Anyone help me with the regs on these? They are fitted over standard switches and so there is no way of earthing them separately. Seller claims they are fine if fitted over switches with earthed metal backboxes but doesn't that mean they are only earthed through the screws which I have read doesn't meet the current regs.
Chrome Cover Plates over plastic switch plates
- Thread starter DrMopp
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There are nylon screws.
If they are being fitted over something which is already 'safe to touch', there is surely no need for them to be earthed, is there?
Kind Regards, John
But that wouldn't help to earth the chrome plate though.
Might prove useful if there was no earth in the circuit, but I'm fairly sure these plates are supposed to be earthed through the screws.
Would like to think a chrome plate over a plastic switch could be considered Class 2, and perhaps the nylon screws would achieve this, though I suspect not if the manufacturers instructions are to be believed.
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As I've said, if the switch were plastic and hence already deemed to be safe to touch (even if not formally called/labelled 'Class II', I see no reason why there is any need for metal outside of it to be earthed.
Are you not happy with touchable metal screws being used to attach a plastic accessory to a (plastic, hence not earthed) plasterboard box?
Kind Regards, John
No, but it will prevent it becoming live.
Not if they are not exposed-c-ps - better to be isolated and not earthed.
It doesn't matter what the manufacturer says.
From the different opinions on here it seems I have two options, leave as is (earthed via screws) or fit nylon screws (@EFLImpudence - do the nylon screws you mention have white heads?). Anyone here know of 'chrome effect' but plastic switches?
Would nylon screws not cause a lot of effort in trying to get them to match?
Would it not be best to go along with the manufacturers instructions on this occasion, if only to help to make a decision?
The nearest example of something similar which electricians would do without question is this:-
On an (outdoor typically) galvanised earthed round conduit box, one would fit a rubber gasket, then the round galv lid, with brass screws.
If you can do that without question, one would presumably be best off using metal screws for the light switch plate in question, assuming the back box is definitely earthed.
Would it not be best to go along with the manufacturers instructions on this occasion, if only to help to make a decision?
The nearest example of something similar which electricians would do without question is this:-
On an (outdoor typically) galvanised earthed round conduit box, one would fit a rubber gasket, then the round galv lid, with brass screws.
If you can do that without question, one would presumably be best off using metal screws for the light switch plate in question, assuming the back box is definitely earthed.
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Not saying there aren't any on the market, but I have never seen them.
The screws will be white.
Look, earthing is not a good thing for its own sake; it is a necessary evil so that if a live wire contacts a touchable metal part and makes it live, this will cause a fault which will cause the fuse/circuit breaker to disconnect the power (instantly) before anyone has a chance to touch it.
As these switch covers cannot contact a live wire they do not actually require earthing (they are not what we call an exposed-conductive-part).
If you use metal screws with a good contact, then the cover will be earthed, so, in the event of a fault within the earthed back box, they will become live for the very short time until the power is disconnected; the same as if the switch itself had a metal front.
It isn't likely but if the screws do not make contact with the cover then it will not be earthed but that doesn't matter.
.... but ...
Quite so.
As I have written at least twice, I really don't understand why we are talking about the unnecessarily earthing of something that doesn't need to be earthed (since, as you, EFLI, say, it's not an exposed-c-p).
In addition to what you say, unnecessarily earthing anything theoretically slightly increases the chances of electric shocks since, if one happens to touch something else nearby which is live, the unnecessary earthing provides an extra opportunity to simultaneously touch something earthed - hence an electric shock.
I probably wouldn't worry (since the risk is incredibly small) but, if I wanted to make things 'as safe as conceivably possible', I would probably use nylon screws, so that the cover was definitely NOT earthed.
Kind Regards, John
Yes, agreed, but DrMopp (along with others) seems to think that the subsequent unavoidable earthing of the cover by the metal screws might somehow be 'not good enough' and not meet the current regulations.
Yes, I realise that, but, as you will understand, I have been trying to explain (as have you) that not only is there no regulatory requirement for the earthing but that to unnecessarily earth the cover would, at least theoretically, slightly increase 'danger'.
If the regulations wanted to be 'ultra-cautious', I suppose they could 'ban' the unnecessary earthing of things. I would imagine that very few electric shocks result from people simultaneously touching L and N, so that, in practice, the less touchable earthed metal there is around, the lower the risk of electric shocks.
Kind Regards, John
@EFLImpudence, I don't 'seem to think' anything of the sort, I came here to ask, from a position of ignorance, if the fitting met the regulations, as I had read (on an electricians forum) to the contrary. It would seem the short answer is that there are as many opinions as there are electricians!
Sorry for trying to help by giving you the correct explanation.
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