I believe this box has self-sealing membranes on the rear and sides:

    https://www.toolstation.com/junction-box-ip65/p61729
     

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