Outside light from a spur socket

Discussion in 'Electrics UK' started by Sam78263, 11 Nov 2021.

  1. Sam78263

    Sam78263

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    Hello,

    I would like to fit an outside light, but the only power source nearby is a spur socket. If I add an FCU to the spur, will it be OK to then run sockets and outside light FCU from that?

    What I'm planning to do is (I also want to move the socket to the right):

    circuit.png

    Does that look correct? The sockets are RCD protected, and the switched 3A FCU would be double pole.

    Also, what cable would be appropriate to use from the 3A FCU to the light? It would be going through a cavity wall directly into the back of the light:

    outside-light.png

    Would 1.5mm2 T+E be suitable, or would something like 1.5mm2 NYY-J be better? Can NYY-J be chased into the wall? And is it OK to have the cable unprotected when going through the cavity wall or should it be in conduit?

    Thanks!
     
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  3. winston1

    winston1

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    No. You said your existing socket is a spur. You cannot have a spur off a spur on a ring circuit.
     
  4. sparkwright

    sparkwright

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    Yes. What you propose is fine.

    Winston is completely wrong.

    He states you cannot have a spur off a spur on a ring circuit.

    HOWEVER, as you have replaced the original spur socket to a FCU, it can therefore supply an unlimited number of sockets or more FCUs.
     
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  5. sparkwright

    sparkwright

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    Regular 1.5mm2 T+E would be ok between the light and it's FCU.

    You COULD put the cable in conduit where it passes through the wall, but to be honest no one bothers and it's more trouble than it's worth.
     
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  6. winston1

    winston1

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    Post 1 diagram clearly shows a spur off a spur off a 13a socket. There is no suggestion the 2nd spur is off the output of the first.
     
  7. winston1

    winston1

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    No need for 1.5mm cable. 1.0mm is more than adequate and easier to use.
     
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  8. sparkwright

    sparkwright

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    It DOESN'T.

    The original socket has been replaced with a 13amp unswitched fused connection unit.

    From the load side of this, there is:-
    one cable feeding a double socket
    one cable feeding a 3amp FCU for the outside light.

    Please look again.
     
    Last edited: 11 Nov 2021
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  9. winston1

    winston1

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    The original socket is still there. Then there is an unswitched FCU, and finally a switched FCU off that.
     
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  11. Sam78263

    Sam78263

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    Great. Thanks for your help!

    Maybe I should have made the diagram a bit clearer. I'm proposing to move the double socket to the right and putting a 13A FCU where it currently is with one cable from that going to the double socket and another cable from the 13A FCU going to the 3A FCU and then on to the light.
     
  12. sparkwright

    sparkwright

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    Is it buggery.

    Can't you see in the diagram the double socket only has one cable at it?

    Can't you see the cable feeding the socket in the very first diagram is now feeding the unswitched FCU?

    Can't you see in the first post he has written that he wants to move the socket to the right?
     
  13. sparkwright

    sparkwright

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    He's gone.
     
  14. winston1

    winston1

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    Not really that clear but never mind.
     
  15. scousespark

    scousespark

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    It's as clear as day.
     
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  16. RandomGrinch

    RandomGrinch

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    Hi,

    Ignore the bickering!

    I was slightly confused at first. But yes, as long as both your double socket and the switched FCU are fed from the "Load" side of the un-switched FCU, it should be fine!
    ...and I would run the cable in a conduit through the wall, with a slight downward gradient to the outside; allowing any cavity water seepage to escape to the outside, rather than forming a damp patch on the inner wall.

    Good luck! :)
     
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  17. JohnW2

    JohnW2

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    Clear enough (at least for me) to indicate who is right and who is wrong. In fact, I struggle to find anything even remotely 'unclear' about it.
     
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