Fusing Fans to manufacturers spec

[nickblake]

Well chaps ive been looking at the manufacturer requirements for fusing down fans ,an every one appears to require only the permernant live to be fused so having words with those nice people at scolmore click you can do it easily with the grid range that doesnt actually look like grid fuse and an isolator in the same switch brilliant thats what i say good old Click scholmore

 

[telectrix]

looks tidy.

 

[Strima]

Like that, saves messing around wiring in two different items.

 

[Octopus]

How much?

 

[telectrix]

probably less than a separate isol. and FCU when you factor in 2 back boxes, never mind the extra cutting out and time running cable.

 

[Octopus]

probably less than a separate isol. and FCU when you factor in 2 back boxes, never mind the extra cutting out and time running cable.

Quite agree, still like to know!

 

[Amp David]

How much?

I get those isolators for about 2 quid, the faceplate for about 90p and a fused unit is around 1.50.

Never thought of doing that and been using the Click mini grid for a while now.

Nice one

 

[Dcf]

The click stuff is one of the best thought out at the moment.
i like their grid stuff as well.even on normal plates you can swap a 2way for an intermediate easily.

 

[Octopus]

I get those isolators for about 2 quid, the faceplate for about 90p and a fused unit is around 1.50.

Never thought of doing that and been using the Click mini grid for a while now.

Nice one

This may sound a silly question but how to you wire it if you're using a fan with an over run timer?

 

[telectrix]

as i see it, it's a 3 pole isolator with a fuse in the permanent L.

 

[Amp David]

This may sound a silly question but how to you wire it if you're using a fan with an over run timer?

Perm feed through fuse, into isolator then out to fan. Neutral and switched into the out of isolator.

 

[nickblake]

This may sound a silly question but how to you wire it if you're using a fan with an over run timer?

According to the manufacturers instructions i have read you only need to fuse down the permernant feed and not the switch feed , so ideal in my mind ill let you know the cost

 

[topquark]

According to the manufacturers instructions i have read you only need to fuse down the permernant feed and not the switch feed , so ideal in my mind ill let you know the cost

Yep, perm live only on the ones I've seen. I've also noticed that the rule about fusing it only applies to the UK! Anyone know why we're blessed with that requirement here and no one else is?

 

[kingeri]

It is a bit strange, as the whole circuit is protected at 6a. That isolator with integrated fuse on the perm live is a simple but great idea, as said saves the hassle of having to use two accessories. Why does the perm live need fusing down but not the switched live?

 

[topquark]

It is a bit strange, as the whole circuit is protected at 6a. That isolator with integrated fuse on the perm live is a simple but great idea, as said saves the hassle of having to use two accessories. Why does the perm live need fusing down but not the switched live?

They're both fused because of the way it's suggested to be fed (via the perm live). If no other countries need to add protection, then why do we? I don't believe other countries lighting is 3A to start with. I wonder if it's a misunderstanding that has been propogated across the chinese manuf plants.

 

[Strima]

Not enough 3A fuses were being sold, its a conspiracy I tell ya!!!

If they insist on 3A protection why not just provide them with one installed? Or am I thinking too much?

 

[topquark]

Not enough 3A fuses were being sold, its a conspiracy I tell ya!!!

If they insist on 3A protection why not just provide them with one installed? Or am I thinking too much?

That's the point mate, they don't ask any other country to add a fuse (so it must be OK without that protection?).

 

[telectrix]

so why don't we all bombard manrose and the like with emails asking why?

 

[Richard Burns]

Not enough 3A fuses were being sold, its a conspiracy I tell ya!!!

If they insist on 3A protection why not just provide them with one installed? Or am I thinking too much?

If you installed a fuse in the fan then only one of the SL or L would be fused, if you installed two fuses one in each Line then one fuse could go and still leave a live circuit on the fan. You want the fuse before the isolator. As per post #1

 

[telectrix]

but the whole point of the post is that the manufacturers instructions only call for the permanent L to be fused.......is that a mistake on their part?

 

[Richard Burns]

No the instructions ask for the permanent line to be fused before the split to permanent and switched so not at the fan.

