Settle this Argument.

[telectrix]

metal faceplate 1363 socket. obviously needs to be earthed. argument is whether the back box should be earthed just because it's a metal faceplate. ( i know it's considered good practice to fit a fly lead anyway, but that's not the argument. the argument is with the faceplate being metal, does that make any difference. my argument is No, other party says Yes. Who is right, going by BS7671?)

 

[telectrix]

Not forgetting DIY decorating when the faceplate is pulled away from the wall for papering or painting.

true, but we'renot talking about what may or may not be desirable. we're talking about what the regs. stipulate. was around 2003 i think, in an amendment to 16th. where the stipulation for not earthing a back box was changed from 2 fixed lugs to single fixed lug.

 

[Risteard]

I mentioned this way way back during conversation with an inspector. He said though this is true they cannot be relied on for bonding purposes therefore the back boxes should have additional bonding.

But you're not bonding it - it's not an extraneous conductive part. You are earthing an exposed conductive part. Although a separate conductor is not required with one or more fixed lugs I personally would always do it.

 

[The Ghost]

543.2.7 Where the protective conductor is formed by metal conduit, trunking or ducting or the metal sheath and/or armour of a cable, the earthing terminal of each accessory shall be connected by a separate protective conductor to an earthing terminal incorporated in the associated box or other enclosure.

 

[Ian1981]

That regulation ,is if say you used metal conduit as the cpc.
A tail Earth from the back box is needed connecting to the socket faceplate or to whatever the accessory serves as.

 

[The Ghost]

Would you have a metal surface box on anything else? i.e. galv etc.

 

[Ian1981]

Possibly yes but if you used singles within the conduit with a cpc as a separate conductor and not the containment, that regulation isn't applicable.
With a separate cpc you are mearly earthing the conduit through the fixing screws inserted into the back box fixing lugs.

 

[The Ghost]

For flush metal back boxes with two fixed accessory-fixing lugs, as shown in Figure 9.6, the box can be considered adequately earthed through the earthing straps and eyelets of the accessory and the fixing lugs on the box. An earthing tail is not therefore essential although for best practice it is highly desirable. GN8

 

[Ian1981]

Agree but not sure why you quoted that specific regulation earlier?

Wires crossed (pun intended)

 

[The Ghost]

It's the only reference in the regs I can find on the subject thought I would just put it there. I am assuming metal clad socket is surface with surface box, and would be with galv. Of course the OP may be referring to any metal back box that is not entirely clear but I think it highlights that there are specific items that do and some situations that don't require an earth hence no definitive answer.

 

[suffolkspark]

with regards to doubling over I'm afraid I'm one of those that doesn't always......
It depends on the accessories, hager, mk and crabtree have square terminals so you have to, but some brands have round terminals, click, eaton, and the cable, even 1mm centers itself nicely under the centre of the screw and I never have any problems, definitely depends on the accessory brand.
agree with most people that have said if theres 1 fixed 3.5mm screw lug it doesn't need a fly lead to the back box, that is 100%.

 

[ashg285]

I don't fit fly lead unless surface metal boxes.

 

[ashg285]

And as for doubling over I always do this on 1mm or 1.5mm cable

 

[littlespark]

Regulations are built on worst-case-scenarios... I would earth faceplate AND backbox, surface or not.
Imagine a case where the live AND the earth wires are not tight in their connections and drop out. Live touches back box, creating a danger.
The only protection now is the earth wire to the back box.

Doubling over conductors - Any screw termination must be secure. A single core cannot be deemed secure.
I still cannot believe there are older sparks out there still twisting solid conductors together.

 

[ipf]

Regulations are built on worst-case-scenarios... I would earth faceplate AND backbox, surface or not.
Imagine a case where the live AND the earth wires are not tight in their connections and drop out. Live touches back box, creating a danger.
The only protection now is the earth wire to the back box.

Doubling over conductors - Any screw termination must be secure. A single core cannot be deemed secure.
I still cannot believe there are older sparks out there still twisting solid conductors together.

Where'd you get that one from?

As regards 'older sparks', that certainly doesn't apply to those with a bit about them. I'm damn sure there's a lot more common sense used, in general, than the younger end.

 

[sparksburnout]

"Live touches back box, creating a danger."
How??? Kindly explain.