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1.5mm² lighting cables - 3 lights- do they have to be in-line?

Discussion in 'Electrics UK' started by Dain1, 26 Jun 2019.

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  1. Dain1

    Dain1

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    3 lights. It would be easier if the cable went to 1st light, with 2nd and 3rd light cables both spurred off from 1st light, in a Y formation. I could do it linear, but easier in a Y.

    What do regs allow?

    Thanks,

    Dain
     
    Last edited: 26 Jun 2019
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  3. JohnW2

    JohnW2

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    No problem with that.

    You don't really need 1.5mm² cable - 1.0mm² would be more than adequate.

    Kind Regards, John
     
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  4. Dain1

    Dain1

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    Thanks John. I have part roll of 1.5mm² that needs using, it's going in.
     
  5. JohnW2

    JohnW2

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    Fair enough.

    However, I should have added that, whilst your 'Y formation' is fine, electrically speaking, the one proviso is that it requires three, rather than two, conductors to go into each terminal in the first light, and some of those terminals can struggle to take 3 conductors. That's why I mentioned 1mm² cable, since it's obviously easier to get three of them into a terminal. However, if 3 x 1.5mm² ones will fit, that's fine.

    Kind Regards, John
     
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  6. Dain1

    Dain1

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    Certainly something to consider, thank you.
     
  7. seasickstevie

    seasickstevie

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    Likely to need four, rather than three.

    Live in, Live to '2nd' light, Live to '3rd' light, Live drop to switch.
     
  8. JohnW2

    JohnW2

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    Many light fittings don't have (at least, not 'built-in') provision for use as a 'rose' (i.e. with switch drop coming from the light) - but, even if they do, then if (as is very common) the fitting has a 'choc bloc' type connector, no terminal would have to accommodate more than 3 conductors ...

    upload_2019-6-27_1-3-8.png

    Kind Regards, John
     
  9. eta

    eta

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    isnt that switch running the other two lights as well like that , which is fine if the 3 lights are all switched from the same 1 switch
    otherwise if each light needs own switch - then 4 1.5mm cables needed in one junction OR terminal block above rose

    although three could go into other side of live if a chocblock arrangement where 2 ends have screws -
    NOT AN ELECTRICIAN
    rose i used to fit only has the one connector for each terminal
     
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  11. JohnW2

    JohnW2

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    Yep, that's what I had assumed (maybe wrongly) that the OP wanted.
    Indeed.
    Yes, roses have 'one-sided' connectors (although they have multiple, joined, ones - e.g. 3 for Ls), but light fittings often have a two-sided choc-bloc type of connector.

    Kind Regards, John
     
  12. seasickstevie

    seasickstevie

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    I had obviously assumed that they were three independently switched lights.
    If (like JW2 suggests) the 'loop In' is a separate connector block, there's obviously the opportunity of just two into each side.

    There still is likely four CPCs (with the switch being the fourth - which JW2 hasn't shown), but they'll be 1mm regardless.
     
    Last edited: 27 Jun 2019
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  13. JohnW2

    JohnW2

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    Yes, I overlooked that. In fact, if the connector were 'one sided' (like a standard rose), there would be 5 CPCs all going into 'one hole' (but, as you say, thankfully only 1.0mm², even with 1.5mm² cable).

    Kind Regards, John
     
  14. seasickstevie

    seasickstevie

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    Can't help but feel that in this age of LED lamps pulling next-to-nothing, the use of 1.5 seems such over-kill.
     
  15. JohnW2

    JohnW2

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    I totally agree - but it seems to be a very well-established habit. Indeed, even 1.0mm² is substantial overkill (and would usually still be be even with a 6A load).

    Kind Regards, John
     
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  16. Dain1

    Dain1

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    Ok, I'll just do in-line.

    I have 1.5mm² cable going begging and there's no plasterboard ceiling up yet. Progress is what I'm after here.
     
  17. JohnW2

    JohnW2

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    Fair enough - but the only reason for having to do that would be if it were the case that (with whatever cable size you were using) you could not comfortably get the required number of conductors for the "Y arrangement" into the terminals of the light fittings.

    Kind Regards, John
     
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