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

 

[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.