Assistance with 3 gang switch wiring

[supermacintyre]

I am preparing to put christmas tree lights up in the garden. I am using a RCD socket in the garage and armoured cable with earth live and neutral running through it and want to fit an external switch to the wall at the rear of the house.
How would I wire this Switch? The switch has 3 connections labelled 1 2 and 3?

 

[hairyben]

I am preparing to put christmas tree lights up in the garden. I am using a RCD socket in the garage and armoured cable with earth live and neutral running through it and want to fit an external switch to the wall at the rear of the house.
How would I wire this Switch? The switch has 3 connections labelled 1 2 and 3?

can't say for sure without knowing what you have there, but I suspect 1 is the common so you should have 1 way switching between 1 and 2.

I'm not sure from your description what you're actually doing; if you're switching a 13 amp socket outlet using a bog standard light switch you'd need to fuse the upstream supply down to 5 amps. A better way to do it would be to use a 13 amp switch-fuse spur.