Bathroom extractor fan without fuse

[haptism]

Hi, anyone know a make/model of small bathroom extractor fan that does not (according to manufacturers instructions) need to be fused down ? Thanks

 

[Midwest]

You will get posts arguing that difference between a 3amp fuse and 6amp mcb would be too close to call. But presumably you have a TP & N isolator? You could fit a Click Scholmore3 pole fused isolator; Excel 3 Pole Fused Fan Isolator Switch - White | QVS Electrical Wholesalers - http://www.qvsdirect.com/excel-3-pole-fused-fan-isolator-switch-white?utm_source=google&utm_medium=googleshopping&utm_campaign=googlebase&gclid=CKCjh7-B_c8CFUONGwodFNcJyw

 

[Richard Burns]

For instance: Vent axia silhouette, Grenwood fans (if fitted to 5A lighting circuit), Envirovent silent.

 

[westward10]

Hagar and I think Wylex produce 3A mcbs.

 

[Taylortwocities]

I think that the makers put an FCU (with a 3amp fuse) in their diagrams to cater for where the fan is powered from a ring final and the fan and the connecting wiring need to be protected from a fault current limited only by a 32amp MCB.

IMO there is no need to 'fuse down' a fan supplied from a 6amp lighting circuit. There are squillions of them installed like that, everywhere, many of them by me.

 

[westward10]

I think that the makers put an FCU (with a 3amp fuse) in their diagrams to cater for where the fan is powered from a ring final and the fan and the connecting wiring need to be protected from a fault current limited only by a 32amp MCB.

IMO there is no need to 'fuse down' a fan supplied from a 6amp lighting circuit. There are squillions of them installed like that, everywhere, many of them by me.

Totally agree.

 

[telectrix]

it's all a matter of discrimination ( or the lack of ). some time ago, i had a vivarium lamp blow. it took out 2 x 5A plug top fuses and the 16A MCB in the CU.

 

[haptism]

Thanks for responses, its going onto existing lighting circuit and will have a 3 pole isolator; I think it would be safe on a 6a rcd'd lighting circuit, however would like to fit it and have no questions from customer if he reads the instructions. Will check out those recommendations !, thanks

 

[mydigitalhome]

Some non timed fans ask for 1A fuse, manufacturers requirement takes president so if you installed incorrectly, customer could insist you carry out a costly upgrade to comply at your cost. If you don't tell client you are leaving yourself legally exposed. Is it worth risking your business for a fan?

 

[westward10]

Some non timed fans ask for 1A fuse, manufacturers requirement takes president so if you installed incorrectly, customer could insist you carry out a costly upgrade to comply at your cost. If you don't tell client you are leaving yourself legally exposed. Is it worth risking your business for a fan?

This is true but what are the chances.

 

[Midwest]

If he uses a fused TP&N isolator, he's just has to put in a suitably sized fuse

 

[unconditional]

If it's keeping you awake I'd pop an inline fuseholder inside the fan itself, can't say I'd ever bother myself as like said it's debatable a 3A 1361 fuse would beat a B6 MCB anyway.

Or you could do like barratt homes and stick a sw/f/sp marked "fan" that in fact controls the whole bathroom lights & all and completely miss the whole point of having a fan isolator and causes the likes of me to spend an hour trying to trace a break in a circuit before realising what amateur fwits I'm following around.

 

[westward10]

If it's keeping you awake I'd pop an inline fuseholder inside the fan itself, can't say I'd ever bother myself as like said it's debatable a 3A 1361 fuse would beat a B6 MCB anyway.

Or you could do like barratt homes and stick a sw/f/sp marked "fan" that in fact controls the whole bathroom lights & all and completely miss the whole point of having a fan isolator and causes the likes of me to spend an hour trying to trace a break in a circuit before realising what amateur fwits I'm following around.

The point of the fuse is to provide overcurrent protection not fault protection.

 

[westward10]

If he uses a fused TP&N isolator, he's just has to put in a suitably sized fuse

Which pole of the TP isolator does the fuse protect, switch live or permanent live.

 

[haptism]

Maybe im being a bit OTT but if i could find a fan, which does not need an overrun btw, that does not request to be fused, then I will be more happy than usual.

 

[Leesparkykent]

you can wire it in a way that the fuse is in line with the perm and switched live of the fan by using a double pole light switch. Excel 3 Pole Fused Fan Isolator Switch - White | QVS Electrical Wholesalers - http://www.qvsdirect.com/excel-3-pole-fused-fan-isolator-switch-white

 

[haptism]

. Excel 3 Pole Fused Fan Isolator Switch - White | QVS Electrical Wholesalers - http://www.qvsdirect.com/excel-3-pole-fused-fan-isolator-switch-white

Aha, I was just looking for that after trawling through fan specs, most helpful, thanks very much.

