Earthing back boxes..

[alexg]

What possible reason can there be not too?
Sounds like a "logical" interpretation of a regulation with regrd to unfixed equipment?

 

[baldsparkies]

Come on fellas.

When the accessory is screwed back the earth connection to the box is provided through the fixing screw from the plate.

You will probably find the CSA of the screw is more then the 1.5 fly lead that would be connected.

Nice, Jason, a practical common sense approach to the situation, your a thinking mans electrician.

 

[mikeymoo]

Ive seen rusty and painted plate screws stripped threads etc. I would rather just connect 4 inch of cable and be done with. I think leaving it off is relying to much on the person that removes it at some point to put it back properly.

 

[Spudnik]

Ive seen rusty and painted plate screws. I would rather just connect 4 inch of cable and be done with.

Indeed and there is no reason why not.

However, i bet if you tested that screw with the plate still on, it would still be continuous to earth.

I would be more concerned as to why the screw is rusty!!!!

 

[baldsparkies]

Don't think I will lose sleep on this one, every man to his own.

 

[mikeymoo]

I would be more concerned with someone getting hurt.

 

[stretchyboy]

Jason is perfectly correct, the important use of this knowledge is not so much when you are fitting your own jobs(as that is often personal choice) , but when you are testing someone elses work. It is really imprtant to know the regulations inside out in order to have all the answers to give to anyone who disputes the faults that you are picking up in an installation.

Good post all

 

[stevo09]

just taken a look on the NICEIC website and somebody asked the question ""

"Could you please tell me if it is neccasary to earth a metal back box if it has one fixed lug" The reply from the niceic was "Where an accessory has an earthing terminal incorporated, the protective conductor should be connected at the earthing terminal

Myself i would go with that.

 

[Mr Mark Sparks]

just taken a look on the NICEIC website and somebody asked the question ""

"Could you please tell me if it is neccasary to earth a metal back box if it has one fixed lug" The reply from the niceic was "Where an accessory has an earthing terminal incorporated, the protective conductor should be connected at the earthing terminal

Myself i would go with that.

the truth is there are a few instances where the nic take a safer stance than others
ie they say max ze on tt 100 ohms but the regs say 200

i fly lead but its my choice i agree that with a fixed lug there is no need, when doing r1r2 tests i often test to the screw and its fine (flylead or not)

when doing a p i r if there are no flyleads on fixed lug boxes i dont write it down

 

[stretchyboy]

Ditto Mark Sparks, I usually fly-lead but will not put it on a PIR if someone else hasn't unless there is two adjustable lugs.

I always think that it ought to be done as a sparky may have the socket front off and if the cable is damaged at the entry to the box, then it may touch and liven the box. In that instance if the box wasn't fly leaded it could become live as the earth would be connected to the socket and the socket seperated from the box at the crucial moment.
Having said that, we can only go by the regulations as they stand today and only use our knowledge, guidance and best judgement. We cant fail things for not looking 'nice' .................. unfortunately

 

[mikeymoo]

This is what makes this forum invaluable to me. Great posts and sound advice.. Cheers guys

 

[Spudnik]

.... may have the socket front off and if the cable is damaged at the entry to the box, then it may touch and liven the box. In that instance if the box wasn't fly leaded it could become live as the earth would be connected to the socket and the socket seperated from the box at the crucial moment.

Thats you on the naughty step then as you should not be working live.

Therefore if the socket front was removed and the above happened, then only you would be to blame if the inevitable happened.

Work safe guys

 

[stretchyboy]

Thats you on the naughty step then as you should not be working live.

Therefore if the socket front was removed and the above happened, then only you would be to blame if the inevitable happened.

Work safe guys

Very true, but if you were trying to get a Zs at a light switch ................

 

[Spudnik]

Very true, but if you were trying to get a Zs at a light switch ................

If thats the case then normally the CPC's are connected to the box as there is nowhere else for them to go, with a flylead to the metal accessory if fitted.

Even so, Zs should be taken at the fitting.




i LOVE splitting hairs

 

[stretchyboy]

Ok a "T" earth socket then, where you cant get your standard plug from your meter into it and you haven't got an adaptor