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Continuous electric from lighting circuit to fused spur?

Discussion in 'Electrics UK' started by Minime46, 6 Mar 2020.

  1. Minime46

    Minime46

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    Hi all.

    So how do we find which cable on a lighting circuit has the live feed all the time and not just when a switch is on... or off?

    I found where the feed for the switch was, there were 2 cables going down to it... I did 1 and it turned off when the light was switched on... I then did it on the other one and it works perfect....

    But how to know which cable to cut/use and know there will always be power to it?????

    Hope someone can shed some light
     
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  3. terryplumb

    terryplumb

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    By testing ,multimeter or two probe voltage tester.
     
  4. winston1

    winston1

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    You don’t need a fused spur on the lighting circuit. What are you hoping to feed off it? A 3a fuse will have no discrimination against a 6a MCB.

    But as above you need to test it. Even a neon screwdriver will do. (Many electricians don’t like them but they are OK if you understand their limitations),
     
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  5. bernardgreen

    bernardgreen

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    Help the OP by explaining what those limitations are. Otherwise he may have an accident if he relies on a neon screwdriver for his safety.
     
  6. bernardgreen

    bernardgreen

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    Stupid error deleted.
     
    Last edited: 6 Mar 2020
  7. terryplumb

    terryplumb

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    It's in the thread title Bernard
     
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  8. bernardgreen

    bernardgreen

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    OOoops My errror. Sorry Winston1
     
  9. Minime46

    Minime46

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    I tried to use an electric pen sensor. Tried to touch on cable for lights after the switch it beeps ever second or so... so was not right. On continuous feed cable I thought it would just stay red... but turns out I first wired up to 1 of 2 cables coming out of a light switch... both said were continuously live with or without the light on... but once I wired it, when the light was switched on the power went off on my spur?!?

    (Its a spur and then alarm panel)
     
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  11. foxhole

    foxhole

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    Seems to be trying to take spur from light switch wiring ? Not possible unless the ring run thru switch but unlikely give description .
     
  12. Minime46

    Minime46

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    So how do I find where I am meant to spur from?
     
  13. terryplumb

    terryplumb

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    Is there any neutral conductors within the light switch enclosure ,maybe in a terminal block ?
    If you are using a non contact voltage sensor they are not the most reliable or accurate. You would need a multimeter or a two probe voltage tester ,and the knowledge of how to safely use them on a live circuit ,to determine what you need to know,with regard to what the various conductors are / what voltages are present.
     
  14. foxhole

    foxhole

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    Nearest light ceiling fitting or cable running into it.
     
  15. Minime46

    Minime46

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    I did this with one of the spots in the bedroom. There are 4 spots and a pendant all on 1 switch.

    I wired into the spot with the other cables but it would only work when the lights were switched on... annoyingly
     
  16. Keithmac

    Keithmac

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    Get an electrician in..
     
  17. ajohn

    ajohn

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    The question what are you spuring to and for what might clear things up a bit. So OP?
     
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