Wiring a 240v Extractor fan to the existing lighting circuit

Russky72 · Joined: 24 Aug 2009 Posts: 2 Location: United Kingdom

I have a good grounding, but I would still consider myself to be a novice!!!!

I am in the process of adding an Extractor Fan to the lighting circuit in the bathroom. The lighting wiring is modern and consits of a brown, blue and naked earth. Can I add the extracter fan to this by adding in the corrosponding brown and blue from the lighting to the fan? There is a permanant live which needs to be added as it is a timer fan.

The fan has a Live, Neutral, Permanant Live.

Is there anything else I would need to consider?

ericmark · Posted: Mon Aug 24, 2009 9:51 am

Russky72 wrote:

Is there anything else I would need to consider?

Yes the local authority building control (LABC) charges are in most areas over the £100 mark and one can often get the job done for less than the LABC charges so DIY is not economical.

I think Part L1 covers the rules for extra fans from memory too methods either continuous or with 15 min run on.

Either way line feed is required. On standard wiring this will be found on centre terminal of ceiling rose. But with ELV lights sometimes found in light switch or junction box.

There are loads of pictures and instructions on the Wiki: and
Sticky: part of site.

Russky72 · Joined: 24 Aug 2009 Posts: 2 Location: United Kingdom

Thanks for the prompt reply, the lights in my bathroom are spots (6 of them) with a 12v convertor behind them. Are they likely not to be in a ring circuit? If so, how will this impact on the wiring of the extractor fan? Can I link the fan directly to the wires of one of the spots, (before the convertor)??

Chri5 · Posted: Mon Aug 24, 2009 12:35 pm

Do you intend to have the extractor work on / off with the lights (A)or do you intend to use the overrun facility (B) ?

(A) = simple connection of the extractor to any 230v feed before any light transformer

(B) = same as (A) plus a further wire to the non switched / permanent live

ColJack · Posted: Mon Aug 24, 2009 12:37 pm

firstly, the naked earth shouldn't be naked.. put some sleeving on it..

you can connect the fan to the supply side of the transformer, but that won't get you a permanent live.. for that you should connect at the switch.. but that likely won't get you a neutral....

sparkwright · Posted: Mon Aug 24, 2009 7:32 pm

you need to find a point on the circuit where you can obtain ALL of the following;
permanant live
bathroom switched live
neutral
earth

this should be either at;
a junction box
the switch

remember to fit a 3 pole isolator switch to isolate the fan.
will the 240 v fan be well away from the bath/shower?