How do you wire an extractor fan within a lighting circuit?

[rudeboy500]

Hi Guys,
How do you wire an extractor fan within a lighting circuit? I have bought a 4in extractor fan i would ideally like to feed this through the lighting circuit. I have wired Lighting circuits and Ring Circuit at college but they have not taught us how to wire an extractors fan with timer this is new to me any diagrams and instruction will be a big help
Thanks
rudeboy500

 

[Des 56]

There are many ways of controlling a fan, people have their own favourite methods

There are also requirements specific to fans including means of isolation of all poles where required, and inclusion of fuses recomended by manufacturers and IP rated where req and trqnsformer locations if in a special location

Be aware of these needs before learning and deciding on type of control you decide to go with

 

[Davesheff]

Perm live from light switch ,switch wire&neutral from light,through a triple pole isolator to fan

 

[Baker1988]

Me personally i take a three core and cpc from the light pendant neutal, live ,swich live and take that to a triple pole isolater out side the bath room then from there to the extractor but thats just me.

 

[Geoffsd]

It will probably be complicated by the manufacturer unnecessarily requiring protection by a 3A fuse which, if you chose to follow and fit correctly, will mean a triple pole switch is not needed.

 

[Octopus]

Are there instructions in the box? If so they should given you tje answer regarding the wiring plus whether a 3A fuse is required.

 

[rudeboy500]

Hi guys, forgot to mention that I live in a bunglow so the wire to the lighting circuit is in the roof it has a junction box which is the live feed from the consumer unit is connected to the juction box, pull cord and light fitting,can i use the junction box and feed this through to the extractor fan via pull cord switch.
The fan is 9 foot away from the shower cubicle so therefore in am in zone 3 under special locations regulations.
Thanks
Rudeboy500

 

[brman]

you can connect where you like as long as it is done properly and any junction boxes are either maintenance free or accessible.
a pull cord is ok as long as it is triple pole.

btw. Given you are asking fairly basic questions I should ask if you are aware that work in a bathroom is notifiable? I am guessing you are not part P registered.

 

[MarkieSparkie]

Hi guys, forgot to mention that I live in a bunglow so the wire to the lighting circuit is in the roof it has a junction box which is the live feed from the consumer unit is connected to the juction box, pull cord and light fitting,can i use the junction box and feed this through to the extractor fan via pull cord switch.
The fan is 9 foot away from the shower cubicle so therefore in am in zone 3 under special locations regulations. You are outside the zones as there is no zone 3 in the 17th Ed of BS7671.
Thanks
Rudeboy500

See OSG 8.1 for details.

 

[rudeboy500]

hi markisparki, will look it up how about answering my pervious question your advice will be most appreciated
Thanks
Rudeboy500

 

[rudeboy500]

ok since everyone busy can some one direct me to a diagram they know of
thanks Rudeboy500

 

[sedgy34]

Hi Guys,
How do you wire an extractor fan within a lighting circuit? I have bought a 4in extractor fan i would ideally like to feed this through the lighting circuit. I have wired Lighting circuits and Ring Circuit at college but they have not taught us how to wire an extractors fan with timer this is new to me any diagrams and instruction will be a big help
Thanks
rudeboy500

take a 3core and earth from light to isolator then to your fan (3 core&earth)=live,neutral,switch live,earth. peice of cake (sponge) lol

 

[sedgy34]

you can connect where you like as long as it is done properly and any junction boxes are either maintenance free or accessible.
a pull cord is ok as long as it is triple pole.

btw. Given you are asking fairly basic questions I should ask if you are aware that work in a bathroom is notifiable? I am guessing you are not part P registered.

Hes not going to be any of what you stated if hes at colege and they havnt shown him how to wire a fan.

 

[nickblake]

It will probably be complicated by the manufacturer unnecessarily requiring protection by a 3A fuse which, if you chose to follow and fit correctly, will mean a triple pole switch is not needed.

dis agree with this part of your reply there is a reason why the fans have to be de rated and the reason is if the fan seizes to to lack of maintainance or a failure of the bearings etc which causes the fan to stop then the fan motor could over heat and catch fire this could be before a 6 amp or 10 amp mcb operates hence the reason it has been de rated i have been in a situation where this has happend and has set fire to a shop causing £89,000 worth of damage , also a fan in a toilet of a hair dressing salon luckly didnt cause much damage , and one main one was due to a fatal fire in which 3 people died in London which the spark was prossecuted , not sure what the outcome was this is the reason for derating

 

[rudeboy500]

hi Sedgy34,
when was it the last time you studied at college FYI i only do 3hrs in a week at college so we have to do a crash course mostly its based on Health & safety I am not in the electrotechnical trade as i have a full time job in a different profession I am in my last year and i have one more exam to go to finish in level 3 that in fact will make me an electricain in theory but not in practical terms.
To answer your question we only cover the basics eg: installation of Lighting circuit, Ring (final) Circuit inspection and testing and fault finding.
Thanks
Rudeboy500

 

[rudeboy500]

See OSG 8.1 for details.

Hi MarkieSparkie,
your right looked it up i knew there were 3 zones 0,1and 2
thanks for correcting me
Rudeboy500

 

[Geoffsd]

dis agree with this part of your reply there is a reason why the fans have to be de rated and the reason is if the fan seizes to to lack of maintainance or a failure of the bearings etc which causes the fan to stop then the fan motor could over heat and catch fire this could be before a 6 amp or 10 amp mcb operates hence the reason it has been de rated i have been in a situation where this has happend and has set fire to a shop causing £89,000 worth of damage , also a fan in a toilet of a hair dressing salon luckly didnt cause much damage , and one main one was due to a fatal fire in which 3 people died in London which the spark was prossecuted , not sure what the outcome was this is the reason for derating

That may be true. Is there evidence that a 3A fuse would have prevented the outcome?

The CU fusues/mcbs are there to protect the installation cables. These fans are not supplied with fitted 3A flex.

If the manufacturers produce products which are 1A (or even ¼A) then they should fit integral fuses rather than state that another accessory be fitted to the installation which is still three times (or even twelve times) larger than necessary.

I suggest that this tragedy would be due to the manufacturers' negligence were it not for 134.1.1 allowing them a cop-out and/or to produce shoddy goods.

That's what I meant by unnecessary.