I'm sorely tempted not to bother fitting a 3A fuse to my bathroom
extractor fan. I don't see the point!

T

wrote in message
...
I'm sorely tempted not to bother fitting a 3A fuse to my bathroom
extractor fan. I don't see the point!

T

Who says you need to?

Adam

On 28 Apr, 17:01, "ARWadsworth"
wrote:
wrote in message

...

I'm sorely tempted not to bother fitting a 3A fuse to my bathroom
extractor fan. I don't see the point!

T

Who says you need to?

Adam

I sense a leading question - the manufacturer.

T

wrote in message
...
On 28 Apr, 17:01, "ARWadsworth"
wrote:
wrote in message

...

I'm sorely tempted not to bother fitting a 3A fuse to my bathroom
extractor fan. I don't see the point!

T

Who says you need to?

Adam

I sense a leading question - the manufacturer.

T

I have seen some manufaturers that say that.

Which one is it this time?

Adam

On 28 Apr, 17:17, "ARWadsworth"
wrote:
wrote in message

...



On 28 Apr, 17:01, "ARWadsworth"
wrote:
wrote in message

...

I'm sorely tempted not to bother fitting a 3A fuse to my bathroom
extractor fan. I don't see the point!

T

Who says you need to?

Adam

I sense a leading question - the manufacturer.

T

I have seen some manufaturers that say that.

Which one is it this time?

Adam

Actually it's all of the ones I've looked at - though Xpelair do
specify a 5A fuse. Which manufacturers don't specify a fuse, as I'll
get one of those...

T

wrote in message
...
On 28 Apr, 17:17, "ARWadsworth"
wrote:
wrote in message

...



On 28 Apr, 17:01, "ARWadsworth"
wrote:
wrote in message

...

I'm sorely tempted not to bother fitting a 3A fuse to my bathroom
extractor fan. I don't see the point!

T

Who says you need to?

Adam

I sense a leading question - the manufacturer.

T

I have seen some manufaturers that say that.

Which one is it this time?

Adam

Actually it's all of the ones I've looked at - though Xpelair do
specify a 5A fuse. Which manufacturers don't specify a fuse, as I'll
get one of those...

T

I would want to if it was fed from the ring main.

If fed from the lighting circuit then I would be reluctant.

On 28 Apr, 17:34, "John" wrote:
wrote in message

...



On 28 Apr, 17:17, "ARWadsworth"
wrote:
wrote in message

...

On 28 Apr, 17:01, "ARWadsworth"
wrote:
wrote in message

...

I'm sorely tempted not to bother fitting a 3A fuse to my bathroom
extractor fan. I don't see the point!

T

Who says you need to?

Adam

I sense a leading question - the manufacturer.

T

I have seen some manufaturers that say that.

Which one is it this time?

Adam

Actually it's all of the ones I've looked at - though Xpelair do
specify a 5A fuse. Which manufacturers don't specify a fuse, as I'll
get one of those...

T

I would want to if it was fed from the ring main.

If fed from the lighting circuit then I would be reluctant.

My bathrooms have their own circuits - from 6A RCBOs.

T

On Apr 28, 5:34 pm, "John" wrote:
wrote in message

...



On 28 Apr, 17:17, "ARWadsworth"
wrote:
wrote in message

...

On 28 Apr, 17:01, "ARWadsworth"
wrote:
wrote in message

...

I'm sorely tempted not to bother fitting a 3A fuse to my bathroom
extractor fan. I don't see the point!

T

Who says you need to?

Adam

I sense a leading question - the manufacturer.

T

I have seen some manufaturers that say that.

Which one is it this time?

Adam

Actually it's all of the ones I've looked at - though Xpelair do
specify a 5A fuse. Which manufacturers don't specify a fuse, as I'll
get one of those...

T

I would want to if it was fed from the ring main.

If fed from the lighting circuit then I would be reluctant.

SO if something goes wrong with it, it takes out all the light as
well. That's useful.

"Man at B&Q" wrote in message
...
On Apr 28, 5:34 pm, "John" wrote:
wrote in message

...



On 28 Apr, 17:17, "ARWadsworth"
wrote:
wrote in message

...

On 28 Apr, 17:01, "ARWadsworth"
wrote:
wrote in message

...

I'm sorely tempted not to bother fitting a 3A fuse to my bathroom
extractor fan. I don't see the point!

T

Who says you need to?

Adam

I sense a leading question - the manufacturer.

T

I have seen some manufaturers that say that.

Which one is it this time?

Adam

Actually it's all of the ones I've looked at - though Xpelair do
specify a 5A fuse. Which manufacturers don't specify a fuse, as I'll
get one of those...

T

I would want to if it was fed from the ring main.

