Installing inline extractor fan

4 Aug 2006
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United Kingdom
Ive bought a greenwood airvac TF115TSK (timed) to install in the bathroom, ive read the wiring instructions and iam fairly sure on how it has to be wired but iam not positive so please feel free to correct me.
The diagram is here (the one on the left) it say about using a double pole isolating switch, do i have to use one and if so wouldnt it be better to use a pullcord 3 pole isolating switch?.
From what i understand of the diagram + if using a 3 pole isolator i have to connect blue N and Red L2 wires to the ceiling rose then to the isolator in the same order, then the red from the light switch goes to L1 of the isolator.
Then all i have to do is connect the fan to the isolator in the following way
N - N
L - L1
SL- L2

Thanks in advance for any help. ;)
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The manufacturer is recommending a fused DP isolator, although the wiring diagram you link to doesn't even specify a fuse rating, which makes the whole thing seem a little pointless.

My interpretation would be that they are recommending the fan be on a circuit fused down to 3A, therefore a triple pole isolator doesn't meet the manufacturers requirements. This is because you would be relying on the 6A/10A fuse for the lighting circuit in the main CU to also protect the fan.

If you follow the wiring diagram linked to in you will need to re-route the supply loop in/out connections at the ceiling rose into an FCU to supply the fan and light. If you can manage that while keeping the FCU in a suitably zoned, accessible location then following the wiring scheme on the Airvac site shouldn't be a problem.

Alternatively, you could fit a DP light switch in the bathroom, with one pole operating the lights and the other fed from the ceiling rose via an FCU, and then onto the fan.

Also, not that I recommend it, but you could say sod the FCU and feed the extractor straight through a TP isolator. It's unlikely to burn your house down as a 6A type B breaker (assuming your CU is fitted with breakers) is likely to go far sooner than a 3A BS1362 fuse.
To be honest iam looking for the easiest option, i dont mind doing electrical work but iam no electrician :oops:
The last thing i want to do is to have to chop out the wall to put any switches in because ive just took out a dimmer switch that the last owners put in and the rooms have been decorated :(
Thanks again for your help
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Are you not able to put a 3amp FCU before the pull cord switch? As it is an inline fan situated (I assume) in the loft, and the cable from the pull cord switch (again, I assume) will run in the loft, surely it's simple enough to put a 3amp FCU before the pull cord, the FCU will be situated close to the fan so if work needs to be done on it it should be obvious what the FCU is there for, and the FCU will actually isolate the pull cord also as a bonus.
Because of the wiring arrangement that you may have, the above might not be viable, but it's a thought.
I meant which was the easiest out of the options you gave.

That really depends on your existing installation. If the bathroom is on the top floor and the connections to the ceiling rose are easily accessible from the loft, you could move the supply loop in/out cables into the supply side of an FCU and mount it in the loft. It would then be a simple job to take a new supply to the rose from the load side of the FCU. As the fan will also (presumably) be located in the loft somewhere near the cables to the ceiling rose, this will provide a local means of isolation.
thats pretty much spot on how the wiring is, all the of it is easy to access through the loft as its just inside the entrance.
So i can put the FCU in the loft? as that would be great as i dont really want to see it.
Would i still need a double pole isolating switch like the manufacturer recommends .

Make sure you get this confirmed by the pro's on here, but yes, your FCU in the loft is fine I think, as that's where the fan is. It's purpose is to isolate the power if the fan needs to be worked on, cleaned, whatever. As yours is an inline fan in the loft, then the FCU nearby, in the loft, is just right. And I don't think you need another double pole isolator no, as the FCU is your double pole isolator.
It's pretty much how I have my toilet and bathroom fans installed.
And like I said in my earlier post, if the FCU should go before the switch, then you have the added bonus that it isolates the switch also, so if it needs changing in the future, or taken off for decorating or whatever, it's easy to isolate that also.
can you just confirm something for me please thats on the diagram, that picture of a circle with a cross in is the light isnt it.

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