3 amp fusing for extractor fans

[chloebear]

:banghead: Hi All,
Just had my NicEic audit and have been picked up on not fusing extractor fans down to 3amp. Normally the installation of extractor fans would come off a lighting circuit via a 3 pole isolator to the fan, unless the fan has been installed utilising a cct other than lighting I would not use a fused spur for the fan. If all 4" fans have to be fused 3amp this will mean installing a fused spur and a fan isolator for each fan?
Also most fans have 2x lives - Permenant & Switched - so which one should be fused, or do we now have to fuse both??

Coments and ideas would be appriciated.

 

[malcolmsanford]

The good old manufacturers instructions strike again.

To my mind if your coming off a lighting circuit I can see no possible reason why on earth in today's world why you need a 3amp cartridge fuse in the circuit.

Most new fans are double insulated and so give protection that way, and if a fan is going to overload to an extent that it will blow a cartridge fuse before the protection device at the CU then we have real problems.

There was a scare story a few months back where apparently a fan caught fire and caused damage and it did not disconnect the lighting protection device, I find that unless this had been a BS 3036 fuse that had 15/32 amp fuse wire fitted to it hard to believe.

I suppose the 3amp fuse rule is a way to ensure that if a DIY'er did the above scenario then the situation is covered.

 

[kamkam]

Main feed for bathroom or utility or loo with fan into spur above door feed out to other rooms (if any) and load side of spur via 3 amp fuse for bathroom then wire as normal as the whole of bathroom circuit is fused down (example - 6 35watt spots , shaver socket, fan not gonna draw more than 2amps)
Yes ugly spur next to isolator but there you go... you can always not fit a isolator for the fan if the room has a window.

 

[DaveyD]

Yet, how many times have you found 15a fuse wire in a 5a holder to solve a problem. I did last week. So fuse wire and a 3 amp fuse can be changed buy the customer in a fault. Changing a CB from 6a to 16a is a lot more difficult

 

[telectrix]

well, i've just fitted a fan in our new shower room. no isolator, no 3A fuse. and it's independent of the bloody light.

 

[DaveyD]

well, i've just fitted a fan in our new shower room. no isolator, no 3A fuse. and it's independent of the bloody light.

Shocker! Is it connected?

 

[stuart569]

Main feed for bathroom or utility or loo with fan into spur above door feed out to other rooms (if any) and load side of spur via 3 amp fuse for bathroom then wire as normal as the whole of bathroom circuit is fused down (example - 6 35watt spots , shaver socket, fan not gonna draw more than 2amps)
Yes ugly spur next to isolator but there you go... you can always not fit a isolator for the fan if the room has a window.

So you're saying use a switch fuse feeding the bathroom light switch then from there as norm to your three pole isolator? So three switches? That's bloody ridiculous there must be an easier way!!

 

[DaveyD]

Is there such a thing as a three pole isolator that is fused on S/L and L ?

 

[telectrix]

Shocker! Is it connected?

works perfectly. switch on lights, switch on fan. on exit, switch off both. fan overruns. nothing unsightly, nothing complicated. lights and fan on dedicated circuit from CU on a 3A MCB. ( there's also an RCD somewhere in the CU)

 

[telectrix]

and i've run a neutral to the switch position. that's crucifixion 4 sure

 

[Richard]

Is there such a thing as a three pole isolator that is fused on S/L and L ?

Would that be dangerous though? as It may appear dead if one fuse had gone, yet it would still be live.

Edit: and no i'v never seen one

 

[sjm]

IMHO the problem arises because, as has been said, the manufacturers instructions require 3 amp fusing. However if you use Vortice fans their instructions only require a multipole isolation switch for maintainance.

 

[kamkam]

So you're saying use a switch fuse feeding the bathroom light switch then from there as norm to your three pole isolator? So three switches? That's bloody ridiculous there must be an easier way!!

And your solution is???

 

[ezzzekiel]

Did the man. Instructions state it must be fused down or was this just the usual niceic inspectors making there mouths go as usual

 

[jeremy]

Shouldn't dedicated appliance circuits be fused down to the lowest possible fuse rating? I seem to remember this but may be making it up!

 

[telectrix]

but a fart fan ain't on a dedicated circuit.

 

[jeremy]

If it's on a an fcu, is it then on it's own circuit?. I'm missing something, aren't I?

 

[GLENNSPARK]

Yet, how many times have you found 15a fuse wire in a 5a holder to solve a problem. I did last week. So fuse wire and a 3 amp fuse can be changed buy the customer in a fault. Changing a CB from 6a to 16a is a lot more difficult

Found some 2.5 cpc once...lol....

 

[GLENNSPARK]

Would that be dangerous though? as It may appear dead if one fuse had gone, yet it would still be live.

Edit: and no i'v never seen one

Come on....ever heard of steinels mate....always prove and test for dead before starting owt mate.....

 

[telectrix]

If it's on a an fcu, is it then on it's own circuit?. I'm missing something, aren't I?

nope. a circuit starts at the CU. if you fit a FCU to a circuit, then whatever is fed by that FCU is part of the original circuit. it is not a new circuit.