Changing a plug socket - no functional earth

[MissisBoote]

I want to change a plug socket to one that's got the USB sockets.

Nice easy job one thinks but when I unplug the old socket there is no functional earth.

What do I do?

Its a plastic mounting box.

Picture of wires attached and picture of instructions for new socket.

Wiring is pre 2004.

Any ideas? Can I just connect to the earth to the top connection?

Instructions

you use the two copper cores in the green and yellow sleeving.

this sleeving is slid onto the wires when the socket was first installed, it is not inside the cable sheath.

In an ordinary UK circuit you have a protective earth conductor, which is what's inside the sleeving. Possibly your USB charger will use it for some additional purpose.

p.s.

the instruction picture refers to all earth wires being terminated in the back box, but as you have a plastic backbox this is not appropriate. Unless in certain rare cases the terminals in the socket are not big enough to hold all the earth wires, and you have to terminate them elsewhere and run a flylead to the socket. You are I think better off not trying to do that, and I see nothing in your case to suggest it is necessary.

It's possible that the diagram was drawn by someone in a foreign country unfamiliar with UK practice.

pps

yes I think it probably was, because the diagram does not cater for the UK's ubiquitous Ring Final Circuit.

Thank you pigletjohn

So, if I've understood correctly I need to use the two copper wires that are in the single earthed cable and split between the two points marked E on the diagram (one on the top of the new socket and one on the back)

Does it matter that there'll be exposed cable? Or should I cover with electrical tape?

I bought the socket from Wickes

And the other copper earth goes to where my thumb is.

you can put the two copper wires into one terminal.

It would be normal, on a socket with two earth terminals, for them to be connected together with a metal bar. If you can't see that this is the case, and don't have a meter or continuity tester to verify it, you could put a short piece of G&Y from the original terminal to the Functional Earth terminal.

In UK wiring, it is essential that both the earthwires are firmly connected together, and this is best achieved by putting them both in the same terminal.

If you don't have a spare piece of G&Y, you can probably get a bit in a local hardware shop, sold by the metre. I'd get 6mm because it is thick enough not to be easily damaged, but 2.5mm would do.
www.tlc-direct.co.uk/Products/CA6SGY.html

p.s.

and if you expect to be doing any more electric work, buy a hank of G&Y sheathing. You must sleeve bare earth wires. Sticky tape is not not not not not suitable.

www.tlc-direct.co.uk/Products/CAGS3slash10.html

www.wilko.com/electrical-accessories/wilko-earth-sleeving-green-and-yellow-1m/invt/5376648

now I look again, I see the two earth terminals on the socket are connected by a metal bar, so put both wires into one terminal.

This is why I bloody love mumsnet :o

I'll put the earth in the top earthed indicated terminal. This was my initial thought before posting.

Then no need for sheathing.

Thank you