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Wiring Advice - New Lights

Discussion in 'Electrics UK' started by bigalxyz, 19 Apr 2021.

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  1. bigalxyz

    bigalxyz

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    I’ve just removed my old doorbell, which was wired through the mains (replacing it with a more modern cordless doorbell).

    This left me with a bit of mains flex sticking out of the wall just above my fusebox in a hallway cupboard. I’d like to use that to power two 11W LED ceiling lights (bought from screwfix last week) - one in said cupboard, and one in the cupboard next door. Also a simple 1 way switch on the wall of each cupboard.

    Is there a handy wiring diagram out there that I could use? And the circuit that this mains lead is on (“smoke alarms and doorbell”) isn’t protected by an RCD, so will I need to fit one of these as well?

    Is any wiring to/from the lights and the switches best done underneath the plasterboard, or is surface wiring ok (inside plastic trunking, which I have lots of)?

    For the moment I’ve terminated the lead inside a junction box (pending my next move) rather than just leaving it dangling.

    I could get an electrician to do this of course, but I’d quite like to do it myself (cheaper and more satisfying) - but only if I’m sure I can do it legally and safely.

    Thank you.
     
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  3. AndyPRK

    AndyPRK

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    Yeah you could put the switch where the door bell was. Or use the junction box to extend the cable to the switch.

    The black wire needs to run to the light.
    The red wire needs to go via the switch.

    If you use surface wiring you shouldn’t need an rcd
     
  4. davelx

    davelx

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    "411.3.4 Additional Protection for circuits with luminaires
    Within domestic (household) premises, additional protection shall be provided by an RCD" etc.?
     
    Last edited: 20 Apr 2021
  5. bigalxyz

    bigalxyz

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    if I do need an RCD, what’s the easiest way to include one?
     
  6. TimboTwo

    TimboTwo

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    Please post a photo of your consumer unit.
     
  7. ColJack

    ColJack

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    Things have apparently changed since I last picked up the book.
    You don’t need RCD on lights if you can see the wiring.

    look in the stickies for wiring diagrams.

    basically you take the cable sticking out of the wall and put it in a junction box ( since it’s probably not long enough to reach the switch or light )
    From there you take a twin and earth down to the switch and one from the switch to the light.
    Connect the blue wires together in a suitable connector in the back is the switch box ( or you can use double pole switches ) and put the brown wire from the junction box cable into the C or Com terminal of the light switch.
    Then put the brown wire from the light into the L1 terminal of the switch.
     
  8. bigalxyz

    bigalxyz

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    voila

    And I’ve just noticed the “recommended date of next inspection” sticker. I’m only 10 years late (n)
     

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  10. bigalxyz

    bigalxyz

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    Thank you. I hadn't seen the stickies - have had a look now. I've found a nice YouTube video from a British electrician who has his own channel and he builds this exact layout in nice, simple stages. So I'm happy...except for the RCD question, which seems to have divided opinion here.
     
  11. davelx

    davelx

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    It seems to me that the regulation I quoted, 411.3.4 (typo in earlier post corrected) which is on page 59, is completely unambiguous. Lighting circuits in dwellings require RCD protection regardless of how and where the cable is run.
     
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  12. bigalxyz

    bigalxyz

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    Yeah it does seem that way. The YouTube video I watched mentioned it too (and the video was made just a few months ago so I guess relates to the regs as they are today). Nuisance. The great irony of course is that my existing lighting circuits aren’t protected in that way because presumably the regs didn’t require it at the time of installation.

    Time for me to pause and have a rethink.
     
  13. plugwash

    plugwash

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    It is true that BS7671:2018, AKA the "18th edition" requires RCD protection for circuits supplying luminares.

    However as far as I can tell that is only legally relevant for private rented properties. Approved document P still says

    (and even approved document P is not law, merely government guidance as to one way you could comply with the law)

    What you do or don't do in your house is your decision, but personally if it was my house I wouldn't be worrying about RCD protection for additions to the lighting circuit.
     
    Last edited: 20 Apr 2021
  14. AndyPRK

    AndyPRK

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    Which nice British you tuber ?
     
  15. TimboTwo

    TimboTwo

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    It might be possible to move the lighting mcb(s) across to the rcd side of the board.
    Depending on what's under the cover.
     
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