 

[westward10]

you can wire it in a way that the fuse is in line with the perm and switched live of the fan by using a double pole light switch. Excel 3 Pole Fused Fan Isolator Switch - White | QVS Electrical Wholesalers - http://www.qvsdirect.com/excel-3-pole-fused-fan-isolator-switch-white

Sounds a right performance.

 

[Leesparkykent]

Aha, I was just looking for that after trawling through fan specs, most helpful, thanks very much.

no probs mate

 

[haptism]

Got there in the end !

 

[Leesparkykent]

Sounds a right performance.

no not really if your chucking the cables in on a 1st fix.

 

[Deleted member 9648]

This came about because some years back a fan caused a fire, and because the contractor had not installed a 3a fuse as per manufacturers instruction he was prosecuted for causing the fire. Nobody stated the bleeding obvious that a 3a fuse would not have made a scrap of difference. This led the NICEIC to advise their contractors to fit the fuse...and to code non fused fans. Bull**** but there you go.

 

[haptism]

Ive been out the loop for10ish years and slowly getting back into it all again because it gives me something to focus on; the non fused fan isolators were familiar, never seen these fused ones until now;

 

[westward10]

I don't get these fused triple-pole switches, they only fuse one of the poles so what is the point. May as well use a standard triple-pole switch with a two gang grid with two fuses fitted. Am I misreading this.

 

[Wilko]

Ive been out the loop for10ish years and slowly getting back into it all again because it gives me something to focus on; the non fused fan isolators were familiar, never seen these fused ones until now;

Hi H, you are not alone. Lee's 3 pole fused isolator is one of the many neat things I have learnt here. Cheers

 

[Wilko]

I don't get these fused triple-pole switches, they only fuse one of the poles so what is the point. May as well use a standard triple-pole switch with a two gang grid with two fuses fitted. Am I misreading this.

With Tin Hat On, I'm hoping I've got it : the unit has a separate fuse to the 3 pole switch so we can fuse the incoming L and then split it into L for the fan (via 3pole) and send L off to the other half of the new DP light sw, when it comes back it goes into as SL (via the 3pole). Clear as mud ?

 

[Leesparkykent]

I don't get these fused triple-pole switches, they only fuse one of the poles so what is the point. May as well use a standard triple-pole switch with a two gang grid with two fuses fitted. Am I misreading this.

could do but will look rubbish.

 

[Leesparkykent]

With Tin Hat On, I'm hoping I've got it : the unit has a separate fuse to the 3 pole switch so we can fuse the incoming L and then split it into L for the fan (via 3pole) and send L off to the other half of the new DP light sw, when it comes back it goes into as SL (via the 3pole). Clear as mud ?

Spot on

 

[westward10]

Am I correct that it does in fact fuse only one pole, sorry if I am being dumb but I really don't get it.

 

[haptism]

All cartridge fuse only one pole for overload, just like an inline fuse ?!

edit missed the last posts, but still I would guess it only fused the one pole for overload

 

[Wilko]

All cartridge fuse only one pole for overload, just like an inline fuse ?!

edit missed the last posts, but still I would guess it only fused the one pole for overload

Both L and SL for fan can be fused, but it needs another pole on the light sw and cabling.

 

[westward10]

Both L and SL for fan can be fused, but it needs another pole on the light sw and cabling.

Does the switch come with instructions for this because it would be easy to get it wrong.

 

[Leesparkykent]

Does the switch come with instructions for this because it would be easy to get it wrong.

No because there is a few ways to achieve the same outcome.

 

[Richard Burns]

Presumably the option is there to wire it as you require however I would expect that most people might wire it like this:

As this covers the most obvious arrangement that is identified on most fan installation instructions (assuming the TP isolator has a 3mm contact gap)

 

[westward10]

No because there is a few ways to achieve the same outcome.

Must admit I have never seen these switches. They seem to be a solution for a problem which isn't really there and only solves the so called problem by 50% leaving the installer to put in place the rest of the solution. This really should be made clear by the manufacturer.

 

[mydigitalhome]

I normally wire FSO with 3A fuse and bring the complete bathroom lights down to 3A then next to that 3pole fan isolator for fan over run and all legal easy on new build less fun on existing but not impossible.

 

[HandySparks]

Must admit I have never seen these switches. They seem to be a solution for a problem which isn't really there and only solves the so called problem by 50% leaving the installer to put in place the rest of the solution. This really should be made clear by the manufacturer.

