Earthing back boxes ??

[Dazza1976]

Hi all, just wondering if you bother to earth metal clad back boxes for switches and sockets ???
I understand that some schemes require you to do this and others dont. I have also heard some people saying that if the switch or socket is metal thaen you must ?? Why is that ?

I dont really see the need for it myself , If a live conductor was to come off and touch the back box, the screws could then become live, but they are already earthed via the faceplate anyway, so i really dont see why it needs to be done ??

I will be interested to hear all your views on this .

 

[zedess]

No i dont...havent got time

 

[zedess]

And if i did....i wouldnt....

 

[LlandrilloSpark]

I was taught it was supplementary bonding, all exposed conductive parts of a circuit have to be bonded to earth, the screws alone are not good enough, so i was taught to bring a small cpc tail of the back box and onto the faceplate where the main cpc terminates, after all these metal back boxes are supplied with a terminal for a good reason, i always do it and if im doing remidial work in a dwelling and i see it missing i put it in.
I think also it has something to do with the lugs of the backbox, the place where the patress screws screw in, if you wiggle them you will notice they are loose in order to accomodate awkward screws, hence and even better reason to include the cpc tail

 

[scotsparky]

ok heres what i have been told

It is good practice to put a link in from backbox to front plate. However if the backbox has a solid lug on it it is not a requerment. if the backbox is of the type wher the fixing lugs are movable it is.

 

[Phil]

i always do it, got shown it that way years ago and is has stuck.

 

[Sintra]

Or if using a conduit or cable sheath as a cpc then the back box must be earthed also. Reg 543.2.7 p 131

 

[Hawk81]

i always do it too

 

[ghost]

I always fit a bond, I use a bit of 1.5mm stranded single earth (conduit cable) rather than a solid earth with sleeve. Old habit, taught that way at NEEB. There seems to be different views, but it's what I've always done.

 

[Des 56]

Good practice,yes,but in many cases not a requirement,so be cautious condemning installs where it does not exist

 

[keniff]

yeah one fixed lug there is no need but i always do, never see me without my roll of 1.5 single earth cable lol

 

[Deleted member 9648]

Not a requirement as long as the backbox has at least one fixed lug and the accessory has earthed rings on the fixing holes....(sockets will but lots of switches etc wont)..........I always install a flylead anyway unless the box is really busy when I might omit..(ie when some numpty has put a 25mm box in with 3x 2.5's in)....

 

[Lucas]

Ill always earth the backbox incase a DIYer comes along and unscrews the faceplate too paint or something and then the backbox is always earthed

 

[High Tower]

Is there anything wrong with using the cpc off cuts to create a fly lead I use conduit singles but I know a few that use off cuts from t&e

 

[ezzzekiel]

as there is no need to add flylead, then you can use any spare bit of cpc you have to hand, i tend to fit except for crammed backboxes where i will leave out.