I am wiring an humidstat extractor fan for my bathroom. The instruction say that 'wiring should be via a 2 pole isolator with separation of a t least 3mm'. Sorry for being ignorant, but I simply want to connect this device to disused ligting circuit . I can connect the live and neutral terminals and the fan works fine when I switch the light switch on and the humidity control picks up moisture. Now I want to wire the fan so it is permanenty connected, can I simply replace the light switch with a 3amp fuse box?