Bathroom fan rules.

[Alltheones]

I’m a electrician although it’s been a few years since I worked in the uk and I’m looking at cabling a bathroom fan in my extension I just want to get it right for the test the council is doing when I’m done.

I used to have to put the whole bathroom on a fused spur with a 3a then a fan isolator. The fan needs to run on a timer.

I really really don’t want a fused spur i don’t really want the isolator either, which is why I’m asking if it’s actually in the regs.

Can I get a fan that will be fine on the 6a lighting breaker?
Does the fan isolator have to be at roof height, can it be dropped to socket height so it won’t be seen in my room?
Again I don’t need to know how to cable this I’m just after any regs that might trip me up over this, I can about handle a fan switch near the ceiling but not that and a spur as I’m having a feature bulkhead and it will kind of ruin it.

 

[ericmark]

The rules are down loadable from a portal in Parts, not sure think part F? They do vary a little between Scotland, Wales, and England, with some requirements changing over the years, but if you have an opening window where people can look in when open, then no fan required.

There has never been a requirement for it to work with lights, a simple pneumatic timing switch is enough, think from memory 15 minutes run on, at one point if non opening window you had to be able to run fan without lights, but that requirement I think dropped, but may vary country to country.

I found building inspectors had their own ideas, the rules say nothing about where the window is, but my building inspector said because some one walking past could look into bathroom I needed a fan, since designed to remove moisture normally mounted high up, close to shower, but a building inspector does not need to follow rules, so even if following the rules you can mount 1 foot of floor, unlikely he would accept it, I seem to remember three parts of building regulations cover the bathroom fan, there is a requirement that it should not draw fumes into the home, so any fire which has an open flue (and open flue means drawing air from room not actually an open flue) can allow fumes into room if a fan causes a pressure drop, so how the air is replaced is also considered. (Part J)

Having had problems with a building inspector today very careful to submit full plans, if full plans show fan position and they are passed, then he can't change his mind latter.

In the main the isolator is so if the fan becomes faulty you can still use lights, you could have a double pole switch and fan completely independent from lights electrically just using same switch. But nothing in regulations to say must use a fuse connection unit (FCU) or isolator, in fact the winding of the fan are so thin unlikely even a 1 amp fuse would protect it, so rather pointless.

Part L may require heat recovery, and so may Part J it is really how pedantic the inspector is. Don't upset him, he is god. Of course Part P requires you to follow electrical regulations with RCD protection etc. I found getting the building inspector to accept my qualifications was a problem, he wanted me to get everything inspected at my expense by some electrician he would appoint, it would have cost more for the inspection than to do the job, make sure he knows you are doing the installation certificate and if not a scheme member that he is well aware your not a scheme member. Seem to remember a tick box on the application.

It was so much hassle working with building control, who never inspected at end of job, it was just a rubber stamp job, when I came to do a rewire I got a scheme member to do it, the inspector clearly did not want me to do my own electrics in Flintshire, but in Liverpool they could not have been more helpful. Cheshire between the two.

 

[Alltheones]

I don’t mind the fan so much it’s all the crap that has to go with it. If there are no regs stating height of isolator then that’s perfect as I’d rather it be low level without a fused spur.
My sotuation is a bit messed up as I have a part p thing from council for the rest of the house after I’m done but because I’ve had a extension I’ve a different building inspector although I’m hoping when he comes next week to check the builders stuff he just signs that off and the electrical falls back to my original notified works and they pass that after I’m done.

 

[Taylortwocities]

In my experience, BC will just look to see if there’s a fan installed and that’s the tick in a box. Never have seen one even turn it on, or time the over-run.

 

[Alltheones]

Cheers.

I’ve a flexi duct I’m going to run inbetween the fan and the soffit, should I try and wrap this in insulation to stop condensation?

 

[johnny2007]

Fan isolator can be anywhere outside the bathroom, I have mine hidden in a corner just outside the bathroom next to a single socket.
BC official will have their own interpretation of the regulations and sometimes are seriously in the wrong, but they feel better if you ask for their advice, so do it.