Fan feed coming off switched shower pull cord ?

[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!

[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.

[chris76]

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]

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]

Really??

[cj-sharpy]

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]

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]

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]

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]

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.

[max power]

are you crazy you cant take it off a shower supply. FAN 6AMPS SHOWER 45AMPS are you trying to burn your house down

[darkwood]

are you crazy you cant take it off a shower supply. FAN 6AMPS SHOWER 45AMPS are you trying to burn your house down

The crazy bit i agree with but only cos it would mean a undersized cable been protected by an oversized fuse, if their was a fault on the small fan supply wire from the 10mm joint as it could cause a fire but the fan is prob' about 30w taking about 0.12amps so it would work but be unsafe in fault conditions.

[akaboosi]

Where would you put all this?

Obviously would depend on the where the shower room was. If its down stairs it would be a problem but if it its upstairs and you have a big enough attic then whats the problem. Although I do realise that if you have a smelly poo as some other reader pointed out then you would need your showwer switch on to get rid of smelly fumes.