If fed from the lighting circuit then I would be reluctant.

SO if something goes wrong with it, it takes out all the light as
well. That's useful.

Hmm - if there was a fault, it would probably take both out. So I would
advocate the one 6amp breaker, or a much lower ampage fuse. Even then a
standard cartridge fuse would blow and a fast MCB would also go at the same
time!

On Apr 28, 5:48 pm, "Fredxx" wrote:
"Man at B&Q" wrote in ...



On Apr 28, 5:34 pm, "John" wrote:
wrote in message

...

On 28 Apr, 17:17, "ARWadsworth"
wrote:
wrote in message

...

On 28 Apr, 17:01, "ARWadsworth"
wrote:
wrote in message

...

I'm sorely tempted not to bother fitting a 3A fuse to my bathroom
extractor fan. I don't see the point!

T

Who says you need to?

Adam

I sense a leading question - the manufacturer.

T

I have seen some manufaturers that say that.

Which one is it this time?

Adam

Actually it's all of the ones I've looked at - though Xpelair do
specify a 5A fuse. Which manufacturers don't specify a fuse, as I'll
get one of those...

T

I would want to if it was fed from the ring main.

If fed from the lighting circuit then I would be reluctant.

SO if something goes wrong with it, it takes out all the light as
well. That's useful.

Hmm - if there was a fault, it would probably take both out.

Maybe not if it was individually fused.

On 28 Apr, 17:48, "Fredxx" wrote:
"Man at B&Q" wrote in ...



On Apr 28, 5:34 pm, "John" wrote:
wrote in message

....

On 28 Apr, 17:17, "ARWadsworth"
wrote:
wrote in message

...

On 28 Apr, 17:01, "ARWadsworth"
wrote:
wrote in message

...

I'm sorely tempted not to bother fitting a 3A fuse to my bathroom
extractor fan. I don't see the point!

T

Who says you need to?

Adam

I sense a leading question - the manufacturer.

T

I have seen some manufaturers that say that.

Which one is it this time?

Adam

Actually it's all of the ones I've looked at - though Xpelair do
specify a 5A fuse. Which manufacturers don't specify a fuse, as I'll
get one of those...

T

I would want to if it was fed from the ring main.

If fed from the lighting circuit then I would be reluctant.

SO if something goes wrong with it, it takes out all the light as
well. That's useful.

Hmm - if there was a fault, it would probably take both out. *So I would
advocate the one 6amp breaker, or a much lower ampage fuse. *Even then a
standard cartridge fuse would blow and a fast MCB would also go at the same
time!

Well yes, if "something" goes wrong with the fan then it could trip
all the bathroom lights and vice versa. However, some manufacturers
recommend the fuse be placed upstream of any connection to a light (so
that both switched and permanent live are fused), which has a similar
effect.

I would prefer to isolate the fan and switch the RCBO back on, than
hunt around for a spare 3A fuse!

T

On Apr 28, 7:23*pm, "ARWadsworth"
wrote:
A 6A B type RCBO will probably trip before a 3A BS1362 fuse.

Indeed, generally 5*In for Type B and 7-10*In for BS1362.

I'm always wary of cited fire statistics, too much grouping occurs
along with an underlying "default cause". Those fire stats are perhaps
masking what *kind* of extractor re risks.

I suspect many are in fact cooker hood extractor fires caused by
clogged or missing grease filters, flexi-pvc, clogged outlet
flyscreen, jammed backdraught shutter or jammed/interlocked louvre
shutter. There is less probability of a conventional bathroom/kitchen
window/wall extractor causing a fire - but certainly not zero
probability.

The problem common to most is the use of AC fans where AC motors
firstly require quite significant cooling (or overheating results) and
secondly current draw peaks at fully stalled condition (causing
thermal runaway). To prevent overheating the normal cutout is a
bimetallic strip, however this can fail, be omitted or simply
inadequately tailored to the fan assembly. The fan assembly needs to
be designed so as not to catch fire or melt in such a situation,
historically AC fans used to use metal rotors, metal struts & metal
housings to dissipate the thermal energy of a stalled fan (as well as
bimetallic thermal cutout).

DC fans should have replaced AC long ago in many domestic
applications, what is outrageous is the prices charged because for the
most part the fan is cheaper and lasts longer due to lower thermal
loading - the cost is a simply PSU. No doubt DC extractors will then
suffer power supply fires or exploding capacitors or such like.

Cooker hoods are indeed quite notorious for fires where neglected, I'm
not sure they incorporate glass-bulb thermal fuses as a backup cutout.

ARWadsworth wrote:

A 6A B type RCBO will probably trip before a 3A BS1362 fuse.


