Bathroom fan: do UK regs require connecting via lighting circuit?

[Electro-tech]

As far as I know, it always has, but of course Document F changes over time.
Current regs, for a refurb of an existing bathroom, are that if there was no fan before, then there's no obligation to fit one. If there was one there before, it needs to be retained or replaced by one at least as effective.

So are we expected to fit a fan & test the flow rate & notify the LBC with a cert or is this for larger ventilation systems.
The regs are getting that mad that they have brought out Document O for overheating .

 

[brianmoooore]

Most times I connect the fan with the light , but with a lot of posh bathrooms / en-suites I am doing they have dimmers and multiple switching for sets of lights.
So I then lean toward a hard wired fan with either a built in PIR or built in humidistat

It's a long time since I wired a bath/shower room with just one light, so I either wire the fan with one set of lights (they can just switch on the other set if they don't want the fan) or wire the fan on its own switch with a neon.

 

[LastManOnline]

I don't have one in my bathroom , I just open the window

A far more effective option.Up until relatively recently most standard 4" fans were very poor value for money

 

[telectrix]

I don't have one in my bathroom , I just open the window

common sense beats technology every time.

 

[brianmoooore]

common sense beats technology every time.

Until the technology advances to the point when an open window flows air in one direction only, I'll stick with an extractor fan for at least six months of the year.

 

[telectrix]

Until the technology advances to the point when an open window flows air in one direction only, I'll stick with an extractor fan for at least six months of the year.

simples solution. increase the pressure inside the barthroom/bog so that the airflow is to the outside. a few good farts should sudfice.

 

[brianmoooore]

The 'few good farts' are a major part of the problem, according to my missus.

 

[telectrix]

The 'few good farts' are a major part of the problem, according to my missus.

well, it's just jealosy. women can't fart as much as they can't keep their gobs shut long enough to build up the necessary pressure.

 

[Mike Johnson]

The Manrose remote Humidistat will work even if the light is off, a light can be wired across the off side of the single switch and mains neutral: https://myshop.s3-external-3.amazon...mages.Ventilator-vochtsensor-elektronisch.pdf

 

[LastManOnline]

. a few good farts should sudfice.

I was afraid he had retired? Been missed.
Any disquite about Tel,s state of health can now be fully dismissed.I,m not sure what type of barometer the hospital staff used to gauge his recovery ,but readers on here always knew that when he once again would discuss with gusto the topic closest to his heart (no pun intended.And no ,its not electrics), that we could state with confidence "He,s back!.Normal service has resumed"

 

[telectrix]

still here. new laptop as windoze no longer supporst window 7. buggers. got to get it all working. and as regards my state of health. getting better day by day. long as i caN DRIVE TO THE LOCAL SPAR FOR BEER AND smokes.......

 

[MisterProzilla]

The Manrose remote Humidistat will work even if the light is off, a light can be wired across the off side of the single switch and mains neutral: https://myshop.s3-external-3.amazon...mages.Ventilator-vochtsensor-elektronisch.pdf

That's the exact remote humidistat I bought thinking it should be able to work, as you say, even when the light is off.

I queried it with the electrician - he says that the fan will always work with the light regardless, then run on, until humidity is gone.
I don't know, maybe my expectations were back to front about how they actually work - I thought they woul detect moisture THEN come on, rather than having to be turned on then use the stat to turn itself off. If that's the case then this remote stat is doubly redundant - no point in having the sensor if you have to turn it on manually anyway, and then no point in having the run-on timer if it's going to use the sensor to decide when to turn off.

 

[nicebutdim]

That's the exact remote humidistat I bought thinking it should be able to work, as you say, even when the light is off.

I queried it with the electrician - he says that the fan will always work with the light regardless, then run on, until humidity is gone.
I don't know, maybe my expectations were back to front about how they actually work - I thought they woul detect moisture THEN come on, rather than having to be turned on then use the stat to turn itself off. If that's the case then this remote stat is doubly redundant - no point in having the sensor if you have to turn it on manually anyway, and then no point in having the run-on timer if it's going to use the sensor to decide when to turn off.

The humidistat is a switch that operates when set humidity threshold is crossed.

The humidistat you have bought can be wired through a light switch, to operate when light is switched on and continue to run until overrun timer setting has passed. If set humidity threshold is exceeded it will continue to run until such times as humidity decreases below set threshold.

The above is dependant on a permanent live supply to stat, alongside switched live feed to light. Without that permanent supply, the fan is isn't going to run when the light is switched off.

It is equally possible to wire the stat through a switch completely independant of lighting.

Please note that manufacturer specification for your stat stipulates that it must be fused at a maximum of 3A and wired through double pole isolation (3 pole if wired through lighting).

 

[Mike Johnson]

That humidistat will switch on whenever the humidity reaches or exceeds the threshold set on the dial irrespective of the light on or off, just turn the humidistat dial down until it comes on, you probably have it set too high.

 

[nicebutdim]

That humidistat will switch on whenever the humidity reaches or exceeds the threshold set on the dial irrespective of the light on or off, just turn the humidistat dial down until it comes on, you probably have it set too high.

Read through the OP.