 

[Strima]

I can see both sides for the fusing of both lines. Was the fuse brought in due to motors burning out and causing fires? If that's the case then only the perm L needs fusing as the SL is only a signal to the PCB as any fault should cause overload on the perm L. Or is my logic way out? Ideally what is needed is a three pole fused switch.

 

[Richard Burns]

Engage brain and read thread before posting!! I see what you say about the permanent line fusing I hadn't actually thought about the arrangement above and now realise it is only fusing one part of the circuit and not the whole lot.
Sorry.

 

[topquark]

Like so:

 

[telectrix]

o bugger. just open the bloody window and fart.

 

[nickblake]

I can see both sides for the fusing of both lines. Was the fuse brought in due to motors burning out and causing fires? If that's the case then only the perm L needs fusing as the SL is only a signal to the PCB as any fault should cause overload on the perm L. Or is my logic way out? Ideally what is needed is a three pole fused switch.

Exactly the reason , there were a spate of fire including one hotel in london where some people died as a resault the electrician was prossecuted and if im not mistaken charged with unlawfull killing due to the fact that he had not followed manufacturers instructions

 

[Octopus]

What I've noticed is that on the last 2 fans I've installed not only do they both call for 3A fuses but they also state that "isolation" is also required - so even if the doubters here say they aren't going to bother with 3A fuses will they bother with isolators too?

 

[Strima]

Always stick an isolator in when doing a new fan, makes it easier for testing and working on and fans annoy me when I go for a gush at three in the morning and it wants to runs on for twenty minutes hence I give the customer the option of where they want it... :lol:

 

[nickblake]

Always stick an isolator in when doing a new fan, makes it easier for testing and working on and fans annoy me when I go for a gush at three in the morning and it wants to runs on for twenty minutes hence I give the customer the option of where they want it... :lol:

i have 2 fan isolators to install i will now be using the click fuse with isolators for those intrested in the isolators in the pick order codes for the parts are MD020WH fan isolator MD220WH locable version MD047PW fuse module and PRW403 for the face plate these also come in a full range silver brass chrome etc blimby i sound like an advert lol

 

[Strima]

They do look nice and will bear them in mind.

 

[somersetsparks]

I believe only the permanent live needs fusing as the switch live just 'switches' the actual fan motor only ever runs off of the permanent live. They don't really care about the fuse blowing and leaving a permanent feed at the fan.
Saying that though, I have yet to see a fused fan in a house.

 

[nickblake]

I believe only the permanent live needs fusing as the switch live just 'switches' the actual fan motor only ever runs off of the permanent live. They don't really care about the fuse blowing and leaving a permanent feed at the fan.
Saying that though, I have yet to see a fused fan in a house.

suprising isnt it i always put them in well since ive worked for myself

 

[somersetsparks]

Indeed, even stranger that they only have to have them in the uk, I think it may be a misinterpretation by the manufacturers somewhere along the line, lazy b*ggers should just put a little 1361 carrier in the fan itself !

 

[Doomed]

I believe only the permanent live needs fusing as the switch live just 'switches' the actual fan motor only ever runs off of the permanent live. They don't really care about the fuse blowing and leaving a permanent feed at the fan.
Saying that though, I have yet to see a fused fan in a house.

Come and look at some of the houses in Dorset then.

 

[somersetsparks]

Come and look at some of the houses in Dorset then.

Might well do, not to far from somerset, see thing is there a bit posher over your way!

 

[Guest111]

Looking at fig 4 on that drawing it appears to be based on a seperate switch for the fan as you have L and N coming in with a fuse in the live then it splits and a perm live goes to fan and one goes through the switch,obviously someone has very little knowledge of how fans are wired over here i.e switched with light.typical manufacturer type of thing really .

 

[kingeri]

Sorry to re-open this one, but just wanted to confirm something. I've always believed that when the instructions state that only the perm line needs fusing at 3amps, then this means at the fan, hence the switched line is not fused. To fuse it to encompass both with one fuse would surely mean fusing the bathroom lights at 3amps as well. Seeing as the click accessory has only one fuse, I take it I am correct in assuming that perm live is referring only to the actual perm live feed to the fan? Sorry to be a bore.

