I found this while doing some jobs

[plugwash]

A few reasons

1: While it's acceptable to use the screws to earth the back box AIUI it's not acceptable to use them to earth the socket and stuff plugged into it. So if you have a system which relies on the conduit for earth then you will need a flylead.
2: Plastic lightswitches don't generally have earth terminals or earthed screwholes. Some other accessories may be similar.
3: Just because BS7671 doesn't require earth flyleads doesn't mean they are not a good idea. Especially if installing in adverse conditions.

 

[WabbitPoo]

This is why I rate this forum so highly - never fail to learn something (nearly) every day

 

[WabbitPoo]

I have seen quite a few corroded faceplate screws over the years due to damp walls etc. Is there not a danger of the effectiveness of them as earthing points to be compromised?

 

[333rocky333]

Interesting stuff, thanks. Why have earthing points in back boxes with at least one fixed lug then?

Not to forget
armoured cable and pyro which use the sheath for the supply earth

Also metal boxes are sometimes used as junction boxes with plastic blank fronts as well as a multitude of uses aside from sockets.

I would suspect Bs standards force them to fit earth lugs due purely to the fact there metal,
up till about 1970 i think, you brought the earth terminals seperate and fitted them yourself.
Even plastic boxes have a facility for fitting an earth terminal nowadays

 

[ericmark]

For my mother today I fitted two switches to supply an up lighter and I put the earth into the earth terminal in both switches. But really there was no need switches and up-lighter both class II.

This OTT approach is common but also the comment not required depends on if all other things comply.

The 1mm wire used for testing has a defined pressure behind the wire and when I use any form of stopper to block holes I don't then test to see if a 1mm wire with that force would go through the stopper. In the main the stopper has not dried so it would be impossible. Neither do I try to see if I can remove the stopper without a tool.

Some common sense is required. It would appear from the picture a back box intended to be used within a wall has been used to surface mount a socket? It is likely the 1mm probe could penetrate the box from above so it would not comply. As to if a 12.5mm item could enter from any other direction also seems likely. Yet I am sure at some time I have used a inappropriate back box and what one has to consider is.

Is it an immediate danger.
Is it a potential danger.

Even if it does not follow regulations it may not fall into either of the above.

Although what you show to my mind does not comply. I would alert the owner that there is some poor workmanship but that would be the limit. If the owner then asked for a report then I would give them one. But if the owner did not care I would not take it any further.

I am not saying this is the right way but it is what I would do.

 

[333rocky333]

It would appear from the picture a back box intended to be used within a wall has been used to surface mount a socket?

It was screwed to a joist in the stud wall.

Though question is, by you relocating it have you now put the cables out of zone, if so on reaction to his work being scrutinised he could come back on you

 

[Risteard]

I have no idea how proprietary metal conduit permits fixing a wire to it's end though...

You don't. The conduit itself is the cpc.

Although it's pretty common practice nowadays to run (a) separate green/yellow single(s) with the phase(s) & neutral.

 

[deadshort]

If the customer is unhappy with the workmanship they must give the guy the opportunity to comment and if requited put it right. As has been said, if you have altered or moved and unscrewed the back box from it's fixing point you have given him his out.

Regards,

DS

 

[deadshort]

Oh and I forgot to mention the lighting cable, that used to go to a wall light, left sticking out of the wall, with a choc block on the end and no clue as to if it was live or not (it wasn't). Not even any black tape around it.

If the cable is redundant and dead why would the electrician put "black tape" round it ?

DS

 

[WabbitPoo]

Beacuse by not doing so he left the customer feeling quite scared as to its safety. Customer is an old 'un so not much of a complainer. She didnt know if it was live or dead, safe or not. Why not pull the cable back through? Looking at the situation, it is easy to do so as it runs up to a false ceiling above, to which one has easy access within.

Anyway, thanks to all for their input.