as a technical answer it will be 6mm twin and earth, but an advisory answer would be to get a qualified electrician to connect it and check the earthing abilities of the earth wire with an earth loop impedence tester. The earth wire is your protection against electric shock in the event if a fault, simply connecting the green/yellow earth to the green /yellow wire in the socket does not prove the earth path is sound. Cheers
Kenjo, July 2012
