Earthing on a plastic back box with chrome face plate?

[vincechiew]

A couple questions, apologies for poor description/electrical knowledge and spelling, here I go...

In my house where the back boxes are metal they have an earth wire wired directly into them at the point where the face plate screws into it (for lighting and plug sockets).

1. Does this mean I do not need to seperately earth the chrome face plate into the back box? Or should I also wire the chrome face or even just remove the earth from the back box to the face plate?

2. In the extention the back box is plastic (for lighting) and there is only a live and neutral wire. Can I use a metal face place?

and finally,
3. There is a loose wire coming into my bathroom which use to power the electric heater which has now been replaced with a combi boiler. I would like to use the supply for a shaver socket and have a chrome shaver face plate with a plastic back box. Does the face plate need to be seperately earthed or can I bond it via the earth in the power supply?

Any pointers greatly appreciated.

Vince

 

[danlightbulb]

1. Does this mean I do not need to seperately earth the chrome face plate into the back box? Or should I also wire the chrome face or even just remove the earth from the back box to the face plate?

No - you need to earth the face plate and the back box. You can do this via a link with earth sleeving.

2. In the extention the back box is plastic (for lighting) and there is only a live and neutral wire. Can I use a metal face place?

No you can't use a metal face plate. They have to be earthed.

3. There is a loose wire coming into my bathroom which use to power the electric heater which has now been replaced with a combi boiler. I would like to use the supply for a shaver socket and have a chrome shaver face plate with a plastic back box. Does the face plate need to be seperately earthed or can I bond it via the earth in the power supply?

No problem with using the earth that is in the existing cable.

 

[vincechiew]

Thanks!!!

I guess there isn't a simple way of running a earth wire to the socket without ripping out the walls?

 

[luminaire]

Does the face plate need to be seperately earthed or can I bond it via the earth in the power supply?

It also needs to be supplementary bonded.
And note this work should be notifiable.

 

[danlightbulb]

It also needs to be supplementary bonded.
And note this work should be notifiable.

Would be interested to know why the existing earth in the T&E cable is not enough protection?

Surely fitting a new shaver socket face plate in place of an old heater flex outlet is not notifable work?

 

[luminaire]

3. There is a loose wire coming into my bathroom which used to power the electric heater which has now been replaced with a combi boiler. I would like to use the supply for a shaver socket and have a chrome shaver face plate with a plastic back box. Does the face plate need to be seperately earthed or can I bond it via the earth in the power supply?

Isn't that the same as adding a new supply to the bathroom?

If it's another metal fitting in the bathroom, won't it also need to be bonded?

 

[danlightbulb]

Not that i'm an expert, but to me it seems the supply is already there and supplied by twin and earth cable. All that the OP needs to do is fit a backbox and shaver socket face plate in the same location.

And isn't the earth in the twin & earth cable enough earth bonding? Surely earth bonding is for metal objects not otherwise connected to earth i.e baths, pipes, etc.

 

[luminaire]

And isn't the earth in the twin & earth cable enough earth bonding? Surely earth bonding is for metal objects not otherwise connected to earth i.e baths, pipes, etc.

P30 & 31 OSG states: "the protective condutors of all power & lighting points within the zones must be supplementary bonded. The bonding connection may be to the earth terminal of a switch or accessory supplying equipment.
CPC may be used as supplementary bonding conductors."

In other words all the protective circuits within a bathroom have to be connected.

Mind you next year they wont!

 

[danlightbulb]

Fair enough the regs are the regs I suppose no matter how OTT they can be at times.

Whats changing next year out of interest?

 

[luminaire]

Whats changing next year out of interest?

17th Edition = no bonding required.
Every thing's going to be RCD protected

 

[vincechiew]

Thanks guys, this seems a bit of a minefield but are you saying it will still be safe if I don't supplementary bond the metal shaver faceplate but it won't meet regulations until next year?

 

[securespark]

Whats changing next year out of interest?

17th Edition = no bonding required.
Every thing's going to be RCD protected

And a bit more besides: search for the stuff. There have been many posts here. But socket outlets will be allowed in bathrooms, providing you have a large one! 3m from edge of Z1 you will be allowed a socket outlet.

Direct & Indirect Contact are changing their names by deed poll.

IR threshold going up to 1Meg mimimum. And a few others besides.