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Video doorbell power supply

Discussion in 'Electrics UK' started by RobTi, 18 Aug 2021.

  1. RobTi

    RobTi

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    Hi just wondered can I take power from the lighting circuit, I have no power at the door and no way to get it but wondered if I could take power from the light circuit and use that. I was thinking taking a L,N&e from the live @ the light switch up to ceiling level install a switch/breaker of some sort along with a transformer and then drop the cables back down to the doorbell. Yes or no ?
    Thanks
     
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  3. bernardgreen

    bernardgreen

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    How many wires do you have at the light switch ?

    Are there
    (1) A Brown and a Blue both to the switch
    or are there
    (2) Two Browns to the Switch and two Blues to a terminal block.

    If (1) then there is no Neutral at the switch, the Blue is the Switched Live

    If (2) then most likely the two Blues in the terminal block are Neutral and one of the Browns is Live and the other Brown is Switched Live
     
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  4. RobTi

    RobTi

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    Just finished dropping a new 3core and earth from ceiling down to switch so have a live and neutral there
     
  5. oldbutnotdead

    oldbutnotdead

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    You may or may not have neutral at the switch- depends how the circuit has been wired. You will almost certainly have permanent live and neutral at the light fitting...beaten by @bernardgreen .

    Whichever of the 2 scenarios you have, yes you can power your transformer from the lighting circuit. It's a good idea to use an FCU to make the connection to the transformer (make sure it's a double pole switch type, put a 3A fuse in it, mark it so the next person knows it's on the lighting circuit), then bit of 2 core flex to your doorbell and off you go.
     
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  6. winston1

    winston1

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    A FCU is not required on a lighting circuit as a 3 amp fuse has no discrimination against a 6a MCB. Put a switch if you like (you will never use it).
     
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  8. bernardgreen

    bernardgreen

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    Good advice, a failed transformer that trips the RCD and puts the lights out is quickly and easily isolated by a double pole switch thus allowing the RCD to be reset and the lights restored
     
  9. oldbutnotdead

    oldbutnotdead

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    Fair point re the fuse long as the lighting circuit is 6A, it was more the dp isolation can be handy if the PSU/transformer melts.
     
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  10. RobTi

    RobTi

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    Thanks to everyone for the helpful replies will follow your advice when I decide to proceed
     
  11. winston1

    winston1

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    Double pole switches (without fuses) are available. Never known a bell transformer to fail or melt.
     
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