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Topic Title: Bathroom lighting at 3A
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Created On: 02 February 2012 10:21 PM
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 05 February 2012 03:21 PM
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weirdbeard

Posts: 3116
Joined: 26 September 2011

Hi DR, good shout, seems they have built in thermal overload protection, maybe the makers who specify an external fuse are ones most likely to catch fire!

http://www.justfans.co.uk/catalogues/silent.pdf

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 24 February 2012 11:41 AM
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urdirectUK

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Joined: 22 February 2012

Good post. This is a very nice blog that I will definitively come back to more times this year! Thanks for informative post.
 01 February 2016 03:09 PM
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jgjhome

Posts: 1
Joined: 25 July 2008

I recently purchased a new Vent Axia fan VASF 100T, and only discovered thet 3 amp protection was required when i read the leaflet.

Why dont they fit an in line fuse like you have in an intruder alarm panel. 95% of the project I work on have 3 pole fan isolators wired on the lighting circuit which is usually 6 amp. Or make the wiring capable of 6 amp protection.

I agree with the earlier comments 3 pole fan switches are installed for run on timers, the timers are PCB's therefore the 3 poles switch should have 2no fuses, 1no for Line and 1no for switched.

Of course now bathrooms have to have rcbo and LED lights are popular may 3 amp RCB will become the norm. But its a cost and inconvienant problem to discover once you have ordered it, The manufacturers should be making it obvious as its not fit for purspose as a replacement fan, because it involves changing the wiring.
 01 February 2016 04:13 PM
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TimJWatts

Posts: 421
Joined: 07 August 2013

Originally posted by: DR2366

S&P fans I think don't specify a 3A fuse.


I have a vague feeling mine does (in line axial S&P).

I thought it was a bit silly, but will do so as it is what's specified...

As it happens, I'll be running mine from a humistat and/or PIR/timer combo so can easily have a switched FCU instead of a 3P isolator - but for folks using the light as a trigger, it is all rather awkward.

As for cleaning, I dropped my S&P out of the duct (easy due to clever design) the other week and spent some time cleaning it as it was getting a bit noisy. 2 mugs or more of damp fluff came out after much work with a 1/2" paintbrush. Rodded the ducts for good measure.

That was after 6 years of service, so I'd say "monthly cleaning" was a bit excessive, but some cleaning is clearly required...
 01 February 2016 07:27 PM
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Zoomup

Posts: 3431
Joined: 20 February 2014

Originally posted by: peteTLM

It has been a favourite discussion point for them over the last few years, due to the insertion in the regs of the 'manufacturers instructions' line.

Would a plug top fuse really react faster than a type B mcb??

Would a motor in the fan which is the size of something out of a scaelectric toy car really cause overcurrent even if it was stopped dead? In my experience the components on the timer fry before anything else, if anything happens at all.



Why dont they make a fan isolator with a 20mm fuse in it? Or better still just make these rubbish fans a bit more substantial.


Well said Pete TLM. I entirely agree with you.

Thermal protection as well would be good to prevent the plastic melting when the fan gets full up with detritus.

Z.
 01 February 2016 07:29 PM
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Zoomup

Posts: 3431
Joined: 20 February 2014

Originally posted by: sparkiemike

Perhaps a 3A MCB


Perhaps a 0.3 Amp. m.c.b. Will a small bathroom fan ever draw 3 Amps?

Z.
 01 February 2016 07:37 PM
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Zoomup

Posts: 3431
Joined: 20 February 2014

Probably the 3 Amp fuse requirement is just to protect the small internal fan wiring, just like in central heating controls and valves. A 3 Amp. current can generate some significant heat. Over 700 Watts. That is enough to cause a fire in a plastic fan and the fuse will not blow at all whilst carrying 3 Amps.

Z.
 01 February 2016 07:59 PM
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aligarjon

Posts: 3875
Joined: 09 September 2005

Originally posted by: Zoomup

Probably the 3 Amp fuse requirement is just to protect the small internal fan wiring, just like in central heating controls and valves. A 3 Amp. current can generate some significant heat. Over 700 Watts. That is enough to cause a fire in a plastic fan and the fuse will not blow at all whilst carrying 3 Amps.



Z.




i ordered 10 vortice fans on-line last week as there is no fuse requirement with them. They cost less than £15.00 each, so hardly any difference in cost to the other rubbish out there that does.(they had the exact same model in Denmans who i use a lot for £35.00) plus vat A decent in-line is far superior if you have room. Again the vortice ones do not require a 3amp fuse and are superb. probably the best part of £50 but worth every penny.

Gary

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Specialised Subject. The Bleedin Obvious. John Cleese
 01 February 2016 08:00 PM
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aligarjon

Posts: 3875
Joined: 09 September 2005

Originally posted by: Zoomup

Probably the 3 Amp fuse requirement is just to protect the small internal fan wiring, just like in central heating controls and valves. A 3 Amp. current can generate some significant heat. Over 700 Watts. That is enough to cause a fire in a plastic fan and the fuse will not blow at all whilst carrying 3 Amps.



Z.


I have seen on some fans that the 3amp requirement is uk only.

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Specialised Subject. The Bleedin Obvious. John Cleese
 01 February 2016 08:08 PM
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Grumpy

Posts: 755
Joined: 09 January 2009

Hi Gary, do you think you could pm me a link to your source of fans?
Thanks. Grumpy

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Only dead fish go with the flow. Be a salmon!
 01 February 2016 09:50 PM
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aligarjon

Posts: 3875
Joined: 09 September 2005

Hi Grumpy. they are from a company called fastlec. i have used them several times with no issues. The fan is the Vortice punto 4" with timer. model number M100T-4T. £ 14.20 + vat each . just google them.

Gary

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Specialised Subject. The Bleedin Obvious. John Cleese
 02 February 2016 08:59 AM
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leckie

Posts: 4439
Joined: 21 November 2008

I use Vortice or Greenwood Airvac as neither require 3A fuses and both a very reliable.
 02 February 2016 05:39 PM
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KFH

Posts: 567
Joined: 06 November 2010

The Greenwood Halo range (fan and light in one unit) instructions shows a 3A fuse required in the supply. My customer wants a combined unit to replace existing fan which does not have a fuse in circuit and I suspect is not going to be happy if I add fitting one to the price for each of the two bathrooms.

I have been through a range of fitting instructions and have not so far found a combined unit which does not require a fuse.
IET » Wiring and the regulations » Bathroom lighting at 3A

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