wiring in a wall extractor fan

[FieryJack]

I've bought a 20W Manrose wall extractor for my cellar and am after advice for the best way to connect this. The instructions say "the fan must be connected to a double pole fused spur" so I've purchased the appropriate switch.

My question is what's the best way to get this connected? I know the answer is "get a qualified electrician", but I want to be sure whoever does it is doing it the best way too. I believe I have the following possible options for making the connection:

* direct to the consumer unit, which is also in the cellar and has a spare MCB (I think that's the right term).

* add a spur off the back of a dual 13A socket

* spur off the fluorescent light that's also in the cellar

Suggestions please.

 

[Maxxy]

When do you want it on, all the time, only when you flip a certain switch for it, or only when the lights on?

20W sounds tiny by the way...but i dont deal in fans so maybe its just me

 

[JohnD]

I would say either the lighting circuit or a spur from a socket, whichever is closer and easier. If the lighting has an exposed junction box, or a big roomy rose, that might be very handy.

No need to go back to the CU.

BTW the lighting circuit is (I presume) already fused down to 6A, so does not really need an FCU with its own fuse, but it will do no harm.

 

[BigJon]

Regardless of where you feed it from i'd advise you to have local isolation, install it thru a 3amp FCU for maintenance purposes

 

[ricicle]

If you use the fuse connection unit with as small fuse rating as possible you shouldn't lose your lights if the fan develops a fault (If fed from lighting circuit)

Ricicle

 

[FieryJack]

Thanks for the replies.

I should have said the fan is controlled by a humidity sensor, so it should come on as required. The cellar isn't dripping with damp, far from it. I just want to maintain the environment to be nice and dry, so I think 20W will do the job. Well, the guy in the shop seemed honest and reckoned 20W would be fine.

The light does not have a rose. But I suppose that could be added in?

The wiring diagram for the fan says there should be 2 live feeds, one switched and the other permanent. Is that easy enough to put in to the lighting circuit?

 

[JohnD]

The "switched live" is normally conected to the lighting circuit, so that the fan comes on when the light is switched on (this method is frequently used for bathroom fans).

I understand that you want to be be on all the time, subject to the integral humidity sensor, so you will need to have a bit of a look at the instructions leaflet. You may or may not want the "switched live" permanently on (it may or may not override the humidity sensor, I don't know).

20Watt should be plenty unless the cellar is very large - most bathroom fans are no more.

Remember to provide "air in" ventilation at the opposite end of the cellar so that you get a flow or air.

 

[BigJon]

If you dont have a ceiling rose, then hopefully if you open up your light switch you will find neutrals in a connector block- if this is the case you will need to take a 3core Twin and earth to a fan isolator then a flex from the isolator to your fan. If you dont have neutrals at the switch there must be a join somewhere and you will get a feed/sw.feed and neutral from there.