Wiring an inline extractor fan with flex

[matt_180]

Hi,

The house I've moved in to doesn't have an extractor in the main bathroom so I'm looking at placing an inline extractor in the attic directly above it. Problem is...I'm using smart lights that need to be powered on all the time therefore don't want to use the existing pull cord to control it.

I'm thinking that the easiest thing to do (if the regs permit it) is to wire it using 1.0mm flex, put a plug on the end and then use one of those WiFi controllable switches that could plug in to an existing socket in the the airing cupboard next to the bathroom. I can then get the fan to come on automatically with the light, or put a wireless humidity sensor in there etc. This would mean that I wouldn't have a standard fan isolator switch outside the door, but it could obviously be isolated by unplugging it (plus would be fused at 3A via the plug).

Would be interested to hear any thoughts on:

a. would wiring this in flex and bringing it down to an existing socket in the airing cupboard comply with the regs considering it's a permanent installation?
b. is there a better way of doing this? how are extractor fans usually controlled in a situation where you have smart lighting (e.g. phillips hue) and therefore prevent you using a switched live.

Thanks!

(btw - I tried to post this in the DIY forum but couldn't get access - I think the link may be broken to request access via staff? Sorry if I've asked in the wrong place).

 

[littlespark]

There’s no issue running the fan as you describe. In fact, it’s quite a good solution as you can trigger it to come on with a smart signal, then run on with a timer, separate to the lights.

@Dan can sort out giving you a DIY tag and moving the thread into the DIY section

 

[matt_180]

Thanks, that's a relief as I couldn't think of how else I could do it.

The bit that made me question about the flex is that when looking for fan units, I found one that specifically said not to use a flex:

https://www.manrose.co.uk/wp-content/uploads/doc/FandWs/077546B.pdf

"These units are for fixed wiring only. A flexible cord must not be used. All wiring must be fixed securely and the cable to the fan should be a minimum of 1mm2 in section. All wiring must comply with current I.E.E. Regulations or local regulations if outside the UK."

I couldn't really think of why that would be as long as the amp rating was correct (can still clip the flex in place if they are worried about it being pulled).

Luckily there's plenty of others that don't seem to mention it at all...
e.g.

https://www.vent-axia.com/sites/default/files/409945_0.pdf

It does mention that 'The Fan should be provided with a local double pole isolator switch having a contact separation of at least 3mm.' which presumably is covered by the fact it's plugged in to a standard socket.

Sorry - I'm probably just over thinking this

 

[mainline]

Thanks, that's a relief as I couldn't think of how else I could do it.

The bit that made me question about the flex is that when looking for fan units, I found one that specifically said not to use a flex:

https://www.manrose.co.uk/wp-content/uploads/doc/FandWs/077546B.pdf

"These units are for fixed wiring only. A flexible cord must not be used. All wiring must be fixed securely and the cable to the fan should be a minimum of 1mm2 in section. All wiring must comply with current I.E.E. Regulations or local regulations if outside the UK."

I couldn't really think of why that would be as long as the amp rating was correct (can still clip the flex in place if they are worried about it being pulled).

Luckily there's plenty of others that don't seem to mention it at all...
e.g.

https://www.vent-axia.com/sites/default/files/409945_0.pdf

It does mention that 'The Fan should be provided with a local double pole isolator switch having a contact separation of at least 3mm.' which presumably is covered by the fact it's plugged in to a standard socket.

Sorry - I'm probably just over thinking this

As long as you ensure that the socket outlet is in fact double pole, as lots aren't. But there again safe isolation can be done by unplugging it.

 

[brianmoooore]

Strange instruction for the Manrose fan! I've used several of them, and the connection block, grip and entry grommet are most definitely more suited to flex than T&E. Always connected them with 0.75mm2 4C flex to an adjacent isolator, and will continue to do so.

 

[davesparks]

. Always connected them with 0.75mm2 4C flex to an adjacent isolator, and will continue to do so.

I do similar except I use a 4 pin plug and socket so that I can spend the minimum amount of time in a loft as possible, and it can be easily unplugged and removed for repair/replacement.