I've discovered that the wiring to a light switch is in 2 core (i.e. no earth) so the metal back box was unearthed. Getting an earth to it would be a royal pain so I've removed the metal back box and plan to sink a surface box so the back of the switch is in an insulated enclosure and there's no chance of the screws making contact with a live wire if a wire broke. What's the opinion of the jury? Any alternative solutions?
Unless you know of a good reason why the earth has not been installed, I would treat the discovery as an invitation for a full wiring inspection.
AB
And after a full and legal trial the only option in most cases is a rewire.
Earthing of lighting circuits became a requirement in 1966.
Get some plastic screws instead? If you really are that concerned. But don't use any type of metal plate switch or dimmer that must be earthed.
Not really - wiring from the time when an earth on lighting circuits wasn't mandatory could well be still in perfect condition.
Yes, but if the wiring is sound there's no need for a re-wire. As I slowly go through the rooms (it's not a small house) I'm sorting out the problems as I find them. I've just found a better solution to this particular problem. There's a light switch in the adjacent room, almost exactly behind the switch that's bothering me, and this has an earth. They are on the same lighting circuit so an earth wire through the wall and all is well.
I've just found a better solution to this particular problem. There's a light switch in the adjacent room, almost exactly behind the switch that's bothering me, and this has an earth. They are on the same lighting circuit so an earth wire through the wall and all is well.
I wanted to solve the problem rather than masking it with plastic screws that someone might replace in the future.
Does it go anywhere :-P
Do check the earth is connected to earth, though. In the days when earths weren't mandatory but TW&E was around, you'd often fine it connected at one end, but not the other...
If you are concerned about what future owners (or whatever) might do, best get absolutely everything checked out and up to the latest spec. ;-)
Unless of course it's old enough to have been installed before earth/CPC was required for lighting.
Are you / have you upgraded the CU with a 17th edition / all RCBO style setup? If so, then the addition of a suitable warning label would be adequate IMHO.
See the section on reducing risk here:
A very good point, but I had checked and there *is* continuity.
It's been the plan to change the CU for the last 12 months, first it was too cold in the roof space, then I was too busy, then it was too hot, now I'm too busy, soon it will be too cold. I need to man-up! :-)
I don't think it will be fully RCBO because there are lots of circuits and (when I last looked) RCBOs are still quite expensive. Ref earlier discussions, several things can be combined onto a single RCD so there will be a mix of RCBOs and RCD+(n)MCBs.
Yes (fortunately)
The thrust of what I was getting at was if the lighting circuit in question ends up with RCD protection at <= 30mA trip threshold, then you can "get away" with proper labelling and making sure no Class I switches and luminaires are in use. Its not as "good" a solution as a re-wire, but sometimes that is not realistic.
Chuckle, I well recall a strange thing before this house was rewired in the
70s, when stripping off some wallpaper somebody had earthed a box by a piece of copper tap up the wall to a copper water pip. This was located in between floors. Highly dodgy, but then things of this kind were done back in the 60s and before I'm sure. BrianHmm, well good, I think. However I remember my Dad back in the 50s making his own wall lights with two core just buried a tiny bit in the plaster of the back room walls and the lights were made of hardboard with a toggle switch of the kind that used to be fitted to radios, ie the solderable kind with a metal toggle. I always did get a tingle off of those but I'm still here! Brian
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