Fan feed coming off switched shower pull cord ?

**chris76** · 20th July 2009, 09:05 AM

Hi guys. I've recently fitted a new shower and shower feed at home.Now the fan originally come on with the lights, but i was wondering if i could take my feed for the fan off the shower pull cord, so it only comes on with the shower.Its a 9.5kw shower with 40amp rcd protection 10mm cable. Any response would be appreciated lads!

**Ohmslaw** · 21st July 2009, 06:25 AM

Hi.

No, you cant do as you have suggested above.

Reason being that the 1.0mm or 1.5mm cable that you will use to feed the fan from the shower pullcord is no-where near large to carry the 40A in the event of a fault and therefore will melt before the overload protection kicks in.

My advice is to leave it as it is.

**chris76** · 21st July 2009, 08:10 AM

Originally Posted by Ohmslaw

Hi.

No, you cant do as you have suggested above.

Reason being that the 1.0mm or 1.5mm cable that you will use to feed the fan from the shower pullcord is no-where near large to carry the 40A in the event of a fault and therefore will melt before the overload protection kicks in.

My advice is to leave it as it is.

Thanks ohmslaw

**akaboosi** · 21st July 2009, 10:36 PM

You could break into the 10mm switch wire from the pull sw and joint box them so you have three cables at that joint - 1 from the switch, the second to the shower, and the third to a fused switch spur which then fuses it down to 3amp and a 0.75mm flex for a fan.

The joint box will be big and you need space for the bend in the cables as you're probably already aware and some big strip connectors or some other joining method!!!

There is always a way!!

**Ohmslaw** · 22nd July 2009, 06:32 AM

Really??

**cj-sharpy** · 25th July 2009, 12:21 PM

Originally Posted by akaboosi

You could break into the 10mm switch wire from the pull sw and joint box them so you have three cables at that joint - 1 from the switch, the second to the shower, and the third to a fused switch spur which then fuses it down to 3amp and a 0.75mm flex for a fan.

The joint box will be big and you need space for the bend in the cables as you're probably already aware and some big strip connectors or some other joining method!!!

There is always a way!!

Not a route I would go down. Adding joints and junctions where they are not neccesary is something I have always avoided as they are just additional weak points. and as said previously yor jumping from a 10mm 40A cable to at most a 1.5mm cable. If 40A went through that under a fault then it would melt and burn the guys house down.
I'd leave it coming from the lighting circuit as it is.

Besides you'd have to turn the shower on everytime you have a smelly poo!

**Greg** · 26th July 2009, 08:34 PM

For the sake of good practice I would say don't do it because its just messy, but in theory if you were to take a 10mm feed from the pull cord to a fuse spur then the 1mm cable would be sufficiently protected by a 3a fuse. What people are saying which is very true is not to downsize cables which are not designed to carry the load in which the circuit is protected by.

**bredwin** · 27th July 2009, 04:00 PM

Originally Posted by cj-sharpy

Besides you'd have to turn the shower on everytime you have a smelly poo!

Nicely put!

I always find a seperate DP switch for the fan so that it can be switched on in such instances is the best way to go. Can't really undertsand what you'd gain from bringing it off the shower circuit.

**Besoeker** · 2nd August 2009, 04:09 PM

Originally Posted by akaboosi

You could break into the 10mm switch wire from the pull sw and joint box them so you have three cables at that joint - 1 from the switch, the second to the shower, and the third to a fused switch spur which then fuses it down to 3amp and a 0.75mm flex for a fan.

The joint box will be big and you need space for the bend in the cables as you're probably already aware and some big strip connectors or some other joining method!!!

Where would you put all this?

**darkwood** · 3rd August 2009, 08:24 PM

Originally Posted by chris76

Hi guys. I've recently fitted a new shower and shower feed at home.Now the fan originally come on with the lights, but i was wondering if i could take my feed for the fan off the shower pull cord, so it only comes on with the shower.Its a 9.5kw shower with 40amp rcd protection 10mm cable. Any response would be appreciated lads!

Above idea not good how about changing fan for one with humidistat fitted, it will work as is now but if humidity rises i.e. shower on then it will run until low again but will require a permanent feed if existing wiring does not have one which can be taken from lighting circuit.