Changing the wall socket to the USB one

[jonnythedent]

Morning all
A total diy novice here.
Trying to change my usual socket to the 2 gang usb one. Thought it wont be too difficult swap, then upon opening the old socket, i found 2 earth cables only wired on the metal back box. Will i need to take one and wire it to the new socket plate?
Any help and advice would be greatly appreciated.
Thank you

 

[sparkwright]

You need to take BOTH earth wires to the earth terminal on the socket.

You can run a new wire from the socket to the back box, but this is not compulsory.

Are all your sockets wired like that?

It is not correct to run the earths only to the back box, because once the faceplate is unscrewed from the wall, the socket remains unearthed.

 

[jonnythedent]

You need to take BOTH earth wires to the earth terminal on the socket.

You can run a new wire from the socket to the back box, but this is not compulsory.

Are all your sockets wired like that?

It is not correct to run the earths only to the back box, because once the faceplate is unscrewed from the wall, the socket remains unearthed.

Thank you for your advice.
no it seems that its only this one. Just changed in one of the bedrooms and that one had earth wired into the socket plate although it had a plastic box not the metal one. I will remove both from the metal box and wire into the new socket. Thanks!!