Dimmers in bathroom

Discussion in 'Electricians' Talk' started by DedicatedDIYer, Aug 16, 2021.

  1. DedicatedDIYer

    DedicatedDIYer New Member


    Planning a bathroom refurb, want to know options.

    There will be 2 dimmers outside the bathroom to control the ceiling lights and wall lights separately. Can they be wired so that when either of the dimmers is 'switched on', they also activate the extractor fan and a pair of demister pads (for mirrors)?

  2. Ind spark

    Ind spark Screwfix Select

    Not 100% on that one, I would say no because you'd be dimming the fan and Iv never done that before.
    You'll get some better answers soon I'm sure.
  3. Xshaunyx

    Xshaunyx Member

    Like ind spark said dimming the supply to the fan wouldn't be a good idea you can get a 2g switch that is half dimmer and half normal switch perhaps that's an option
  4. Bob Rathbone

    Bob Rathbone Screwfix Select

    Put the fan on a PIR occupancy sensor, then you will have no issues.
  5. Fusebox Wales

    Fusebox Wales Member

    What you want can be achieved, but only with a bit of additional work. As Ind Spark said, if the fan comes off the dimmer switch, it will not function correctly because the fan needs the full supply. Options above are good ones - either have a standard switch which turns the lights & fan on and then a separate dimmer switch, down stream of the standard switch, which adjusts the brightness of just the lights. Or, use an occupancy switch to trigger the fan. Alternatively, just have a separate switch for the fan so that you can turn it on and off as you require, independently of the lights.
  6. MGW

    MGW Screwfix Select

    Some old dimmer switches were two independent units switch and dimmer built into one face plate, so it could be done, however when the Parts of the building regulations first came out, they required that if there was natural light the fan needed to be turned on without turning on the lights, two pole switches were common, but on subsequent re-issue of the regulations this requirement was dropped, likely as LED lights use so little power. But there is no requirement for the fan to work with the lights, with an opening window you don't need a fan, so you can do what you like, but where a fan is required by building regulations you need a run one device etc, but it does not need to be on the lights or even automatic, a pneumatic push switch would do.

    I have had no end of problem switching LED lights with neutral less electronic switches, flashing when switches off, a shimmer when switches on, and started with 5 electronic switches, now down to two. It seems there is no standard for a dim-able bulb. Yes EU rules said they needed to say if not dim-able, but they don't need to say how you can dim the bulb, so be it a variable transformer, or leading edge or trailing edge, if it needs a load capacitor the bulb manufacturer does not need to tell you.

    So my wife wanted a fancy chandelier, it used G9 bulbs which I did not like, but she was assured it would work with LED bulbs, so she started with the small bulb shown G9-comp.jpg which flashed when switched off, so fitted a load capacitor load-capacitor.jpg this stopped the flashing but not easy to fit, not much room in the fitting, but when switched on there was a shimmer, so she got the larger bulb, one failed so I opened it to see what was inside, the smoothing capacitor that stopped the shimmer was larger then the whole of the small bulb. But the covers no longer fit, in a bedroom not such a problem, in a bathroom it would change the IP rating.

    In the living room my daughter gets a headache if main lights are on, likely a 100 Hz flash, does not effect my wife and I, but 8 bulbs, and with her bedroom 5 bulbs, so buying multi bulbs to give it a try gets expensive, and so we have decided if we want to remotely control a light, be it colour changing or dimming, we want a colour changing or dimming bulb, forget the dimming switch or smart switch, getting bulbs to work with them is too hard.

    We got a three GU10 spot light set from Lidi, complete with three zigbee smart bulbs and a remote control, actually we use the remote with other smart bulbs, but since the remote control is battery powered you can safely have it inside the bathroom, and use standard on/off switch.

    I will admit I got it wrong buying remote controls, I got two Remote1.jpg remotes with idea of working landing lights, it said zigbee 3 but it seems it was to work a lighting relay which was zigbee 3 the remote is not zigbee, I am crossing my fingers as also order a relay to fit inside the light, so I hope the remotes will work it?

    But having a remote control in the light or having smart bulbs you can still use a standard switch outside the bathroom to work light and fan, the old dimmer switch was great in the 80's, but things have moved on, and I will admit at 70 having a problem keeping up with it all.
  7. DedicatedDIYer

    DedicatedDIYer New Member

    Thanks everyone. I've decided to have 2 dimmers just for the 2 groups of lights, and a switch (located above the bathroom door) to activate the PIR sensor, which will control the extractor fan and demister pads.

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