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

[Draughtsman]

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

 

[JohnW2]

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

No problem with that.

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

Kind Regards, John

 

[Draughtsman]

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

 

[JohnW2]

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

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

 

[Draughtsman]

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

Certainly something to consider, thank you.

 

[seasickstevie]

... 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.

Likely to need four, rather than three.

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

 

[JohnW2]

Likely to need four, rather than three. Live in, Live to '2nd' light, Live to '3rd' light, Live drop to switch.

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 ...

Kind Regards, John

 

[ETAF]

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

 

[JohnW2]

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 ...

Yep, that's what I had assumed (maybe wrongly) that the OP wanted.

... 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 -

Indeed.

... rose i used to fit only has the one connector for each terminal

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

 

[seasickstevie]

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.

 

[JohnW2]

There still is likely four CPCs (with the switch being the fourth - which JW2 hasn't shown), but they'll be 1mm regardless.

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

 

[seasickstevie]

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.

 

[JohnW2]

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.

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

 

[Draughtsman]

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.

 

[JohnW2]

Ok, I'll just do in-line.

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