Bathroom Extractor Fan - Shower Circuit ?

davidlizard

Hi,

As our bathroom gets steamy, I would like to fit an extractor fan. Ideally, I would like one that comes on when the shower is in use, and runs for a few minutes afterwards. The bathroom is immediately below the loft, and I plan to vent the steam out of the bathroom roof into the loft and through to outside.

I don't really want to fit one to the light as (a) the light is not always switched on during the daytime as the bathroom is very light anyway, and (b) I do not want the extractor to come on at night when someone uses the bathroom. We would prefer some kind of automatic option, as if we have to manually turn it on/off, we will forget.

A logical solution would therefore be connect it to the shower circuit. We have a 9.8kW electric (thermostatic) shower, which is on its own circuit (10mm2 cable), which runs into the loft from the consumer unit to a pull switch, then from the switch to the shower.

Would it be OK to put a fused (3A) spur in off the shower circuit cable (between the switch and the shower) and having the extractor running off that ?

Finally, I do not believe that this work will be notifiable under Part P, as all of the electrics will be outside of the bathroom (i.e. in the loft and not a special area). I usually run stuff past a mate who's a sparky (I fitted the shower and have rewired most of the house - he has checked it and completed the paperwork), but he is currently on a round the world trip.

All advice gratefully received.

ozskin

try a humidistat fan

Ystrad_Lad

Connecting additional circuits to an electric shower circuit is not allowed under regulations 314-02-01 to 314- 02-04 of BS 7671.

Extractor fans are normally designed to connect to lighting circuits and depending on how it's arranged you may be able to avoid a Part P notification.

davidlizard

Many thanks ozskin/Ystrad Lad. Will look at the humidity types as recommended - did not realise such things existed, which means I need to go nowhere near my shower circuit, and fit it onto my lighting circuit.

I have spoken again with the council today, and they are happy that as there is zero wiring in the bathroom, then its not notifiable (after some discussion!). If I fitted the unit onto the wall, then there would be, but its not a problem for the loft, and any pull switches are outside the bathroom.

Ystrad_Lad

Keep an eye out for an article on Extractor Fans due to be published on the following website soon. Issue 22 Spring 07 should answer most of your questions.

http://www.iee.org/Publish/WireRegs/WiringMatters/index.cfm