Wiring bathroom extractor fan with humidity or PIR sensor

[Nick Robinson]

Seen several posts on extractor fans but none that answer my specific query. I hope someone can help.

I want to fit an extractor fan in the bathroom of a period conversion flat.

Bathroom ceiling is old lath and plaster and there is no access from above (upstairs flat) so wiring into the lighting circuit would involve major work.

To get round this I thought about fitting a fan with either a humidity or PIR sensor and wiring it into the ring main.

I understand I would need to fit a FCU outside the bathroom to comply with regs but what would be the wiring arrangement from the FCU to the fan?

Nick

[Lurch]

On 28 May 2004 16:49:25 -0700, st [e-mail] (Nick Robinson) strung together this:

Yes, with a double pole switch.

A length of 1mm twin and earth.

[BigWallop]

Where is the light fitting on the ceiling in relation to where you want the fan to be ?

Most extractors for a bathroom will have an over-run timer unit on it, so will you be using this type of fan ?

Do you want the fan to switch on everytime the light is switched on ?

Do you want to cut access through the lath ceiling to be able to pull cables. Lath and plaster ceilings have good void space for this job.

Are you running the cable on the surface of the walls or ceiling within a trunking system, or would you be burying the cables under the plaster ?

Do you have any experience of wiring appliances directly to Fused Connection Units (FCU) ?

[Graham Wilson]

You might find a PIR sensor frustrating. You pop in for a quick tiddle and the fan switches on in the middle of winter pushing lots of hot air out of the house.

How about a switch with an over-run option.

Graham

[nightjar]

I have a humidity sensor controlled fan in my bathroom and I find it very effective. It is an extra low voltage fan, so the wiring from the transformer to the fan is run in an odd bit of low voltage stranded twin flex that I had lying about. I think it was speaker cable. The FCU (3A fuse) and the transformer are connected with a bit of 1mm lighting cable.

Colin Bignell