Fusing down of extractor fans

uksparks · May 8, 2015

Hi,

I have a question I would like to put to you to see who does what really.

The majority if not all manufacturers state something about the fan must be fused down to 3A...

Ok, scenario...

You have a bathroom, 6A light circuit, the light can either be switched at pull cord, light switch outside or the light fitting.

The customer says they want an extractor fan with Timer.

Option One
Do you just fit a fan in the ceiling / wall, and connect it off the light circuit straight to it and think nothing of it? This would be a permanent live supply and switched live.

Option Two
Do you fit a fan, and put a 3A fuse on the permanent live only? Leaving the switched live on 6A, also leaving the fan with the possibility of a blown fuse scenario but also having a live supply to it. You also fit a 3 pole fan isolator.

Option Three
Do you fit a fan, and put a 3A fuse on the permanent live supply to the light, then use that for the live for the fan, and the switched side of the light for the switched live etc. You also fit a 3 pole fan isolator.

Just to add to this
On top of these three options, lets say this is downstairs, no loft space etc, brick walls. You need to put a 3 pole isolator somewhere, where do you put it? Do you surface mount it in a box? Do you use a 3 pole pull switch on the ceiling? But hang on, where do you then put the 3A fuse? Do you not bother? Do you put in on the surface or ceiling?

Just wondering what others do as have been having this conversation with a couple of people. I also rang Manrose about this about putting a 3A fuse across the switched live too, they said, although preferable, it only really needs it on the permanent live.

NDG Elecs · May 8, 2015

happyhippydad said:
Could you expand on that a little GayOwl?

I think you're referring to 134.1.1?

If you are then I can see the difference in the wording of the reg compared to the BGB, however..

"The Installation of electrical equipment shall take account of the manufacturers instructions"

Does that still mean we HAVE to follow MI's as in the previous 134.1.1 or does it mean we can now give it 'consideration', and if we deem the install to meet all other regs and to be safe we do not have to follow MI's?

I think Richard summed it up nicely. I interpret it as giving it consideration as you say. I had a issue with some MI's a while back. Can't recall the full details but it was an oven and related to the cable they stipulated should be used; I think they said T&E should be used or they said 6mm cable should be used on a 2kW oven! I opted for a HOR type cable to connect the oven instead if I recall correctly. I noted this as a departure on the cert. I suspect we are meant to still note such departures, but we are not now considered to be breaking the regs by doing so.

Neil

NDG Elecs · May 8, 2015

Leesparkykent said:
Vortice and silavent are a few.

Hi Lee,

The text on that Silavent gumph does say 'suitably fused' mate! Personally I rarely use a FCU on them...triple pole isolator yes.

Leesparkykent · May 9, 2015

TheGayOwl said:
Hi Lee,

The text on that Silavent gumph does say 'suitably fused' mate! Personally I rarely use a FCU on them...triple pole isolator yes.

It says suitably fused, in accordance with IEE regulations though. I would take this as the CCC of the cable connecting the fan should be sized according to the OCPD. No where in the regs does it say a fan must be fused to 3amps.

NDG Elecs · May 9, 2015

Leesparkykent said:
It says suitably fused, in accordance with IEE regulations though. I would take this as the CCC of the cable connecting the fan should be sized according to the OCPD. No where in the regs does it say a fan must be fused to 3amps.

Fair play. Just noticed it and couldn't resist! :smile5:

Paul.M · May 9, 2015

Totally agree with the above posts. Only local isolation needs to be provided for a fan (when fed from the lighting circuit on a 6-10A MCB in 1.0-1.5mm). The 3A bit from the manufacturers is just covering their backsides.

Andy78 · May 9, 2015

I have never provided a 3A fuse for any fan I have ever fitted and never will regardless of instructions. As Richard says, a lot of instructions need to be viewed and digested with a large pinch of salt. A huge proportion of MIs are mere buttock covering documents, often provided for a range of appliances/equipment and not relevant to the model in your hand. Use your nowse and distil the wheat from the chaff.... this applies to all guidance offered in written or verbal form !

HappyHippyDad · May 9, 2015

TheGayOwl said:
I think Richard summed it up nicely. I interpret it as giving it consideration as you say. I had a issue with some MI's a while back. Can't recall the full details but it was an oven and related to the cable they stipulated should be used; I think they said T&E should be used or they said 6mm cable should be used on a 2kW oven! I opted for a HOR type cable to connect the oven instead if I recall correctly. I noted this as a departure on the cert. I suspect we are meant to still note such departures, but we are not now considered to be breaking the regs by doing so.

Neil

I think that was a good idea to note it on the cert as it shows you have given it consideration. Although, I suppose it's not actually a departure from the regs as the regs state 'take into account', you have taken them into account and made an informed choice to use HOR cable (which lots of other MI state to use!). So really you have still followed the regs!

NDG Elecs · May 9, 2015

happyhippydad said:
I think that was a good idea to note it on the cert as it shows you have given it consideration. Although, I suppose it's not actually a departure from the regs as the regs state 'take into account', you have taken them into account and made an informed choice to use HOR cable (which lots of other MI state to use!). So really you have still followed the regs!

This was pre AMD3 mate, so technically I still should have blindly followed the MIs!

chloebear · May 13, 2015

Click also make fused fan isolator that looks the part. single gang

stevey1983 · May 13, 2015

Just use a 3A MCB or RCBO for that circuit. protected then without all the fuss

LankyWill · May 19, 2015

ive probably fitted close to 1500 fans of various brands, greenwood, vortice, vent axia etc and have never fused them down. These are all of course on new build homes and wired via 3 pole isolator. Never had an issue and sleep fine at night. Just dont over think it.

onions1066 · May 19, 2015

I've not read all the way back but if it says it in the manufacturer's instructions why wouldn't you fuse it down? I fuse all fans down and code un fused fans as a code 2 on an eicr.

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onions1066 · May 19, 2015

Each to their own i suppose

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Leesparkykent · May 19, 2015

onions1066 said:
I've not read all the way back but if it says it in the manufacturer's instructions why wouldn't you fuse it down? I fuse all fans down and code un fused fans as a code 2 on an eicr.

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Do you work for BG? Lol