Earth inside power socket box

[rossburton]

I'm adding some new power sockets in the garage and being a bit of a newbie I'm a bit confused about correct earthing. The mounting box is plastic as is the face plate, and the mounting box has an earth terminus, presumably for a flying earth from the face plate. Do I need to connect this earth if both the face plate and mounting box are plastic, and if so what is this for?

 

[EFLImpudence]

You must connect the cpc (earth) to the faceplate even though it is plastic.

The terminal in the box is just for 'parking' a cpc when not needed.

 

[rossburton]

Obviously I'll connect the earth to the faceplate, *especially* in the garage where sharp spiky electrical things are common. So the box terminal is basically in case I was replacing the box in an existing installation that had a flying earth and I'd need somewhere to put it?

Thanks,
Ross

 

[Iggifer]

or if you were using it for a purpose other than a socket, ie lightswitch

 

[sparkzzz]

Thats exactly right ross, you would usually use them for light switches as most (unless metal fittings) don't have an earth terminal.

 

[PrenticeBoyofDerry]

As the back box is plastic, you are not required to earth it.
If metal back, then depending on the lug fixing on the box it may need to, it may not.

Just to be awkward:
If it was for a plastic lighting switch plate (with no earth term) and backbox (with earth term), then continuity of CPC/earth would be required, this does not necessarily mean that this must be terminated at the terminal offered at the backbox. But as that provision is available, it would be logical process to so. awkward moment completed

 

[rossburton]

The possibility of using the box for a lighting switch makes everything clear and is obvious in hindsight. Thanks everyone.

 

[securespark]

Also, sometimes these pattresses are used as junction boxes and the terminal can be used for earths in that case too.

 

[ban-all-sheds]

... garage ... The mounting box is plastic as is the face plate

Use metalclad.

 

[Spark123]

As the back box is plastic, you are not required to earth it.
If metal back, then depending on the lug fixing on the box it may need to, it may not...

Likelihood in a garage is that it will be surface mounted so a metal box must be earthed with a fly lead as it is an exposed conductive part. I personally hate seeing normal metal boxes used in garages, metal clad is much nicer.