Switch plate earthing advice

[jcs8215248]

I had reason to unscrew a metal 4-gang switch-plate to investigate a noise. I discovered that the earth terminal on the switch does not have a wire to the metal back box, or anywhere else. The lighting cable earths are terminated in the earthing point in the back box.

The wiring to this switch has recently been modified (March 2017) by a qualified electrician in order to change three of the four gangs to two-way switching. He has issued a certificate covering this work.

Should I make a complaint to him or just fix it myself (it took over 6 months to get the certificate so I would rather not have him back!). I have a degree in Electrical Engineering so have a good understanding of electrical wiring and safety, but not the current wiring regulations.

The whole switch actually needs replacing as the noise is caused by arcing on the one circuit that was not converted to two-way. As a temporary expedient I have just used the other pole on this switch.

I have looked at two the other metal switches that were installed in 2011 before I bought the property (and I have the certificates for that work as well). None of the other metal switches have earths either.

 

[westward10]

It definitely needs a cpc to the front plate earth terminal.

 

[Pete999]

Can I suggest you get a competent Electrician into your property to carry out an EICR which is an Electrical Installation Condition Report, as you do seem to be concerned over the state of your properties Electrical installation, it does look from the pictures you have provided, that workmanship may be of some concern here, but of course without first hand knowledge it's difficult to form a comprehensive appreciation, an EICR from a decent contractor will confirm any doubts you may have, there will be of course doubters, but that's my advice, take it or leave it it's yours and your family's safety at stake, good luck anyway.

 

[Deleted member 9648]

There should be a cpc to the switch plate, but once installed to the box the plate will be earthed via the screws to the back box lugs. Once installed there is no danger and the switch plate is adequately earthed. There appears to ne no colour ID sleeving to the black and grey conductors either, all of which suggest a rather slapdash approach rather than a dangerous installation.

 

[westward10]

The fella who did that may call themselves qualified but I doubt they are competent. No cpc to the front plate, no conductor identification and poor terminations. The argument that it is earthed when screwed to the back box is not relevant, it requires a separate cpc.

 

[Pete999]

There should be a cpc to the switch plate, but once installed to the box the plate will be earthed via the screws to the back box lugs. Once installed there is no danger and the switch plate is adequately earthed. There appears to ne no colour ID sleeving to the black and grey conductors either, all of which suggest a rather slapdash approach rather than a dangerous installation.

That's why I suggested an EICR, if this is a sample of the work done at a switch, one can only hazard a guess at what the rest of the workmanship is like, whilst not wanting to scare the OP it will be worth checking, or don't you agree? For peace of mind I guess it will be the OP's choice, but it you had the Gas man around to do a job and were shown pictures of bad workmanship, would you accept it? I wouldn't, there may be be just a few earthing leads to be installed, but we aren't clairvoyant, so we can't tell.

 

[westward10]

Depends on the installation age as these switches are part of recent alterations the rest could be fine.

 

[Pete999]

Depends on the installation age as these switches are part of recent alterations the rest could be fine.

Could be??????

 

[jcs8215248]

Thanks for the comments. The kitchen where these switches are was totally rewired in 2011 when the house was extended. I bought the house in 2016 and had certificates which appeared to show all was OK.

I keep finding other items which do need attention. One obvious one when I first moved in was bare wires poking out of the bathroom wall about18 inches above the tap where a cupboard had been removed (they had put a chocolate bock terminal block on them and taped it up!). I dealt with that one straight away.

Since then we have had some further changes and a utility room created which was almost totally rewired. We had two way switching installed in the kitchen early this year (which provoked this post when I discovered the lack of cpc) and I would have expected the electrician to have attended to or at least drawn it to my attention.

I think I will have to take your advice and get an EICR for peace of mind as there are still some wiring details I still don't understand and there is some more wiring to do in the kitchen. I will see if an EICR could be done at the same time (unless there are any forum members near Great Missenden).

Thanks for the feedback.

 

[Deleted member 9648]

The fella who did that may call themselves qualified but I doubt they are competent. No cpc to the front plate, no conductor identification and poor terminations. The argument that it is earthed when screwed to the back box is not relevant, it requires a separate cpc.

I wasn't arguing about anything, simply stating a fact that when installed the faceplate will be adequately earthed.

 

[westward10]

I wasn't arguing about anything, simply stating a fact that when installed the faceplate will be adequately earthed.

To adequately earth it a separate cpc is required.

 

[Deleted member 9648]

In theory yes, in practice it will be adequately earthed to enable ADS when screwed back, if that was not the case then all metal covers on distribution boards would have a copper earth link, as it stands some do,most don't.

 

[Midwest]

In theory yes, in practice it will be adequately earthed to enable ADS when screwed back, if that was not the case then all metal covers on distribution boards would have a copper earth link, as it stands some do,most don't.

Fair point, but I guess the difference is the metal lid of a CU, doesn't have wires connected into some switching mechanism on or in it?

 

[Bobster]

So long as the fixing lugs on the back box aren't the adjustable type there is no regulatory requirement to fit an earth link to the switch plate. Good practice sure, but there isn't a reg.

 

[Midwest]

Another fair point. Do the regs actually stipulate that if a metal back box has one fixed lug, then earthing tail is unnecessary?

 

[Jay Sparks]

Another fair point. Do the regs actually stipulate that if a metal back box has one fixed lug, then earthing tail is unnecessary?

It mentions it in GN8 and gives some pretty picture of the different back boxes with fixed lugs and without but I'm not sure on an actual regulation number and my copy is in the van.

Jay

 

[Bobster]

There is no regulation number. Just general guidance. s.

 

[westward10]

Another fair point. Do the regs actually stipulate that if a metal back box has one fixed lug, then earthing tail is unnecessary?

As above GN8 makes reference and quotes Reg 543.2.7 where a separate cpc is required if containment or cable sheath is used as the cpc. It also refers to fixed/unfixed back box lugs but does not provide a supporting Regulation. To me a similar principle applies with metal switch plates whereby the fixing screws should not be relied upon to earth the accessory as per Reg 543.2.7 where they suggest the same, a separate cpc is required.

 

[kingeri]

If the cpc went to the switch plate I could forgive a lack of flying lead to the back box. But not the other way around. Surely??

 

[westward10]

Reg 543.2.7 suggests the front plate screws should not be relied upon to earth the accessory.