Extractor fan with fused isolator

[JohnW2]

When the fan is water logged with condensed liquid then the RCD might trip and then not be re-settable until after the fan has dried out. That said the fan the OP has is well designed and very unlikely have water reaching the electrics.

Indeed - and not only is that very unlikely to happen with a fan, but probably no more unlikely with a light fitting, light switch etc. - things for which there is no 'requirement' for an isolator.

Kind Regards, John

 

[JohnW2]

As for being a manufacturer's instruction, it is of no consequence to the fan (or anything else) whether it has an isolator, or even a fuse or an RCD (if wired correctly), so it must just be that the manufacturer thinks it is an electrical regulation requirement - in Britain.

Yep, that's probably about it - I certainly can't think of a more credible explanation.

Kind Regards, John

 

[bernardgreen]

and not only is that very unlikely to happen with a fan

Extractor fan blowing damp air and steam into the duct, that won't create water ?

 

[JohnW2]

Having said what I just have, It would be extremely simple for the OP to fit the 3 pole switch he has already bought - not using the fuse and making it clear that it is not used - next to the fan.

It would - if some point were perceived (in having the isolator at all) - I'm not sure that "complying with the manufacturer's instructions" would be a particularly good reason, if one was ignoring half of those instructions!

Kind Regards, John

 

[JohnW2]

Extractor fan blowing damp air and steam into the duct, that won't create water ?

Sure, but I was merely agreeing with you, when you said that "it was very unlikely that water would reach the electrics of an extractor fan" !

Kind Regards, John

 

[mjas]

My understanding was that to comply with UK regulations I need the 3 pole isolator switch to enable the fan to be isolated for maintenance. To meet the manufacturer's guideline I need the fuse. As correctly observed I was looking to comply with both so there is no comeback if anything did go wrong in the future. I very much appreciate all of your responses (and I never expected it to generate so much debate). Have I missed something(?) or am I fundamentally wrong with my understanding of the requirements, whilst accepting the guidelines may be overkill or pointless.
I think the installation I am replacing was probably installed non-compliant, although it has worked without issue for 10 years, and I am expecting that my 3 pole fused spur may only be appropriate with some fiddly wiring but I can do the replacement with new fuses and switches if necessary.
Regarding other comments, guidelines for positioning the extractor are provide to minimise any issues with condensation. Thanks for all of your feedback.

 

[winston1]

My understanding was that to comply with UK regulations I need the 3 pole isolator switch to enable the fan to be isolated for maintenance.

As has already been pointed out you are wrong. There is no UK reg saying you need a 3 pole isolator.

You can isolate it for maintenance at the CU just like you would for maintenance of one of the many lights around your house.

 

[333rocky333]

I once had a timer fan where the lights were on a 10 amp circuit, i felt the easiest option was to fuse both feeds, if its up in the loft it will be out of sight.
You could get a dual box, use the switch/fuse what you have and buy an unswitched Fcu for the second supply

 

[AndyPRK]

I would think 99% of new houses built in the last 20 years in the uk have fan isolators.

I would say approx none of them have fuses!

Personally I like the isolators. So I can turn the fan off in the deep winter. Or just winter. Nice silence.

 

[333rocky333]

As has already been pointed out you are wrong. There is no UK reg saying you need a 3 pole isolator.

You can isolate it for maintenance at the CU just like you would for maintenance of one of the many lights around your house.

A fan is NOT a light it requires Mechanical maintenance and some fans are further covered by the scope of BS EN 60204, if so isolating at the Cu may not satisfy 537.3.2.4, maybe you should update yourself with section 537.3

 

[EFLImpudence]

What about the NOTE below 537.3.2.2?

 

[winston1]

I don't know what your numbers mean, but "There is no UK reg saying you need a 3 pole isolator."

 

[EFLImpudence]

I don't know what your numbers mean,

 

[JohnW2]

I once had a timer fan where the lights were on a 10 amp circuit, i felt the easiest option was to fuse both feeds, if its up in the loft it will be out of sight. You could get a dual box, use the switch/fuse what you have and buy an unswitched Fcu for the second supply

What do you mean by "both feeds" and "the second supply"?

If you are perhaps talking about separately fusing the L and S/L feed to the fan then, as EFLI pointed out, that introduces a theoretical hazard - if the fan stopped working because a fuse in the permanent L feed blew, if one then opened up the fan to investigate (forgetting to operate the isolator, since the fan was not running), one could be 'surprised' (or worse) by a live S/L if the light was on.

Kind Regards, John

 

[AndyPRK]

It’s very siqmilar to any electrical equipment isn’t it.

Make sure it is fully isolated first