Earthing wall lights

I have replaced the wall lights in an upstairs room in my house. The new wall lights need to be earthed. Fortunately the supply is via a twin and earth cable where the earth was shortened and taped up.

I have enough leeway to use the earth in the supply cable, so my question related to where to earth these lights to.

In the loft I have water tanks with copper pipe down as far as the ground floor stop c*ck where the pipes go out of sight.

Should I get an earth strap and earth these lights to the incoming water supply pipe, or do the regulations / best practice say I should do something else.

Many thanks

Phil

Reply to
Aardvark
Loading thread data ...

In message , Aardvark writes

No.

You use the earth in the cable - that it what it is for.

Just connect them up to the earth in the cable. I am assuming here that the earth in the lighting circuit is all connected up properly back to the consumer unit.

Reply to
chris French

Best way is to find the most convenient socket which has an earth to it and bond it there.

Relying on water pipes is not ideal because however unlikely it may seem a plumber (or whoever) could disconnect the pipe and thus break the bond.

Using the incoming water mains as the bonding (earthing) point went out a while back. Bonding arrangements using pipework is used for something called equipotential bonding - to keep all the pipework at the same potential (voltage if you will), and that might not necessarily be ground.

The ideal situation would be to run the earth back to the consumer unit. If you do run an earth wire any distance it's best to make it a fair size (4mm or better).

Andrew

Reply to
Andrew McKay

When I bought my house some 20 years ago I noticed that two (metallic) wall lights in the living(!) room were wired with 2-core flex buried diagonally in the wall directly from the back of a pair of 13A sockets as a spur from a 30A ring main...

Needless to say these lamps have long gone! Frank Erskine OETKBC

Reply to
Frank Erskine

In message , Frank Erskine writes

Creepy!!!!!!! I had exactly the same 10 years ago. The 9KW shower was also wired with

2.5mm T&E via a 13A fused spur. Only noticed the shower wiring after a couple of weeks when the 13A fuse blew. There was such a volts drop in the cable that the fuse mustn't have been too much over its rating, nice warm wall though!
Reply to
Bill

Until someone decides to rip out that socket.

Reply to
Rob Morley

Thanks for the replies. I have some follow-up questions.

One poster said to tie my earthing requirements back into the main earthing system.

The cabling we are talking about here is all in the loft of the house and I do not recall seeing any earthing cabling up in the loft at all. The lighting circuits do not have any earth wires and there are no power sockets in the loft. Only a single lighting circuit.

Should I look further for an earting system up there. This is a

1930's house with a wiring system from that era, although most cables are of the newer (white PVC) type I suspect the wiring layout design is of the 1930 era.
Reply to
Philip

In message , Philip writes

Well you wouldn't normally see any separate earth conductors.

So you mean the cable that supplies the wall light points has an earth conductor, but the circuit that it connects to presumably predates this and does not have one?

In that case you need to add one back to the consumer unit. I don't know if connecting to the earth on another circuit is allowable, but I certainly wouldn't want to do it. While you could add a separate earth cable back to it as suggested, I would look into rewiring the lighting circuit with T&E (you could do this in bits as you decorate)

I would certainly want to check over the whole system

We have a '30's semi, partly rewired in the 1960's. If our experience is anything to go by you will end up rewiring the lot eventually anyway. Lighting circuits won't have an earth, there won't be enough sockets - don't assume a sensible ring main, ours was a total hotpotch of a a ring but most of the sockets were pond various spurs all over the place.

I would want to check that there is no of the original probably 1930's rubber cable - if so you want to get rid of it ASAP (look carefully, some of our switches had PVC cable that connected to the original rubber cables buried in the wall behind the switch)

Reply to
chris French

That makes the lighting wiring rather old - although if PVC could still be ok.

Don't think very much has changed in design, really.

If the wiring is as easy to get at as you suggest, I'd be tempted to replace the lot with TW&E. Bodging an earth on here and there just as absolutely necessary isn't good practice.

Reply to
Dave Plowman (News)

" The lighting circuits do not have any earth wires"

If this is the case then you really need to be replacing the circuit with modern cable.

You can then earth the wall lights through this

Will

Reply to
gribblechips

Unless the circuit is RCD protected (unlikely), Reg. 544-01-01 will apply and dictates that the CPC (circuit earth) must be "incorporated in the same wiring system as the live conductors or in their immediate proximity."

So "no" is the probable answer, but a 'borrowed' earth (as a temporary measure) is better than no earth.

Yours too! 1930s usually means cotton-covered VIR in conduit. Given the OP's obvious lack of knowledge here an inspection and probably a complete re-wire by a competent person would seem to be indicated.

Reply to
Andy Wade

This sounds confused. It is important to establish if there is any 30s wiring still in use. If there is, it will be a real fire risk by now.

PVC with red black and bare copper conductors is modern, more or less. PVC with red and black, but no 3rd conductor, is an old wiring system, but certainly not 30s. If you find electric cable covered with lead, woven cotton, or rubber, its time to be genuinely concerned (likely

1930s) and plan on rewiring as quick as poss. If you find cable covered with treated paper, stringy rag material, or bare steel wires strung between ceramic knobs, its time to panic.

NT

Reply to
N. Thornton

HomeOwnersHub website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.