For some reason, not that I am complaining, I have had a number of jobs recently that involve the fitting of timer extractor fans linked to the lights in bathrooms.
I have noticed that manufacturers instructions are stating that the fan must be able to be isolated for maintenance - no problem with a 3 pole isolator but also the circuit must be protected by an FCU with 3amp fuse. And where they don't mention the FCU, like Vent Axia, they imply the same by stating that the circuit must be protected by a 3amp fuse.
Fitting a switched FCU as a direct replacement for the lighting switch would be ideal, but as we know without a neutral at the switch this becomes a problem, especially when chasing new cable to the switch is prohibited.
Without this option the only way I can think of designing such a circuit is by interupting the lighting circuit with a jb taking the line/neutral and cpc which feeds through a FCU onto another jb from which the cable to the switch - switch live to the lights and three core through a three pole isolator to the extractor are linked.
Am I over thinking this one or Is there another way?
I have noticed that manufacturers instructions are stating that the fan must be able to be isolated for maintenance - no problem with a 3 pole isolator but also the circuit must be protected by an FCU with 3amp fuse. And where they don't mention the FCU, like Vent Axia, they imply the same by stating that the circuit must be protected by a 3amp fuse.
Fitting a switched FCU as a direct replacement for the lighting switch would be ideal, but as we know without a neutral at the switch this becomes a problem, especially when chasing new cable to the switch is prohibited.
Without this option the only way I can think of designing such a circuit is by interupting the lighting circuit with a jb taking the line/neutral and cpc which feeds through a FCU onto another jb from which the cable to the switch - switch live to the lights and three core through a three pole isolator to the extractor are linked.
Am I over thinking this one or Is there another way?