Extractor fan with fused isolator

[JohnW2]

I see nothing to suggest that the fused isolator he has bought is the best option.

Well, if he really wants to comply with all the manufacturer's instructions, the alternative would be to EITHER have both an FCU and a 3-pole isolator OR to do as the Manfrose diagram suggested (have just a DP FCU) and thereby lose any conceivable advantage of having an isolator - and I'm not sure that either of those would necessarily be any better an option.

Kind Regards, John

 

[winston1]

The old fan did work with a timer, I photographed the connections but it was neither isolated or fused.

It had both. In your CU which is all that is required.

This looks like yet another case of manufacturers instructions that are wrong.

 

[JohnD]

I'm not sure that either of those would necessarily be any better an option.

a lot simpler to install and understand, though

for the OP, and whoever comes across it in future.

 

[AndyPRK]

Arh yes, I noticed in October that click were making these:

https://www.diynot.com/diy/threads/fan-isolator-fused.510693/#post-4237415

 

[JohnW2]

a lot simpler to install and understand, though ... for the OP, and whoever comes across it in future.

It is hardly any different from 'normal' (the only difference being that the L feed to the light switch comes from the fuse, rather than the CU), and virtually no different from having an FCU and isolator (in which case the L feed to the light switch comes from the FCU, rather than the CU).

I would dare to suggest that anyone who could not work that out probably should not be 'fiddling' with the wiring, anyway.

In any event, if he stuck with the same arrangement as with the OP's previous fan (no fuse and no isolator), then he could use the previous cable/wiring, and that would be the simplest solution of all!

Kind Regards, John

 

[mjas]

Unfortunately, I tend to agree with John D. The existing cable layout may dictate whether I can work around it.

 

[JohnD]

Unfortunately, I tend to agree with John D.

Fortunately.

 

[JohnW2]

Unfortunately, I tend to agree with John D. The existing cable layout may dictate whether I can work around it.

That might be true in your case - I've said more than once that the practicalities depends upon your 'spaghetti'!

However, as I've said, if it is your intention to provide both fusing and an isolator, whilst also retaining the one 'just-about-arguable' benefit of having an isolator, then you're going to have to have an FCU as well as an isolator, and I would have thought that any problems you have in relation to cable layout/'spaghetti' would probably be at least as great in relation to wiring that FCU as it would be if you utilise the fuse module in the 'isolator' you have. However, maybe I'm wrong!

Kind Regards, John

 

[EFLImpudence]

I don't think that keeping on repeating a 'just-about-argueable' benefit is of any benefit.

What happens when he wants to mend the light - or connect the new fan?

 

[JohnW2]

I don't think that keeping on repeating a 'just-about-argueable' benefit is of any benefit.

You're probably right, but what do you think I (or anyone) should say, given that the OP appears to want to 'comply' with the manufacturer's instructions.

If, as my inclination, I dismiss the 'just-about-arguable' benefits, that means no isolator, and I think that the argument for a fuse is probably even weaker - so should I be advising the OP to ignore the MIs (as winston has done)?

Kind Regards, John

 

[EFLImpudence]

I just don't think anything is instructed/intended for the purpose of the light remaining on. It is not considered for any other occasion.
Someone probably commented once that he could work on the fan with the light on because it had an isolator so it has passed into folk lore.

Boilers have to have an isolator according to similar instructions and plumbers; it is never mentioned that this is so that the light will remain on -when on the lighting circuit.
When on the ring circuit, it might be handy to be able to use the vacuum cleaner.

 

[JohnW2]

I just don't think anything is instructed/intended for the purpose of the light remaining on. It is not considered for any other occasion.

You're probably right - but I can think of no other rational reason for requiring an isolator, can you? Once one has dismissed that possibility, I see it as no different from requiring an isolator for a light fitting "so that one can work on it".

However, you didn't answer my question - which was not intended to be rhetorical. Do you think we should follow winston's example by effectively advising people here to ignore the manufacturers' 'requirement' for a fan isolator (and the fuse, come to that)?

Kind Regards, John

 

[EFLImpudence]

You're probably right - but I can think of no other rational reason for requiring an isolator, can you?

No, but (nearly) all similar instructions for appliances state one is required - in Britain - showers, cookers, boilers etc.

Once one has dismissed that possibility, I see it as no different from requiring an isolator for a light fitting "so that one can work on it".

I suppose light fitting instructions are one of the few which do not require an isolator, now you mention it.

However, you didn't answer my question - which was not intended to be rhetorical. Do you think we should follow winston's example by effectively advising people here to ignore the manufacturers' 'requirement' for a fan isolator (and the fuse, come to that)?

I would, as I have done, tell them it is not electrically required nor a regulation.

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.

 

[bernardgreen]

no other rational reason for requiring an isolator

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.

 

[EFLImpudence]

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.

Fitting a fuse would be more involved and of no benefit on the light circuit - albeit with a 10A MCB.