Best practice earthing metal plates and/or back boxes - fly lead or not?

[ninemaverickbars]

Hello everyone,

Following on from my previous post where I received advice on taking a spur off a 40a feed (thank you). I performed the work today, installing a surface fixed metal faceplate and back box. When terminating to create the spur (tight fit into terminals with both 6mm and 2.5mm!), I noted that the previously installed 2 gang metal plate and back box did not have an earth fly lead.

Because I don't really know any better, I tend to use an earthing fly lead where the faceplate and back box are both metal, or just the back box is. I understand that there is often a common earthing rail within a socket, allowing for it to be earthed via the screws into the back box. Perhaps the fly lead is therefore redundant?

The socket I installed was a 1 gang MK unit complete with back box, metal as I say and it had a separate earth terminal for connection of a fly lead. The 2 gang socket however, did not have a separate earthing terminal.

My question is, when it comes to metal faceplates and back boxes together, or metal back boxes with a plastic plate, is it always best practice to use a fly lead, or generally better not to unless the socket has a dedicated terminal for it?

I hope that makes sense as a question and isn't opening a can of worms.

Many thanks

 

[James]

You have opened a can of worms.

in my opinion, the back box, the socket earth terminal, screws and face plate need to have a reliable connection to earth.
how that is achieved is down to both personal preference and the specifics of the socket type and back box.

most of the time a fly lead is not required but in some circumstances it might be.

hope that clears things up, clear as mud to me!!

 

[ninemaverickbars]

You have opened a can of worms.

in my opinion, the back box, the socket earth terminal, screws and face plate need to have a reliable connection to earth.
how that is achieved is down to both personal preference and the specifics of the socket type and back box.

most of the time a fly lead is not required but in some circumstances it might be.

hope that clears things up, clear as mud to me!!

Ugh, oh dear.

Well, I reasoned that you can't really create an issue by using one, providing it's terminated correctly, so I'll keep doing it I guess.

In my case, the face plate and back box came together in the same packaging. Both are MK and MK saw fit to put both the fly lead connector on the back box and a separate terminal on the face plate. I thought they must have done it for a reason, so I went with the path of least resistance.....de dum tsshhhh. Thats my first ever electrical joke, does it show?

Thanks James.

 

[brianmoooore]

A flylead between a metal back box and a metal face plate is always going to be 'best practice', even if not always required by the regs.

 

[ninemaverickbars]

A flylead between a metal back box and a metal face plate is always going to be 'best practice', even if not always required by the regs.

Thanks Brian. I'll keep doing it then, no harm I suppose. I am lucky in that being DIY, I have the luxury of time when it comes to this kind of thing.