Extractor fan

[tmansteve]

Hi All

I have an extractor fan connected to the lights in the bathroom. So that they don't have to come on everytime you switch the lights on, can it be wired to the shower switch so you use it only when you have a shower?


Steve

 

[RobFurn]

No im afraid not, your MCB (Fuse) for the shower will be too higher a rating to protect the cable going to your Fan.

 

[tmansteve]

Many thanks.

It was a long shot but I thought it might be just too much for it. Is there any other way or should I stick with what I've got?

 

[RobFurn]

Stick with what you have got or

Completely change your setup. Replace your timer fan with one fitted with a humidistat or pull cord. From your lighting circuit connect to a Fan Isolator outside the bathroom then from the Fan Isolator to the fan.

 

[Mark1972]

How about using a fused spur? I recon you might be able to get two 6mm in your average 45a pullcord. So out of the switched side into a fused spur, then fuse it down to 3a for the fan? All assuming it's 6mm - which it probably isn't!

What does everyone think?

 

[RobFurn]

So long as you use a switched fused spur and put it outside the bathroom I suppose that will do as a fan isolator, trouble is its still a lot of work getting back from there to the fan you may as well do the whole lot again.

 

[Steve]

It IS possible:

Have I got this right? I'm sure ban-all-shed's version was more complex. His pictures have disappeared .

This way the shower is powered from the lighting circuit, saving trying to fit an FCU on 6 or 10mm cable. It will run the fan for the duration of the shower, and overrun after the shower switch is turned off. Dont forget the fan isolator between the ctr and the fan! And any overcurrent protection under 5 amps must go before the contactor.

 

[ashm]

This seems to be exactly what i wanted to do, am i right in thinking the contactor in enclosure is a relay? any ideas where such a device for this application can be purchased?

 

[Steve]

http://www.tlc-direct.co.uk/Images/Products/size_3/HGES220.JPG

Hager 20 amp 2 pole contactor. You only need use one pole. The wiring diagram on the front of them is pretty self explanatory.

Bear in mind, this falls into the "professional" or advanced wiring category. These sorts of things are normally only fitted by pro's, but it is fairly simple to do if you understand the theory and logic behind it.

 

[ashm]

Not seen one of them before, it looks like it belongs in a CU,is that correct? or can it be fitted somewhere near the shower/fan i.e in the loft

 

[ashm]

after looking at your diagram again, i'm guessing the "in enclosure" bit implies it would be fitted in the loft or similar and enclosed in something similar to this.........

is this correct?

 

[Steve]

Not seen one of them before, it looks like it belongs in a CU,is that correct? or can it be fitted somewhere near the shower/fan i.e in the loft

It can be fitted in a CU, it mounds on the DIN rail. But you can get an enclosure with a DIN rail, with a closed front. You can also get terminal blocks that are DIN rail mountable to make everything tidy! And MCBs will also fit, so you can build in protection. But as I said, these are professional, almost specialist parts and not all places will stock them.

 

[ashm]

thanks for the info.Tidies the way forward! second only to safe!