junction box in loft

[JohnW2]

Picture attached. Incidentally, I have seen another switch on the same floor with one cable going to COM and another going to L1: there is no third one as in this picture. I haven't seen any kind of junction box in there before, so if such a thing would be any kind of size, then I doubt there is one.

There probably isn't any junction box. It now appears that the Neutral is probably 'looped' through the ceiling roses and that the line/live is 'looped' through the switches. That probably means that the only place you'll find the end of a permanent live (to facilitate the loft lights working without having to switch another light on) would be at a switch. However, assuming that the cables go upwards from the switches, you might well be able to 'intercept' one of the permanent lives in the loft and insert a junction box to provide you with access to a permanent live.

Kind Regards, John

 

[wrathkeg]

.

 

[Taylortwocities]

It now appears that the Neutral is 'looped' through the ceiling roses and that the line/live is looped through the switches.

Ahh yes, could be.
I have never seen it done like that before. Must get out more!

 

[wrathkeg]

Thanks. I believe that the cables go up from the switches into the loft. When I get the chance, and a protective mask, I will see if I can find a permanent live from a switch near a neutral to put in a junction box for the new lights.

 

[Taylortwocities]

Cool, Don't forget you will need an earth too.

I would want to test that JohnW's assumption is correct, before you do too much.
You'll need a voltage test device to do this, you'll need it to check which red is the right one too!

 

[JohnW2]

Thanks. I believe that the cables go up from the switches into the loft. When I get the chance, and a protective mask, I will see if I can find a permanent live from a switch near a neutral to put in a junction box for the new lights.

Yes, as I said, if my assumption is correct then I think that should be possible, and possibly quite easy. If you can find the three red wires coming from one of the switches, two of them should be permanent lives and the third one a switched live for the light in question - so it would only be a matter of finding out which was which.

Edit ... P.S. as for whether my assumption is correct, if that light switch you've shown us is working just one light, then my assumption is very probably correct. The only other explanation for the two joined red wires would be if they were supplying two separate lights, but I doubt that is the case.

Kind Regards, John

 

[wrathkeg]

By memory, I think the cables from one of the switches emerge near to the loft hatch so I may be able to use that, along with the neutral going to a nearby light.

And yes, that switch controls just one light.

 

[mwatsonxx]

Is this place up north? Never seen anything like this, but I believe there is a major regs contravention. The earth wire (cpc) is under sized for an unprotected conductor, it should be a minmum 4mm². I suggest you get a good spark to carry out an inspection

 

[winston1]

Ahh yes, could be.
I have never seen it done like that before. Must get out more!

It was very common in the '30s, with conduit forming the CPC. It is quite possible in a subsequent rewire just the wires were replaced.

 

[winston1]

Is this place up north? Never seen anything like this, but I believe there is a major regs contravention. The earth wire (cpc) is under sized for an unprotected conductor, it should be a minmum 4mm². I suggest you get a good spark to carry out an inspection

I know it is the rules but why should a bare earth wire need to larger than an insulated one buried in twin and earth? The insulation insulates heat as well as electricity after all.

 

[Taylortwocities]

I expect that it met the regs at the time of installation. And regs aren't retrospective.

 

[JohnW2]

I know it is the rules but why should a bare earth wire need to larger than an insulated one buried in twin and earth? The insulation insulates heat as well as electricity after all.

It's single-insulated, not bare. We've discussed this before, and the conclusion has usually been that the requirement for a CPC which is not within a multicore cable to have a CSA of at least 4mm² must be related to mechanical integrity (since the alternative is for it to have 'mechanical protection). I'm not sure without looking, but I'm not convinced that, provided the CSA is compliant, the regs actually require any insulation of a single CPC at all.

Of course, even if there is additional 'mechanical protection', there is still a requirement that a single CPC has a minimum CSA of 2.5mm². That is less easy to understand, given that 2.5mm² is greater than the CPCs in 1mm², 1.5mm², 2.5mm² and 4mm² T+E.

Kind Regards, John

 

[Risteard]

But if it was compliant with the regs at the time of installation then it's OK.

Not true. If it is safe then it is OK. It is completely and utterly irrelevant whether it complied at the time of installation or not.

I have seen in another picture now that there is also no protection against abrasion for the cables entering a galvanised backbox. It is also unclear where the cpc is originating from.

Insisting upon periodic inspection and testing of the installation is indeed the only correct advice as I have stated. It is also a requirement of BS7671 for every installation - not just this one.

 

[Risteard]

And regs aren't retrospective.

Except when they are.

Fused neutrals are illegal. They were once permitted, ergo the Regulations are indeed retrospective.

 

[Risteard]

Is this place up north? Never seen anything like this, but I believe there is a major regs contravention. The earth wire (cpc) is under sized for an unprotected conductor, it should be a minmum 4mm². I suggest you get a good spark to carry out an inspection

Indeed, all of which I stated earlier but unfortunately others here do not believe that it is sensible advice. However I know for a fact that your advice is correct, and you know for a fact that my advice is correct.

The others have opinions which are wholly incorrect.