single core cable for earthing

[curium]

hi I've just had some plastering done so had to take the sockets off.

All the back boxes are metal and I noticed that only the one that was recently installed for the boiler has an earth cable from the back-box to the ring-circuit earth.

I wanted to get some copper cable to earth the other back-boxes since now I've noticed that they have none. I have the earth cable sleeving from homebase but can't find the cable.

Is it possible to buy it or should I just buy some twin+earth and strip the copper from that?

Incidentally, for the cooker switch (45A) should I buy special thickness cable for earthing the back-box since I notice that the supply cables look quite beefy or can I just cut 2 lengths of copper from the T+E and twist them around each other?

Cheers!

(I don't think i need to get an electrician in for such a simple job, do I? Especially since the spark who put the boxes in originally didn't bother!)

 

[chivers67]

If one of the lugs is fixed on the back boxes and not lose (like the other one probably is) then this is normally adequate as when the boxed is screwed in it makes a connection to the earth on the socket.

If however they are both loose then it's better to have the earth connected normal T&E striped and sleeved should be ok. See what size the cpc on the cooker cable is to give you an indication of how much is required.

 

[curium]

See what size the cpc on the cooker cable is to give you an indication of how much is required.

The cooker cable was multiple cores twisted around each other. It was much thicker then the cable to the sockets on the ring. How would I gauge its size, just with a ruler to see the diameter of each of the cores that are twisted?

 

[holmslaw]

..

 

[sparkwright]

Though you could use single core earth wire, it may be stranded and the earths in the wiring are more than likely solid. Doesn't really matter, though wires do tend to hold in better if they are the same.

You will have more joy in buying t+e by the metre than you will single core earth - as you don't need a lot. Somewhere like Wilko probably still sells 2.5 mm2 t+e by the metre.