Lighting cpc's cut off!

[Tuttle]

I've done a CU change in a house where there's been some DIY work resulting in lots of the cpc's in the lighting circuits being cut off! I think that the owner of the house was under the impression that cpc's are not required for lighting circuits and so simply cut them flush with the sheath of the T&E. Luckily, the remainder of the wiring in the house tests ok (after a some minor remedial work here and there).

I managed to crimp and reconnect cpc's in some of the light fittings and light switches, and also connect some parts of the lighting circuit that haven't been fiddled with to the cpc of a nearby socket on the ring (not ideal I know) resulting in all the class I light fittings in the house being earthed. The house has been recently decorated, floorboards covered with hardboard before gluing down new carpets, making it impossible to reconnect cpc's in junction boxes under the floor.

What I am left with is plastic ceiling roses and plastic light switches with no connection to earth, which seems acceptable to me. The only problem is that the light switches have metal back boxes and metal screws, which seems bad to me, and some may be connected to the cpc conductor in the cable which is not earthed, which just makes matters worse.

So, what's the best way of dealing with this? I'm thinking of going back and either replacing the metal screws with white nylon screws (which seem difficult to source) or getting some switches with little plastic caps over the screws. I think their current switches are MK and I assume there's not an easy way of covering screws on these?

 

[Marvo]

You say you've extended some but can't you extend all the CPC's that have been cut off either with ferrules or solder? I'm not keen on the idea of using a socket circuit cpc to earth a lighting circuit to be honest.

 

[Guest55]

a quick easy temporary fix may be to cover the screw heads with a small blob of white silicon neatly smoothed over flush with the switch plate , it will be un-noticable unless you look closely.

 

[Octopus]

or leave as is and put a note on the cert.

tin hat on.

 

[Tuttle]

You say you've extended some but can't you extend all the CPC's that have been cut off either with ferrules or solder? I'm not keen on the idea of using a socket circuit cpc to earth a lighting circuit to be honest.

No, I can't extend them because I can't get to them. The sheaths and cpc's have been cut back too far and there are only line and neutral conductors sticking out of the ceiling. Where there is enough slack in the cable I have been able to pull the cable through to get to the cpc, but some cables have little or no slack in them.

There are also junction boxes under the floor and it's a three story house with a flat roof and therefore no loft.

The cpc's on the top floor were mostly connected together but not earthed, due to the problems on the floor below, and it was these cpc's that I connect to the ring circuit.

 

[telectrix]

blob of silicon on switch plate screws.

 

[Guest55]

blob of silicon on switch plate screws.

genuis !
wish i'd have thought of that.
:-D

 

[telectrix]

click switches and bg nexus i think) come with little plastic cover plugs for the screws

 

[Guitarist]

Click switches with plastic caps are nice and cheap, plus a sticker inside the backbox stating that no metal accessories to be connected at that point.

 

[skamuk]

But what if the home-owner decides they want a metal dimmer switch next year?

 

[skamuk]

plus a sticker inside the backbox stating that no metal accessories to be connected at that point.

...Ah just saw that.

 

[shagbite]

have you thought about piping a bit of silicon into the holes where the screws are?

 

[skamuk]

Is there no plastic equivalent of the metal flush box anywhere? Or even use a plastic surface box in its place?

 

[kingeri]

You could put a blob of silicon over the screws. Haha.

Seriously, I've encountered this more than a few times. Had a similar issue on a socket radial recently, the CPC had broken off, no slack at all to pull up. Sods law it was the first socket on the circuit, and the supply side CPC had broken off, leaving the whole circuit unearthed. I scratched my head for a bit but ended up redirecting the supply to the socket that was the last on the circuit, so the offending socket then became the last one. Problem solved, just with a bit of logical thinking.

 

[Tuttle]

Actually, I'm not sure he's going to let me do anything at all. I couldn't persuade him that his unearthed class I light fittings were potentially dangerous. He just said things like "I never touch them anyway so it won't be a problem" or "it's been like that for years and I've never had a problem" or "I can even change the bulbs without touching the metal fittings". They're not exactly high up, you'd bump your head on them if you were very tall. Luckily it was an easy fix though, so I didn't have to argue for too long, and I did it before the CU change. I'm sure he wouldn't agree to silicon on the screw heads now though.

I think that I might have to write him a letter saying that he needs to arrange for the cpc's to be reconnected as soon as possible and that in the mean time he should ensure, as a matter of urgency, that the screws on the light switches are insulated, that no class I fittings are installed and offer to help him with this if he wants me to. I'm not sure if a letter would cover me if someone received a shock later though, but I hope that it would. It's difficult when they wont let you help them, what can you do? I've left the installation in a safer condition than I found it in anyway.