Extractor fan!!!

Mwoods4757 · Nov 20, 2012

Hi just a quick question about extractor fan wiring. I need to come of a Pir to a fcu then to the fan. Do I need a sw or just take l n e to the fcu then to the fan and link out sw and l at the fan. As there is no where for a sw ina fcu?

Plonker 3 · Nov 20, 2012

Why not just use a fan isolator?

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Octopus · Nov 20, 2012

Think hes fusing down!

Plonker 3 · Nov 20, 2012

Well fit a spur before PIR.

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ayjay · Nov 20, 2012

l-n-e out of the fcu to the pir then a twe from the pir to the fan
set the time at the pir
use a non timed fan

nickblake · Nov 20, 2012

What you want is one of these

Plonker 3 · Nov 20, 2012

nickblake said:
View attachment 15804What you want is one of these

How does that fuse both lives though?

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sythai · Nov 20, 2012

nickblake said:
View attachment 15804What you want is one of these

Click by any chance.....?

Mwoods4757 · Nov 20, 2012

Everything had already been wired so there was a circuit for the fan and a lighing circuit. How ever they now want the fan to come on with the lights and not on it's own. So need to include the lighting circuit with the spur.

nickblake · Nov 21, 2012

Dillb said:
How does that fuse both lives though?

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you dont have to fuse both most fans state that you have to fuse just the permernant live the reason for this is the electronics on the circuit , with out the permernant feed the transistors do not switch so the switch feed does not pass to the rest of the circuit when applied to the input its basically like having a switch after the switch feed so if the fan fails and blows the fuse the switch feed is then disconnected hence the reason the fuse is not needed , its the fan seizing and catching fire what is the reason the fans have to have a lower rated fuse

yes sythi it is scholmore click

vjsmarwick · Nov 21, 2012

If its yo come in with the lights where does the pir come in to the equation ? And if light circuit is fused at 6 A you don't need to fuse down at all go simply fit a fan isolator which isolates all three wires

jumpin jax · Nov 21, 2012

You will need to fuse the fan down to 3A to meet manufacturers instructions, the pir is the switch for the fan not the lights

MDJ · Nov 21, 2012

I haven't seen many fans fused to 3 amps myself even if it is the right thing to do, the vast majority are wired straight off the bathroom light to a triple pole fan isolator and then back to the fan and work off the bathroom light when energised, unless there is a large window in the room working off the light rather than a PIR would be more realistic for the consumer, if you can add a 3 amp fuse somewhere then go for it, if not I wouldn't worry too much about it myself, but the manufactures may not honour the guarantee if it packs up.

vjsmarwick · Nov 22, 2012

Interesting video on YouTube then about wiring a 4" fan by aspect London maintenance company they must be doing it wrong all the time they don't fuse down either !!!

jumpin jax · Nov 22, 2012

It is just an arse covering exercise to follow manufacturers instructions, so the choice is yours whether you do or not but if one was to catch fire and the fuse was not there then who are the insurance company going to come after? Any excuse these days to pass the blame.

nickblake · Nov 22, 2012

jumpin jax said:
It is just an arse covering exercise to follow manufacturers instructions, so the choice is yours whether you do or not but if one was to catch fire and the fuse was not there then who are the insurance company going to come after? Any excuse these days to pass the blame.

hotel fire in london cause by a fan that the motor seized electrician was charged due to failing the manufacturers instructions and not installing a fuse do you want to take the risk if im not mistaken the fine was in the region of £68,000 plus the damage to his reputation