Extractor fan question

[Muddy Funker]

Hi guys, 

Question involving the humble bathroom extractor fan. 

I'm currently putting back together a ripped out bathroom which never had any extraction, I'm dealing with this now. 

I know the usual way is by linking this in with lighting circuit but are there any better options? To me it makes no sense as sometimes I'll want a shower and not have lights on, another time I might turn lights on and not be having a shower. 

I've been searching on Google and most questions about extractor fans involve everyone saying if you don't know what you're doing get an electrician. 

I'm aware of part p and building control and my obligations around it, this is my problem. 

Any nice solutions or does it always have to be linked with lights? 

Many thanks in advance. 

[Yellow Bear]

If you put the light switch external to bathroom you can put in a double unit with single feed to but separate returns to lights and fan.  Fan would normally have a permanent L/N/E and a switch feed from lights, all you are doing is putting the start signal on it's own switch and will still run-on on timer when fan is switched off.

Edited September 20, 2020 by Yellow Bear

[Muddy Funker]

Perfect that's a nice solution right there thanks. 

Would another idea be wiring fan to a pull switch and then having lights running off a pir type switch located in bathroom or is that not really a done thing? 

[Dave at kelton]

16 minutes ago, Yellow Bear said:

If you put the light switch external to bathroom you can put in a double unit with single feed to but separate returns to lights and fan.  Fan would normally have a permanent L/N/E and a switch feed from lights, all you are doing is putting the start signal on it's own switch and will still run-on on timer when fan is switched off.

Exactly what I have separately wired ceiling light and fan with external switching. Often have mirror light on rather than main light on a bright day and switch fan on separately.

[Diver One]

3 minutes ago, Muddy Funker said:

Perfect that's a nice solution right there thanks. 

Would another idea be wiring fan to a pull switch and then having lights running off a pir type switch located in bathroom or is that not really a done thing? 

Yes ,but it looks a 🐷 

pull cords are the work of the devil

 

another option is a fan with a built in PIR or better still a Humidistat

if using a ceiling fan make sure the instructions say ,"suitable for ceilings". A lot aren't and the bearings seize

[Muddy Funker]

Thanks all, yeah hate pull cords I like the sound of the double switch idea. 

Do people really have this many switches outside a bathroom? 

I've got a digital shower mixer so that has it's own spur, then I'll need a double light switch that (correct me if I'm wrong)then on the fan side has to go to a 3 pole isolator (another ******* switch). 

A lunar lander probably had less switches 😂

 

 

[Demonic69]

I'd go for PIR, you can get them pretty discreet and as long as you keep it out of the shower zone it could go almost anywhere. Couple that with a "silent" timed extractor and you've got a fan that works when you need it.

[Diver One]

Fit a DP secret keyswitch BEFORE the fan control switch

take feed to fan control switch through this key switch along with the neutral to the fan

killing keyswitch will isolate neutral to fan, feed to switch and therefore the switched output from switch as well. So the triple pole switch is not needed

all three switches can fit on a single Scolmore Click Mini grid plate system and they aren't expensive

[figgy]

Your making a lot of work just to not have a light come on with the fan.

All mine come on with the light and are timed. I just pull the light cord on and off fan works on timer without the light on simples.

[udderlyoffroad]

6 hours ago, figgy said:

Your making a lot of work just to not have a light come on with the fan.

This.  The extra cost of doing all this, even if you DIY, will take a long time to pay back through the saved electricity of not having the light on.  Also, remember it's not just you using the bathroom, try explaining all this significant others/kids/guests and see how often it happens as you would wish.  Frankly, "showering?  light on." is hard enough to enforce.

Remember, if you're going to do this and subsequently have it inspected, you'll need an isolator switch, and likely as not a fuse (the instructions of most fans call for one).

Finally, remember any kit you use in a bathroom has to have the right IP rating for the zone you intend to use it in.

 

[figgy]

Could use a pir and a light sensor to only bring the light on when dark enough. 

[Muddy Funker]

Thanks again everyone. 

Plenty to digest, it's an interesting one as a Google search opens up an absolute ton of previous threads of arguments on how best to proceed. 

It seems the requirement to step down to 3amp as many fan manufacturers request creates a minor headache. 

I've found a fused fan isolator but it only comes in a ****ty plastic version, no idea why you can't get alternative finishes? Maybe manufacturers will bring them out in future. 

Cheers for the advice 👍🏻

 

[udderlyoffroad]

20 minutes ago, Muddy Funker said:

It seems the requirement to step down to 3amp as many fan manufacturers request creates a minor headache. 

Grid switch, with the main fan+light switch, and a fuse holder for the permanent live supply to fan.

Comes in a variety of finishes.

Then run three core (Line, Switched Line, Neutral + CPC) up to the Isolator switch (above the door, keeps it out of eye level), and thence to fan and lights.