Is a bathroom fan isolation switch essential

[chriselevate]

We shortly having a new bathroom fitted and I wondered if an isolation witch for an extractor fan was essential? The en suite doesn't has one so I wondered what the regulation/advice on here was for it.

Thanks

 

[bernardgreen]

Useful when working on the fan with the light on to see what you are doing.

Useful if the fan goes faulty and trips the lights MCB or RCD

 

[chriselevate]

Got you. Not regulation but very helpful? Is it most common to have this isolation switch above the entrance door to the bathroom? If it has an overrun timer I’m right in saying it’ll be 3 core and earth from the light to the isolation switch and the same from the isolation switch to the fan?

 

[bernardgreen]

Yes 3 core plus earth,

Neutral, Permanent Live and Switched Live

 

[chriselevate]

Most of these switches are located about the bathroom door? You wouldn't really put it anywhere else like under the light switch at low level etc?

 

[bernardgreen]

located about the bathroom door?

Avoids little people turning the fan off by accident. Also shortest cable route from isolator to ceiling rose / lamp.

 

[chriselevate]

Yes very true. With spots lights going in... am I right in saying there little value in keeping the lighting feed to the room in the centre? It’s better to have it near where it comes into the room and then all the spots chain from there?

 

[JohnW2]

Got you. Not regulation but very helpful?

There will be varying opinions about "very helpful". Once every few years one might want to 'work on the fan' (usually to replace it), and, if there isn't daylight in the room, then an isolator would enable the lights to be left on whilst one did the work. However, that's a bit of a luxury, which is not available when 'working on the lights' themselves!

Extractor fans would very rarely trip an MCB, and most simply cannot trip an RCD other than in extremely unusual circumstances, so most people will never see either happen in a lifetime - so, again, having an isolator to use (until the fan is repaired/replaced) if that ever does happen would be somewhat of a 'luxury'. ... and, of course, connections within switches/isolators have been known to become loose, leading to problems (and theoretically possibly even fires) that could not happen if one did not have an isolator.

I would therefore suggest that one probably has to think a bit before deciding that a fan isolator really is "very helpful".

Kind Regards, John

 

[Taylortwocities]

Yes very true. With spots lights going in... am I right in saying there little value in keeping the lighting feed to the room in the centre? It’s better to have it near where it comes into the room and then all the spots chain from there?

Up to you. My usual method is have a deep (47mm) box for the isolation switch. At this point you’ll have
L, N, Switched L and earth. From this point you also connect the cable that goes to your lights. Sorted.

 

[blup]

It's also helpful to be able to isolate the fan if it is not needed when turning the light on, for example in the summer when normal ventilation through an open window suffices; or if the noise it makes is an unwanted distraction.

Blup

 

[securespark]

I have a TP isolator next to the en-suite light switch.
This means Mrs Secure can reach it when she wants the light without the fan.
Apologies, blup. I did not see your post.

 

[JohnW2]

It's also helpful to be able to isolate the fan if it is not needed when turning the light on, for example in the summer when normal ventilation through an open window suffices; or if the noise it makes is an unwanted distraction.

I agree that some people might want such functionality (although it is amazing how rarely bathroom windows are opened, even when openable - maybe due to fears about neighbours with binoculars ). However, if there is an easily-accessible isolator, and particularly if it is often used at night (to avoid fan noise), there is a serious risk that people will frequently forget to switch it back on (so that the fan comes on 'when needed') - and I imagine that some might even argue that having such a 'functional' switch could violate building regulations if there was no openable window and hence the fan represented the only significant means of ventilation.

In any event, if it is decided that such a 'functional switch' is wanted, it can be achieved with a simple single-pole switch (maybe a 2-gang one in combination with the light switch - similar to secure's photo) - it does not need a 3-pole 'isolator'.

Kind Regards, John

 

[plugwash]

Fan isolators always struck me as a bit silly, over-designed for a functional switch, under-designed for an isolator.

Others may disagree with me but I would not work on a fan that was only isolated by a typical "fan isolator".

 

[JohnW2]

Fan isolators always struck me as a bit silly, over-designed for a functional switch, under-designed for an isolator.

Indeed. If I subscribed to the reasons commonly given for having them, I suppose that, in my (several) rooms which have multiple wall lights and/or uplighters, I would have an isolator for each one, so that I could 'work on' in the light provided by the others!

Kind Regards, John

 

[ban-all-sheds]

I would therefore suggest that one probably has to think a bit before deciding that a fan isolator really is "very helpful".

I would also suggest that one probably has to think a bit before deciding that spotlights are a good way to light a bathroom.

Seriously, Chris, have you?

Have you thought about how many you'll need, and why it is so many?
If there's a bath, have you thought about how pleasant it will be lying in it looking upwards?
Have you thought about the evenness, or not, of the light levels?
Depending on what's above the bathroom, have you thought about all of the thermal insulation and sealing problems?