Bathroom extractor fans and 3 pole isolation: A source of much controversy

[Estimator]

I’m not taking a “side” in this rather heated discussion, feeling that, as with a lot of the content in the BGB, isolation is left rather open to interpretation, by different people.

Here are a few extracts from various manufacturers installation leaflets. Apologies if the images don't turn out quite right, it's my first attempt at this...

Greenwood Airvac – Unity CV100



Greenwood Airvac – EL100, EL150U, EL150 & EL150SCPC



Vent Axia

Manrose

Xpelair




Out of the 4 manufacturers only one mentions a 3 Pole isolator and this is in addition to the suitably fused connection unit, which are all double pole. I think, if you lock the fuse carrier open, then it would be unlikely that some one would switch the spur on, maybe causing you a problem with the RCD, if you are changing the fan.

On the same subject, by my user name you can tell I'm primarily, nowadays an estimator, but I am time served and had a break from office work for a while, a few years ago and “went back on the tools”. I price a lot of jobs, mostly commercial with some apartment blocks and a lot feature extract fans fed from local lighting circuits and it’s 50/50 on whether a FCU or both a FCU and fan isolator is required. Most of the jobs are pre-designed by "experts"

 

[Estimator]

since when does a domestic bathroom fan require D.P. isolation ?

Since the manufacturers say it should?

But only if the circuit protective device is bigger than 5A? Sorry that's separate fusing...

see my previous post...

I'm not saying you need DP isolation, just what the manufacturers say...

 

[Stroppy]

Stroppy, what make is this? Never seen one before and not in my wholesaler, I do use on line and may have never picked this up being a small catch/ screw on the bottom."

This one is a Newlec, and from my google search for the phrase "triple pole isolator with lock" it seems MK do one as well. They come with a little key to operate the locking device, which I imagine disappears without trace after 10 minutes of the installer leaving the building

 

[supertoad]

a fan on a timer needs a permenant feed/sw feed/neutral, i recon that the hse would require safe isolation[ie; not working in the dark, with half the lights in the house off, and a torch in your mouth-the "regs"are a BS standard and the hse requirments tend to be legaly binding-i think

 

[HandySparks]

i recon that the hse would require safe isolation[ie; not working in the dark, with half the lights in the house off, and a torch in your mouth

So what do you use for illumination when you're working on a lighting circuit?

(Not saying that being able to leave the lights on isn't convenient.)

 

[BrianDB9]

Freaking heck i'm gonna get my hard hat on ! Thought it was a forum not a boxing ring lol

Just had an issue about ventilation fans in bathrooms and looks like my solution is going to be to fit a DP secret key switch with fuse on a grid switch with the faceplate engraved "Bathroom Ventilation" it's going to be located in the adjacent store cupboard and wired onto the lighting circuit so tenants are disuaded from turning the CB off.
The fan has humidistat and pull cord overide so no issues with over run.

 

[supertoad]

not telling! but good point,[its the desighn that bothers me]-think i mey have mispelt desighn

 

[Guest55]

my solution is going to be to fit a DP secret key switch with fuse on a grid switch with the faceplate engraved "Bathroom Ventilation"

excellent idea imo , thumbs up

 

[Stroppy]

So what do you use for illumination when you're working on a lighting circuit?

Head torch.

Or work live so you can leave a light on.

 

[ontimeelectics]

Great info. Copied and pasted into my archive file.