Bathroom extractor fan and dimmer light switch

The fan can most certainly be wired from a separate switch if desired, the answer to this really depends on what functionality you want the fan to have, your builder is right to an extent as most fans come on with the light and this is certainly not acceptable to have a fan connected to a dimmer because dimmers vary the power output. If you are happy for the fan to come on separate from the light switch I would suggest buying a pull cord fan for a wall, this has a permanent supply to it and is switched on and off via pull cord on the fan its self, other options include humidity sensor fans these also have a permanent supply to them which can be run from the fuse board to your fan isolator and then to the fan, humidity sensor fans will only come on when the humidity in the room reaches a set level, the level of humidity the fan comes on at can also be adjusted via a dial on the inside these are perfect for ceiling fans but come at more of a cost than a standard pull cord fan. If you already have a standard fan you can simply have a separate switch for it ran independently of the dimmer switch such as a separate pull cord inside the bathroom. Please note that your dimmer switch should be outside the bathroom and any lights should have the appropriate IP ratings for the given zone they are in. Hope that helps, Charlie. Megson Construction And Property Maitenance

If you want to know about the ins and outs of electrical work in a bathroom-why not ask a registered electrician as opposed to a builder. The electrician would know the regulations as in your case it's work in a special location you need a certificate and notification to Building Control, something I doubt the builder could supply. You will also receive some sound advice, options, as well as the job being done up to scratch and more importantly safely.

I can't add much more to the answer given by Deacon Electrical Services other than to say that since customers would not normally approach a professional electrician for advice regarding building work, it therefore makes no sense that they should ever seek advice concerning electrical installation work from builders!

As everyone else has said speak to an electrician at your property. Most electricians who work on domestic properties have very inventive minds and can find solutions to most problems, you'd be amazed at some of the things we are asked to do. (installing a TV opposite the toilet is amongst my top 10) I know I hate saying no to anything.

How big is your bathroom? Switches can not be installed in Zone 1 or Zone 2 unless they have an IP rating of IPx4. Normally dimmer switches do not meet this requirement. Your Extractor should have a external isolator and be fused as per the manufactures instructions. This is usually a 3 amp fuse. As far as I know there is no requirement for the extractor to be installed on the same switch as the lights. Geoff