T
Ah thanks. If it is, does a new cable go from the other side of the terminal block to that screw?
Light switch earthing
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I don't think we're really disagreeing -as I said,people doget struck by lightning,and some have probably been hit by meteorites. We're talking about probabilities -and it remains my belief that to get an appreciable shock by the process you describe is incredibly improbable. For that to happen, at least four things have to happen simultaneously:
1....The backbox has to become live. Although it happens, that, in itself, is extremely rare, and not something that I recall personally ever having encountered.
2...One has to touch the faceplate screw. The heads of such screw on plastic accessories are usually significantly recessed,such as one has to make a fairly determined effort to "push one's finger into it" before there is any contact.
3... There has to be something earthed close enough to the accessory to be simultaneously touchable. Looking around my house,that is true of only a very small proportion of the plastic accessories.
4.... IF there is something earthed close enough to be touched simultaneous with the screw, one actually has to touch the screw head - which one would not normally do during normal use of thee accessory.
I would say that each of those probabilities was extremely small, so that when one multiplies them together, I wouldn't expect one to be too far from the "struck by lightning" scenario.
Kind Regards, John
It it can happen then it will > Murphy`s Law (a.k.a Sod`s Law).
A few million tries on a regular basis and yes it will happen now and then.
Each one of us got born with improbable statistics
A few million tries on a regular basis and yes it will happen now and then.
Each one of us got born with improbable statistics
That last photo you have shown in response 26 is a real and serious concern. 2 live wires (switched or otherwise) have been 'joined' together, covered in tape and then one of them inserted into the switch. There is visual evidence of some other wire being wrapped in tape. There also appears to be a small loop of bare copper appearing at the bottom of the photograph. Whoever did that wiring could not be called a competent or responsible 'electrician'
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Indeed so - just as with lightning and meteorites
.... but even more so with driving cars, crossing roads, using ladders, power tools or kitchen equipment (etc. etc.), or even going up/down stairs or getting out of bed!
... and if anyone who smokes, drinks substantial amounts of alcohol or who participates in 'hazardous sports' (etc. etc.) is concerned about the faceplate screws of plastic accessories, I think I'll just laugh
Kind Regards, John
The discussion so far?
Sorry I’m a bit confused with varying opinions online and from electrician who has seen some of them
In short..
Sockets (3 pin) must have an Earth/CPC/green-yellow to the "faceplate" because one of the 3 terminals is an earth and absolutely must be connected.
Metal Back-boxes should also be earthed.
If it's a plastic switch then the earth goes to the back-box.
If it's a metal switch then earth goes to either the faceplate or the back-box with a link between.
If it's a socket then a link from the earth terminal to the back-box.
Sockets (3 pin) must have an Earth/CPC/green-yellow to the "faceplate" because one of the 3 terminals is an earth and absolutely must be connected.
Metal Back-boxes should also be earthed.
If it's a plastic switch then the earth goes to the back-box.
If it's a metal switch then earth goes to either the faceplate or the back-box with a link between.
If it's a socket then a link from the earth terminal to the back-box.
Thanks very much. Local electrician tells me metal box doesn’t need earthing if the plate is plastic.
He's applying what many might call 'common sense' - but, as you will have seen here, some people will argue that, even if the plate is plastic, the faceplate screws will usually be metal, and therefore theoretically present a risk of electric shock, but only in the event of a (I would say incredibly improbable) combination of circumstances.
Kind Regards, John
He would be quite wrong.
It's very simple...
If there are exposed metal parts they should be earthed. If you have metal backboxes and no earth available then use nylon screws.
It doesn't remove the risk of electric shock if the front plate is removed... but then doesn't remove accessories with the power on
not using the back box lug and using wago's or choc block is a a poor sign of workmanship
Indeed - and a fundamental lack of understanding.
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