Bathroom Fan

[levstar]

Hi Apologies in advance, yet another post on this subject. Although I have received some confusing advise and wanted to get some feedback.

I have purchased a 20A fan for my bathroom and was going to wire up as per image: http://www.diynot.com/network/levstar/albums/

With one exception in that the permanent feed on the loop in already has 3 wires Loop in. Loop Out and Live to the Switch. Can I add a fourth wire in here to provide permanent live for the fan.

I have also been advised that in between my feed from the light to the isolator I will need a 3A FCU.

Is this right???

P.S I was planning to use 3 core + earth 1.5mm

Many Thanks

 

[ban-all-sheds]

I have purchased a 20A fan for my bathroom

20W, I hope, not 20A....

and was going to wire up as per image: http://www.diynot.com/network/levstar/albums/

With one exception in that the permanent feed on the loop in already has 3 wires Loop in. Loop Out and Live to the Switch. Can I add a fourth wire in here to provide permanent live for the fan.

What exception?

That diagram shows a rose with 3 original conductors in one terminal - loop in, loop out and switch, with a 4th added for the fan.....

I have also been advised that in between my feed from the light to the isolator I will need a 3A FCU.

Is this right???

Advised, or is that what the instructions say?

If you put it between the light and the isolator you'll need 2 FCUs, one for each live, which is a bit messy.

If you do need an FCU, you can change how the light is wired and put it and the fan on the FCU:

or, if you change the switch to a DP one you can wire it like this, which means that the light is not on the fan fuse and has the added bonus of no longer needing a 3-pole fan isolator:

P.S I was planning to use 3 core + earth 1.5mm

Yup.

Don't forget that however you do it it's notifiable.

 

[holmslaw]

..

 

[levstar]

Thanks for this info guys, yep I meant 20w...fat fingers..

I have a 3 pole isolator, the instructions do not mention an FCU so I am unclear why I would need one if I wire as per the original diagram.

 

[ban-all-sheds]

That is very dangerous, two points of isolation should never be created.

Where are there two points of isolation?

 

[holmslaw]

..

 

[levstar]

Great thanks for this.
However being keen to learn I am entriged how the diagram in http://img109.imageshack.us/img109/3333/fandiagram.jpg would be wired in 3 core + earth when we are dealing with a loop in / loop out light.

Are we saying The Feed In goes to > FCU > Switch > Isolator > Light

thus ensuring the switched live is also fused down to 3A unlike my original suggestion where the switched live would have been 6A

in between my feed from the light to the isolator I will need a 3A FCU.

If so where would the permanent live be taken from to go to the next light.

Cheers

 

[ban-all-sheds]

I am entriged how the diagram in http://img109.imageshack.us/img109/3333/fandiagram.jpg would be wired in 3 core + earth when we are dealing with a loop in / loop out light.

Put the loop through a 3-terminal JB, take a cable from there to the FCU and then to the existing rose, and then take 3C+E from the rose as normal. (That diagram could be better - it doesn't show that the FCU is a DP device or that the fan cable is best connected at the rose.)

PS- ignore holmslaw's comment about 2 points of isolation - he doesn't know what he's talking about.

 

[levstar]

Got it cheers