I'm adding an extra light switch on a long corridor (so that the lights can be turned off and on at both ends).
The cable specified is 3 core and earth - BUT there's no earth on the switch I have and I'm using a dry lining box again with no earth connection (this is the same at the other end of the corridor), so I'm presuming that it doesn't need to be earthed? Also if the switch doesn't need to be earthed can I use twin and earth - 1.5mm and use the redundant earth for say the common, although the earth has no protective sheath?
I ask because I currently have no 3 core and earth but will buy a box if needed - although I only need 5 meters!
Great site - use it A LOT