Maybe on a short circuit or an earth fault. A 3A fuse is going to blow
before a 6A breaker on a long-term moderate over-current - which clearly
is the likely fire-causing scenario in this case.

Dave Osborne wrote:

Well you *absolutely* should fit a fuse.

A number of house fires have attributed to extractor fans catching fire.

A work colleague of mine suffered exactly this.

Pete

On 29 Apr, 01:12, Pete Verdon
d wrote:
Dave Osborne wrote:
Well you *absolutely* should fit a fuse.

A number of house fires have attributed to extractor fans catching fire.

A work colleague of mine suffered exactly this.

Pete

If they need a fuse, why don't they come with one?

T

wrote in message
...
On 28 Apr, 17:17, "ARWadsworth"
wrote:
wrote in message

...



On 28 Apr, 17:01, "ARWadsworth"
wrote:
wrote in message

...

I'm sorely tempted not to bother fitting a 3A fuse to my bathroom
extractor fan. I don't see the point!

T

Who says you need to?

Adam

I sense a leading question - the manufacturer.

T

I have seen some manufaturers that say that.

Which one is it this time?

Adam

Actually it's all of the ones I've looked at - though Xpelair do
specify a 5A fuse. Which manufacturers don't specify a fuse, as I'll
get one of those...

T
I fitted a vent axia this morning. The circuit diagrams showed a fuse apart
from where the fan cam one with the light.

Ada.

On 29 Apr, 00:43, Dave Osborne wrote:
ARWadsworth wrote:
A 6A B type RCBO will probably trip before a 3A BS1362 fuse.

Maybe on a short circuit or an earth fault. A 3A fuse is going to blow
before a 6A breaker on a long-term moderate over-current - which clearly
is the likely fire-causing scenario in this case.

OK, I give in! I'll fit the fuse, and the isolator.

There is a part of me however, that thinks that if a fuse is so
important, then why didn't the manufacturer fit one in the fan in the
first place?

So the wiring goes like this:

Feed from CU -------- fused spur -------- junction box -------------
isolator -------- fan

-------------lights

-------------switch

T

On 29 Apr, 00:43, Dave Osborne wrote:
ARWadsworth wrote:
A 6A B type RCBO will probably trip before a 3A BS1362 fuse.

Maybe on a short circuit or an earth fault. A 3A fuse is going to blow
before a 6A breaker on a long-term moderate over-current - which clearly
is the likely fire-causing scenario in this case.

OK, I'll fit a fuse, and an isolator.

If a fuse is so critical, why isn't it built into the fan?

T

wrote:
On 29 Apr, 00:43, Dave Osborne wrote:
ARWadsworth wrote:
A 6A B type RCBO will probably trip before a 3A BS1362 fuse.
Maybe on a short circuit or an earth fault. A 3A fuse is going to blow
before a 6A breaker on a long-term moderate over-current - which clearly
is the likely fire-causing scenario in this case.

OK, I'll fit a fuse, and an isolator.

If a fuse is so critical, why isn't it built into the fan?

T

You could ask the same question about immersion heaters or electric
kettles or vacuum cleaners or central heating boilers - some have a
fuse in the FCU and others have a fuse in the plug top.

The answer is that the fuse is a standard type, is located in a standard
place with a straightforward method of access and it's therefore easy to
check that the right fuse is fitted and easy to change a fuse without
dismantling the appliance.

HTH

wrote in message
...
On 29 Apr, 00:43, Dave Osborne wrote:
ARWadsworth wrote:
A 6A B type RCBO will probably trip before a 3A BS1362 fuse.

Maybe on a short circuit or an earth fault. A 3A fuse is going to blow
before a 6A breaker on a long-term moderate over-current - which clearly
is the likely fire-causing scenario in this case.

OK, I'll fit a fuse, and an isolator.

If a fuse is so critical, why isn't it built into the fan?

T

Greenwood Airvac state in their installation instuctions "when supplied from
a 5 amp lighting circuit no local fuse is needed" And that does include 6A
MCBs

Adam

Dave Osborne wrote:

A number of house fires have attributed to extractor fans catching fire.
The manufacturer does not want to tell you this, so they conveniently
forget to mention *why* they recommend a 3A fused spur.

Hmmm, news to me!

However my bathroom extractor fan failed a few years ago. When I took
it apart there clearly had been a little fire. I chased the supliers
for a while as I considered this serious and felt it warranted some
attention. But I was stone-walled and ignored at every stage. I assumed
my case was a one off and so I let it slip.

I am rather preeved now, to discover this is rather common.

I suspect that it was not the fan that caught fire but the timer
circuit that controls the fans run on. Every one of these I have looked
at has a badly discoloured PCB showing signs of major overheating.

These circuits are *ALL* OBVIOUSLY badly designed... which seems odd.