Fan Isolator Fused

[AndyPRK]

Remember all those arguments (I mean discussions) about following the manufactures instructions about installing a 3A fuse when fitting a bathroom fan?

And that no body did, cus it was feed from a 6A MCB

Well it seams click listened and now make one.

They leave the fuse connections for you to decide.
And very oddly supply a 13A fuse

https://www.ebay.co.uk/itm/Click-Ex...649610?hash=item3b1bdeb10a:g:kr8AAOSwPSxbVK~m


Also make one with a locking wheel

https://www.ebay.co.uk/itm/Click-Po...713676?hash=item3637c2498c:g:cOYAAOSwmtNbWZiD


Also make an isolator switch + normal switch (but no fuse)

 

[ericmark]

Have you looked at the wire used to wind a bathroom fan? It is extremely light, and should the fan stall then even with a 1A fuse the fan wiring will burn out before the fuse, so the fuse for the fan supply is to protect wiring, or could maybe allow the fuse to rupture before the main protective device so if supplied from lights 1A fuse may blow before the B6 MCB, however personally I think that is unlikely, maybe lights should be fused at the consumer unit, so the bulb internal fuse or fan fuse blows first, but we don't, we fit MCB's.

However it is wired independent so although switch and fuse are on the same plate, it does not mean they supply the same item. The whole idea of the three pole switch was you have a permanent and switched line so unless two fuses, it does not help, if supplied from sockets, then you can put fuse before the split to switched and permanent line which means a double pole light switch so lighting power is not used for fan.

The requirement where there is natural light to be able to switch on fan without light also means double pole light switch. I am lucky my house has opening windows in bathroom so in theory fan optional extra, however the building inspector said since with windows open some one walking to back door could look into the bathroom, he insisted a fan was fitted. Waste of time as always switched off on isolator.

So first glance looks good, but with single fuse how would you wire it?

 

[AndyPRK]

I did note the problem only having 1 fuse.

I know which one I would put it in though, if I was using such an item

 

[333rocky333]

One i made earlier

 

[333rocky333]

...]

 

[ericmark]

Can't remember how the one here is wired, but is there really any need to switch the neutral? Always used a fan isolator as it has the label fan on it, I would guess the supply from light carries no current, so only permanent line needs fuse? But never tested it.

 

[EFLImpudence]

No, but a fan might have two line feeds.

 

[JohnW2]

One i made earlier

If those two fuses are in the permanent L and switched L feds to the fan (via the isolator), would it not have been possible to do a little tweaking to the wiring so that a single fuse could have been used?

I know that it would take a bit of an idiot to come to harm as a result, but I'm not totally comfortable with having two (potentially) live feeds to something with each feed being separately fused. A bit like the situation with a fuse in the neutral, it means that one fuse can blow (and the item stop working) but with live conductors still present at the item.

Kind Regards, John

 

[ban-all-sheds]

And that no body did, cus it was feed from a 6A MCB

And therefore the fuse was not needed.

Well it seams click listened and now make one.

It's another stitch-up.

They leave the fuse connections for you to decide.

What they have made is something with a function which anybody could have done using an FCU and a fan isolator.

I wonder just how many people didn't install the FCU because that was simply too much work. They were happy to install the fan, happy to run the cables, happy to install the isolator, but were overwhelmed by the task of installing a second accessory?

https://www.ebay.co.uk/itm/Click-Ex...649610?hash=item3b1bdeb10a:g:kr8AAOSwPSxbVK~m

I love the use of plastic in two different colours.

 

[ban-all-sheds]

If those two fuses are in the permanent L and switched L feds to the fan (via the isolator), would it not have been possible to do a little tweaking to the wiring so that a single fuse could have been used?

Yes - have the fuse before the switch which controls the fan. If that's a light switch replace it with a DP one.

Do those and you find that not only do you now only need one fuse, you don't need the fan isolator if you use a switched FCU.

 

[ban-all-sheds]

Doesn't look as if the flex to the fan is that small...

 

[JohnW2]

If the cable between light fitting/rose/JB/whatever to Rocky's 'dual fuse unit' were changed to 3C4C+E, then hardly any change would be needed (other than loss of one fuse). In particular, the existing (presumably SP) light switch and its wiring could still be used.
Edit: typo corrected.

 

[ban-all-sheds]

1. It must already be 3C+E.
2. Surely the whole point is to fuse both permanent and switched line...

 

[JohnW2]

Apologies - a typo (now corrected). I meant to type 4C+E (hence necessarily flex, although there's nothing wrong with that). That would facilitate fusing of both the permanent and switched L with one fuse (since the light switch would be fed from downstream of the one fuse).

 

[ban-all-sheds]

How would changing the cable between the light fitting/rose/JB/whatever to the dual fuse unit mean that the light fitting/rose/JB/whatever would no longer be directly connected to the lighting circuit?