replacement fan isolator switch

[bill32uk]

have recently purchased a new fan isolator switch for bathroom fan "click mode". The problem i have is it doesn't state on the back a supply side or load side Terminals are L1, L2,N there are 2 of each but some are marked "common" am i right in thinking the ones marked common are supply side please can someone shed some light on this for me as i do not want to change switches unless 100% percent sure. Original one is cracked

Thanks

 

[BigJon]

Common should be your supply.
I tend to put supply to the top and outgoing cables to fan on bottom when it comes to fan isolators that dont state otherwise ( not that it matters too much,its just a 3 pole switch).
Remermber to mark what went where before you dismantle your switch just incase.....