Wiring inline fan/timer

7 Mar 2021
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United Kingdom
Heres my wiring for my inline fan with timer - it's on a fused spur with a 3 pole isolator - I use a 3 core from fan to isolator and a 2 core from isolator to fuse. How do I deal with the Switched live between the isolator to the switch terminal? can I get a single core electric cable? - my other solution is to have the fuse before the junction box making the fan and light a fused circut - would that be ok?
fan wiring.jpg


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To connect as in the diagram, use 3 core between the junction box, fuse and isolator, just connect the 3rd core with a spare terminal in the back of the box, not connected to the fuse at all.
That does leave a switched line to the fan even if the fuse fails, which is not ideal.

my other solution is to have the fuse before the junction box
That is a better solution as it means the whole lot is fused, with the minor disadvantage that the lights won't work if the fuse fails.
I know instructions say 3 amp fuse, however although in the days when lights were supplied with a 5 amp fuse, that may have resulted in the 3 amp fuse rupturing before the 5 amp fuse, with MCB/RCBO protection it is unlikely a 3 amp fuse will rupture before a 6 amp MCB/RCBO trips, so when supplied from the lights it becomes rather pointless.

In the main the wiring in a fan is thinner than even a 1 amp fuse, so if fan stalled likely the fan will burn out before a fuse blows. So seems rather pointless including a fuse when supplied from lights.

If supplied from the ring final yes, a good idea to include a fuse, but then better if included in same device 1674740768523.png clearly marked for fan so everyone knows what the fuse is for.

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