No Earthing on Lighting

[Doc Hudson]

BS7671 Regulation 543.1.2 allows for two or more circuits to share CPCs.

However it does go on to say that it may need to be a larger C.S.A. to provide protection for all circuits connected, which may not be sufficient in Matty's case?

Doc H.

 

[sparky b]

If they're really that concerned about the decoration, why not run swa on the outside of the property, then you can put them on their own circuit...

 

[spinlondon]

However it does go on to say that it may need to be a larger C.S.A. to provide protection for all circuits connected, which may not be sufficient in Matty's case?Doc H.

No actually it doesn't.

 

[M107]

Why not run new supply (L N & E) for upstairs lighting external to the property in conduit, dropping into the loft from under the soffit.

That way you get a cpc up in the loft & all thats needed then is to run 1.5mm single around loft to lighting points.

If you cant get cpc down to switches, change plate screws for nylon screws & remove any metal switches & note deviation on cert & at DB.

Or as others have said run new circuits for extension, it has been known for a submain to go in & a seperate DB to be located in the extension

 

[PIP IOM]

I know this is probably going to get slated but here we go. Why not spur down from whatever socket supply circuit that you are using, i know that I've done it in the past and advised the customer that the circuits that have no CPC should ideally be rewired.

 

[M107]

I know this is probably going to get slated but here we go. Why not spur down from whatever socket supply circuit that you are using, i know that I've done it in the past and advised the customer that the circuits that have no CPC should ideally be rewired.

Nothing wrong with that option, but on an extension thats a lot of lights up & down (if it is 2 storey) off fcu's & not that professional. But yes we've all done it, I do in conservatories & out buildings.

 

[fletchflash]

In your original post you said you'd tested between L-E and there was nothing there?

Does this mean the cable has a CPC but is not connected to earth due to a fault/previous bad workmanship?

If so then surely its worth trying to fault find? theres always a JB with loads of twisted together earths that have snapped. try looking under landing.

otherwise, as previous mentioned I'd run a new circuit to board, as tidely as possible! Use trunking and decorators caulk?

Its a bit unrealistic to start using SWA pricewise just to do some extension lights.

Could you not spur from a power circuit? Not ideal but acceptable.

Good luck mate, sounds like a bit of a nightmare but i imigine you probably same as me, cant afford to walk off jobs!!

 

[Lurch]

Rewire, repair or walk away.

Bodging it in with an earth from somewhere else is way beyond a last resort IMO. The regs may state ways that you can get around the bodging side of it but I don;t think any of them are really necessary as the replace or repair option should be easier, or then there's the walk away option. I can see what people are saying about the can;t afford to walk away thing, but bodging an earth in one light fitting, are things really that bad?

 

[ProDave]

You are all looking at this from the wrong angle.

You mention the existing lighting junction box is wired with t&e cable, but you get no continuity to the CPC.

Your "solution" seems to be add an earth.

But surely, as it's wired in t&e, should you not be looking for the "fault" i.e looking for the break in the existing CPC? Almost certainly where the feed loops in either a switch, or light fitting or another junction box perhaps?

EDIT: Actually already suggested in post #27

 

[Andy™]

finding the fault would probably be easier. surely you can easier identify which cable has lost the earth, and then repair it. as already mentioned, its most likely a dodgy connect at an accessory or JB

 

[SPECIAL LOCATION]

As others have said need to verify 2 options:-

1/ The circuit does actually have a CPC leaving the fuse box.... but broken some where along route..

2/ No CPC leaving fusebox.. its old twin with no earth! (in which case should have been spotted at initial assessment of job!)

If 1. go hunt down the break, fix, continue with new additions jobs a goodun!

If 2. IMHO needs proper rewiring back to CU.

As has also been pointed out two circuits can share a common CPC..

But personally with final circuits wired in T&E I would expect each circuit to have its own CPC...

due to risk of one circuit being disconnected at a later date leaving another circuit without any CPC! :_|

A socket circuit & a light circuit run in metal conduit, when conduit forms the CPC for both circuits is a more acceptable use of common CPC IMHO..

i.e. alterations to one circuit will not break or remove the CPC to the other circuit.