Why do they only solve half the problem? Generally I use the circuit shown by Richard Burns (above), so the line supply to the bathroom lighting and fan goes via a 3A fuse before any switches. Whether you use a single plate solution or two separate accessories makes no difference.

 

[westward10]

Why do they only solve half the problem? Generally I use the circuit shown by Richard Burns (above), so the line supply to the bathroom lighting and fan goes via a 3A fuse before any switches. Whether you use a single plate solution or two separate accessories makes no difference.

I agree but do the manufacturer make that clear. Be interesting to undertake a study, take 10 sparks, give them the necessary parts and cable and see how many come up with the correct circuit.

 

[Toneyz]

Correct me if I'm wrong the 3A fuse is as posted for overload protection the 3 pole switch for isolation. I think the fan is powered via live/line and neutral therfore fuse in perm.live the switch wire just triggers the timer and not powering the fan motor.

 

[Richard Burns]

Correct me if I'm wrong the 3A fuse is as posted for overload protection the 3 pole switch for isolation. I think the fan is powered via live/line and neutral therefore fuse in perm.live the switch wire just triggers the timer and not powering the fan motor.

The fuse is not required to protect the switched line from overload, however if the fuse blows and the fan stops and then someone is working on the fan they will be expecting that the fuse has removed power from the fan however the switched line would still be live and subject someone to the risk of shock.
Whilst you might say anyone with any sense will switch off the isolator, since these are domestic fans non professional persons are likely to be investigating and therefore may be subject to a shock risk.

 

[Midwest]

Which pole of the TP isolator does the fuse protect, switch live or permanent live.

Its your choice

 

[Midwest]

The fuse is not required to protect the switched line from overload, however if the fuse blows and the fan stops and then someone is working on the fan they will be expecting that the fuse has removed power from the fan however the switched line would still be live and subject someone to the risk of shock.
Whilst you might say anyone with any sense will switch off the isolator, since these are domestic fans non professional persons are likely to be investigating and therefore may be subject to a shock risk.

I think you are thinking this too much

 

[Deleted member 26818]

Presumably the option is there to wire it as you require however I would expect that most people might wire it like this:

View attachment 34115

As this covers the most obvious arrangement that is identified on most fan installation instructions (assuming the TP isolator has a 3mm contact gap)

Looks like it is wired back to front.
Feed to the light switch should be taken from the unfused side of the fuse.

 

[Richard Burns]

Looks like it is wired back to front.
Feed to the light switch should be taken from the unfused side of the fuse.

That is really rather the whole point, to ensure the whole of the fan is fused down, not just one half of the supply.

 

[Deleted member 26818]

Yes, just don't like the light being fused with the fan.

 

[westward10]

Looks like it is wired back to front.
Feed to the light switch should be taken from the unfused side of the fuse.

Like I said before the switch is a half baked idea to solve a problem which isn't a problem in the first place.

 

[Midwest]

The same could said of the hallway & landing light switch. Should we not be wiring the ground floor & first floor lighting from the same mcb. If we use a non fused TP&N isolator, if a fan malfunctions, the same non professional person, could put his pinkies in there and get a shock. There's just no helping some people.

The use of a fused TP&N switch, in it's simplest form, allows the installer to 'take account of the manufactures instructions', by fusing the live supply to a fan. If that's what you want to do.

 

[westward10]

Agreed but it has been manufactured to fuse only one pole leaving the installer to figure out the rest. I guarantee these isolators have been fitted the conventional way leaving only one pole fused there is absolutely no doubt about it.

 

[Deleted member 9648]

Agreed but it has been manufactured to fuse only one pole leaving the installer to figure out the rest. I guarantee these isolators have been fitted the conventional way leaving only one pole fused there is absolutely no doubt about it.

My understanding is the 3a fuse is (laughably) intended to prevent the fan catching fire in the event of the motor seizing. As a timed fan will not operate without the permanent live it would seem to me that only fusing this pole and not the switched live would still achieve that (comical) aim.
Maybe the next amendment will require all fans to be constructed of non combustible material....ie sheet steel. Or the installer must construct a non combustible enclosure around the entire bathroom.

 

[westward10]

My understanding is the 3a fuse is (laughably) intended to prevent the fan catching fire in the event of the motor seizing. As a timed fan will not operate without the permanent live it would seem to me that only fusing this pole and not the switched live would still achieve that (comical) aim.
Maybe the next amendment will require all fans to be constructed of non combustible material....ie sheet steel. Or the installer must construct a non combustible enclosure around the entire bathroom.

There would be an argument the switched live will still be live if the fuse blows, not from me but I must agree with the 3A fuse being used to prevent fire, would it really blow if the fan locked before the windings heated the enclosure enough to catch fire. I thought these fans incorporated thermal fuses anyway.