 

[Deleted member 19807]

could someone let me know which makes of timed fan only require the perm Line to be fused as all the ones i fit are the same as in post 24 that shows both perm and switched needing fusing. Would be nice to not have to put the light on the fuse as well.

 

[yellowvanman]

could someone let me know which makes of timed fan only require the perm Line to be fused as all the ones i fit are the same as in post 24 that shows both perm and switched needing fusing. Would be nice to not have to put the light on the fuse as well.

Try making the fan work with just the switched live and neutral!

I assume the perm line actually feeds the motor etc. and makes the switched live useless if not present.

 

[Deleted member 19807]

Try making the fan work with just the switched live and neutral!

I assume the perm line actually feeds the motor etc. and makes the switched live useless if not present.

that won't work with a timed fan, you need both perm and switched.

 

[cbw]

Too many ciders again!

 

[sjm]

If you fit Vortice or Solar & Pallau fans the manufacturers instuctions only require a "multipole switch for isolation" so makes the whole fusing down argument redundant.

All manufacturers instructions I've seen require the fuse to be in the line BEFORE the split for the switched live.
So IMHO although the original post looks good I don't think it would hold water in a court of law IF anything went wrong, and surely thats the reason we bend over backwards to follow nonsensical regs and manufacturers instructions.

 

[Deleted member 19807]

Too many ciders again!

not yet but i'm working on it

 

[kingeri]

If you fit Vortice or Solar & Pallau fans the manufacturers instuctions only require a "multipole switch for isolation" so makes the whole fusing down argument redundant.

All manufacturers instructions I've seen require the fuse to be in the line BEFORE the split for the switched live.
So IMHO although the original post looks good I don't think it would hold water in a court of law IF anything went wrong, and surely thats the reason we bend over backwards to follow nonsensical regs and manufacturers instructions.

I've seen plenty of one-sheet poor-English instructions that state only something like 'Permanent Line must be fused down at 3amps'.

 

[kingeri]

To be safe I think I'll start fusing the whole bathroom lighting at 3a then no-one can send me to jail for anything...

 

[Strima]

To be safe I think I'll start fusing the whole bathroom lighting at 3a then no-one can send me to jail for anything...

That's the easiest option. With the vast majority made in China and with **** poor installation instructions it's hard at times to work out what they want.

 

[Lucas]

I must be the only person that doesn't put it through a switch fuse. Might be manufactors instructions but I don't see the point

 

[Octopus]

I must be the only person that doesn't put it through a switch fuse. Might be manufactors instructions but I don't see the point

Just don't show a fan installation at your next assessment,

Are you one of those who doesn't bother with cooker isolation, or shower isolation either?

 

[tank]

To be safe I think I'll start fusing the whole bathroom lighting at 3a then no-one can send me to jail for anything...

isn't that what we'd be doing by wiring as per fig 4 post 24? do people really wire fans this way? when the fan is isolated, so is the feed to the light? isolator and fuse after the ceiling rose, surely

 

[Richard Burns]

Whilst I agree that the fuse is fairly pointless since the circuit is protected by a 6A breaker (fires notwithstanding) since most manufacturers state the fuse should be before the light this is what I would tend to do.

If you only fuse the permanent line going to the fan then if the fuse goes you can still supply a line to the fan (that may now be in a dangerous state if it has overheated or such) by switching on the light. I do not know if the SL is just an electronic run signal to employ the PL or if the two lines are commoned up in the fan, but if it is the latter then you could be trying to operate the fan once it has blown the fuse and presumably cause the fire that was averted by the fuse blowing, or trip the 6A lighting if it is a more direct fault. If the former then there can still be a line supplied to a damaged circuit board which cannot be good.

e.g. with just PL fused: switch on bathroom light, fan starts, switch off bathroom light, fan overrun continues, you leave, five minutes later fuse goes, later you come back, switch on bathroom light, fan bursts into flames or all the lights go out.

With supply fused: switch on bathroom light, fan starts, switch off bathroom light, fan overrun continues, you leave, five minutes later fuse goes, later you come back, switch on bathroom light, no light, oh dear something has gone wrong, better find out what it is.

I think the two options are as shown in this borrowed and modified diagram and I would definitely prefer my fuses to isolate the whole supply and not just one leg of it.

Good

Bad
(in my opinion)