Earthing a light fitting in a non-earthed lighting circuit

Joined
18 Apr 2014
Messages
4
Reaction score
0
Location
Bristol
Country
United Kingdom
Hi there. My house needs re-wiring, and I'm planning to get this done (by a professional) in a year or two. In the meantime, I would like to put up a light fitting that needs an earth connection.

Problem is, my lighting circuits are not earthed.

Would it be safe / acceptable / hideously dangerous to put a JB into a nearby 13A ring main and take an earthing wire from that up to the ceiling rose? The house currently seems to have PME and all the earthing connections are commoned beside the main fuse. As an alternative, could I run an earth wire from the fuse commoning block up to the ceiling rose? Or are both alternatives no-go?

I am a (lapsed) electrical engineer, but have no training in house electrics, so I understand the general principles but not the details and I can carry out work to a competent standard. But some expert opinion would be most welcome.
 
Sponsored Links
This has been talked about many times. The cables should all follow the same route and if the wire is not part of a cable then minimum thickness is 4mm so in real terms putting in earth wires is as much work and running new cables and very hard to get a 4mm cable into earth connections of a light fitting.

What is an option is to wire a light from the ring using a switched fused connection unit (FCU) to reduce the maximum current. However new cables buried in a wall would need RCD protection.

So in real terms the only option is to use Class II fittings.

You have to accept the rules changed in the 1960's and houses should be inspected at least every 10 years so owners should have been aware of the problem for at least 40 years which is clearly enough time to get it corrected.

Although you can leave wiring which conformed to a previous edition of BS7671 there is not need to upgrade unless something new is added the first edition of BS7671 was in 1992 so clearly lights without earth do not comply with a previous edition of BS7671.

As to IEE wiring regulations the previous edition to 17th will be clearly the 16th but it was 13th edition which allowed lights without earths so rather stretching is some what clearly you can't today still use premises which complied to 1st Edition (1882).

The Electrical Safety Council does give guidance to what should be done where there are no earths to the lights personally I would say re-wire as you have had long enough but they say you can use Class II lights with Class II switches however it would need either plastic back boxes or bungs which cover the screw holes needs to be a tight fit so a tool is required to remove the bung.

So put it simple if fitting required an earth you can't use it.
 
Thank you for that comprehensive, if damning, response! I did look to see if the topic was already mentioned, but couldn't see anything recent.

I inherited the house from my Father three months ago, and the wiring is positively ancient, if not downright dangerous. It frightens me! So yes: a full rewire is on the cards once funds can stretch to it.

I guess the fitting's going back to B&Q then.
 
Got the same problem with my Mothers house my dad would not let me re-wire it said he did not want to live in a building site and my mother does not use much power except for kitchen which has been re-wired so when she goes it will need a re-wire.

I hope by time that happens my son can help with re-wire. Told originally had 5 sockets so much better than my Grand dads house with just 2 sockets they were over the moon with 5 and new 13A not 15A like grand dads.

But my dad has taken spur off spur off spur and before a normal family can use the house it will need full rewire except for kitchen.
 
Sponsored Links
I've just put a basic white plastic pendant up where the fancy dancy fitting was intended to go and... Oh sheesh. Porcelain ceiling rose with a wooden base, solid core wires, crumbly insulation so discoloured I couldn't tell which was supposed to be red and which black. And the house circuit breakers were a little worrying: everything except the main breaker turned off, and the lights were still working.

At least when the place does get done I'll have a few antique light fittings and bakelite switches to eBay. Purely as non-functional ornaments, you understand...
 
What is an option is to wire a light from the ring using a switched fused connection unit (FCU) to reduce the maximum current. However new cables buried in a wall would need RCD protection.

easily provided with an RCD FCU



CM4904XXX.JPG
 
Thanks for that Owain, but having seen the state of the wiring close up I've decided to make do until the whole system can be replaced. I really don't want to disturb things any more than I absolutely have to.
 

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.


Are you a trade or supplier? You can create your listing free at DIYnot Local

 
Back
Top