Earthing light switch to mains earth

[pmx_super]

I've got a metal clad light switch in my garage, but no earth on the lighting circuit.

Would wiring the earth from the light switch into the earth terminal in a juntion box that's on a spur from the ring main provide an effective earth, or would doing so introduce a new risk that's more dangerous than the un-earthed switch?

 

[riveralt]

I assume that none of your lighting circuits have an earth - in which case none of your lighting circuits should have any metallic switches or lights that are not class 2 (double insulated).

So the first thing is to replace the metallic switch in the garage with a plastic one and any other light fittings.
The second thing would be to consider having your lighting circuits upgraded to the incorporate a proper cpc that goes back to the main board on its own circuit. In other words don't borrow an earth from the ring final circuit.

Alternatively look at this site:
http://www.double-insulated-lighting.co.uk/

 

[pmx_super]

Hmm, guess I should buy a plastic switch and surface mount box then.

I'm ashamed to admit I bought the metal switch the other day because I like the look of it in the garage. Only afterwards did it occur to me that I've go no earth on my light circuit