Stupid 1gang 2way switch question

[Dapper]

I know how idiotic this must sound to everyone here, but I just got a new cover plate for a broken light switch and while the existing one is 1gang, 1 way the new one has a L1 L2 and com connectors.
Dumb as it sounds, if i've got a live wire and a neutral wire comin out of the wall (and the earth secured to the mounting plate), which 2 of the three connections do i use?
1st flat and totally clueless about this stuff as you can probably tell!
Also, we've got something on the lighting circuit that keeps blowing the fuse-wire (old style box) whenever we replace it - is there an easy way to isolate whats causing that or is that a 'call an electrician' situation.

 

[Adam_151]

Its live and switched live, not live and neutral

put red (live)in com, and black(switched live) in L1, it doesn't really matter which way round they go (i.e. you could swap them over without problems), its just normal to have it that way

 

[Dapper]

thanks mate - I'll get that done as soon as I can find out what's shorting out my lighting!!!

 

[ban-all-sheds]

1st flat and totally clueless about this stuff

I'd say it's call an electrician time....