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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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 02 February 2012 10:21 PM
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lyledunn

Posts: 1107
Joined: 13 August 2003

A local contractor was collared during an annual inspection visit by one of the better known approvals lot because he had fitted bathroom fans to 12 dwellings with incorrect overcurrent protection. The manufacturer of the fans, which have run-on timers, recommended 3A protection. The lighting in the bathroom is via a 6A type B mcb and the consumer units are located for ease of access in the hallway. Remedial action was insisted on. The suggestion by the inspecting engineer to run the supply for the bathroom lighting through a switch fuse containing a 3 A fuse was accepted and carried out. Where is the switch fuse located? Beside the fan isolator at high level in the bathroom! Were the remedial repairs acceptable? Indeed they were. Overcurrent issue sorted but access issue....well right down the toilet!

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Regards,

Lyle Dunn
 02 February 2012 10:43 PM
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peteTLM

Posts: 3715
Joined: 31 March 2005

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.

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Lack of planning on your part doesn't make it an emergency on mine....

Every man has to know his limitations- Dirty Harry
 02 February 2012 10:45 PM
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sparkiemike

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Joined: 24 January 2008

Perhaps a 3A MCB
 02 February 2012 11:12 PM
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mikejumper

Posts: 2416
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Originally posted by: peteTLM
Why dont they make a fan isolator with a 20mm fuse in it?

Wouldn't it need two fuses though, one for permanent live and one for switched live?
 02 February 2012 11:36 PM
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alancapon

Posts: 6882
Joined: 27 December 2005

That would depend on where the fuse was fitted. If you choose to put the fuse before the light-switch, then you could provide the permanent live and switched live off the same fuse.

Regards,

Alan.
 02 February 2012 11:40 PM
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peteTLM

Posts: 3715
Joined: 31 March 2005

Originally posted by: mikejumper

Originally posted by: peteTLM

Why dont they make a fan isolator with a 20mm fuse in it?


Wouldn't it need two fuses though, one for permanent live and one for switched live?


just the one, you would only use 1 fcu as an outboard item, just needs some thought

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Lack of planning on your part doesn't make it an emergency on mine....

Every man has to know his limitations- Dirty Harry
 03 February 2012 12:22 AM
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Dale76uk

Posts: 412
Joined: 04 February 2010

hardly worth bothering about. do you install fcu's for luminaires??? nope
 03 February 2012 09:16 AM
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impvan

Posts: 922
Joined: 07 September 2005

Or the specifiers could choose decent fans....

The Xpelair DX200T has 20mm fuseholders built-in.
 03 February 2012 10:31 AM
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sparkingchip

Posts: 9962
Joined: 18 January 2003

That is my take, go for fans that don't stipulate a 3 amp fuse in the instructions.

If 3 amp MCBs were readily available from more manufacturers I would go down that route.

Andy
 03 February 2012 11:44 AM
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impvan

Posts: 922
Joined: 07 September 2005

I've got quite a few 4 Amp hager breakers if you want to be 2/3 less naughty :-)
 03 February 2012 12:56 PM
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sparkiemike

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Joined: 24 January 2008

MK do 3A breakers, have used this solution myself
 03 February 2012 03:37 PM
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pyropot

Posts: 28
Joined: 14 March 2011

Originally posted by: sparkiemike

MK do 3A breakers, have used this solution myself


Did you use these to cover the whole lighting circuit? Did they have any problems with overload or nuisance tripping?
 03 February 2012 04:35 PM
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sparkiemike

Posts: 1630
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The whole circuit. To be fair it only had 3 fittings and the fan. But a lot of 3 bed homes will only have

3 bedroom light
1 bathroom light
1 fan
& maybe a landing light

Well below 3A (690W@230V), even more so if low energy lighting is used.

Edited: 03 February 2012 at 04:46 PM by sparkiemike
 03 February 2012 04:53 PM
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weirdbeard

Posts: 3116
Joined: 26 September 2011

Hi all, I know this might seem a bit picky, but if the manufacturer says there must be a 3A fuse, does a 3A MCB count as a fuse?

Looking at basic 4 inch timer fans, I have only found that ventaxia don't specify a fuse size in the instructions, they have a diagram in fig. 4 of the link below showing direct connection to a switched lighting circuit via a 3pole isolator:

http://www.vent-axia.com/files...-downloads/439014.pdf



Expelair say: " For fixed wiring circuits the protective fuse must not exceed 5A:

http://www.tlc-direct.co.uk/Te...ets/Xpelair/DX100.pdf




These other examples all they need a 3A fuse

GET- "double pole fused switched connection unit fitted with a 3amp fuse":

http://www.schneider-electric....slc,%20gfanc4sltc.pdf

Greenbrook: "double pole switched fuse connection unit...fitted with a 3 amp fuse. "

http://www.greenbrook.co.uk/product-pdfs/C100_Ins.pdf

Manrose: "double pole isolating switch...must be used with a 3 amp fuse"

http://www.manrose.com/specifi...ons/100mmfanrange.pdf

Airflow: "The unit shall be connected to a double pole isolating mains switch.... An external 3A fuse is required"

http://www.tlc-direct.co.uk/Te.../Aidelle/iCON_230V.pdf

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:beer)
 04 February 2012 05:21 PM
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slittle

Posts: 3678
Joined: 22 November 2007

We always stick a switched fcu outside the bathroom and feed the bathroom light through it (including the fan) (with a 3a fuse in it)

I understand there have been several insurance claims after fans caused smoke damage, Not following the instructions could prove costly.


Stu
 04 February 2012 06:20 PM
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weirdbeard

Posts: 3116
Joined: 26 September 2011

Originally posted by: slittle


I understand there have been several insurance claims after fans caused smoke damage,



There are some links to bathroom extractor related fires on page 2 of this recent similar topic:

http://www.theiet.org/forums/f...id=205&threadid=44616


Not following the instructions could prove costly.



I have just noticed in the expelair instructions link from my previous post at the top of page 7, that they recommend the fan is cleaned once a month and in big bold letters below it says "A QUALIFIED ELECTRICIAN MUST CARRY OUT ALL CEANING" !!!

Thats a get-out clause if ever there was one!!

Think I will go with ventaxia from now on!

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:beer)
 04 February 2012 11:04 PM
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DR2366

Posts: 711
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S&P fans I think don't specify a 3A fuse.
 05 February 2012 01:59 PM
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weirdbeard

Posts: 3116
Joined: 26 September 2011

Doh! There goes my ventaxia plan - the instructions for this model says " This fan should be provided with a local isolator switch fitted with a 3 Amp fuse capable of disconnecting all poles"


http://www.vent-axia.com/files...-downloads/427300.pdf



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:beer)
 05 February 2012 02:08 PM
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weirdbeard

Posts: 3116
Joined: 26 September 2011

Doh again! It gets worse - The instructions for this ventaxia model (VA100) says "Wiring should be via a switched spur with a 1A fuse"

http://www.e-tradecounter.co.uk/PDF/s-407.pdf

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:beer)
 05 February 2012 02:53 PM
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DR2366

Posts: 711
Joined: 09 April 2006

S & P fans

Only a 3mm gap, no 3A fuse
IET » Wiring and the regulations » Bathroom lighting at 3A

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