Dimmer for Bathroom Led Lights With Extractor Fan


Postby mblument » Mon Mar 19, 2018 7:17 pm

Hello,
I have read through the https://www.diydoctor.org.uk/projects/di ... itches.htm section,
thank you.
To clarify, for safety, please add the answer to this specific change with bathroom lighting.

I would like to change the single plate switch to a dimmer switch to reduce / dim the lightning in the bathroom (3 wires)
- Existing 1 common brown wire and 1 one blue wire, and 1 green yellow earth wire ground
- Earth wire attached to the faceplate and the face plate is METAL. - Gang box is plastic
- New dimmer is "Varilight JQP401W V-Pro 1 Gang 2-Way LED Trailing Edge Dimmer Switch" PLASTIC
- Dimmer has only attachment TWO wires, No earth,.
- I dont care if the fan slows down with lights on dim,

!!* Please advise that I can cap off the earth wire, and install the new dimmer as the faceplate is plastic, or is it different for bathroom regulations?

Thank you for any help.
Mark
mblument
Rank: Labourer
Progress to next rank:
50%
Posts: 3
Joined: Mon Mar 19, 2018 6:52 pm

Sponsor

Simply Build It

Postby Mr White » Mon Mar 19, 2018 10:08 pm

Depending on how the fan is connected / wired you may get one or more of the following

1) Fan will not work at all
2) Fan will stall / over heat
3) Fan will run and damage your dimmer.

Most fans are not designed to work with ordinary dimmer switches. You should get the lights separated from the fan if you really must dim the lights.
Mr White
Rank: Foreman
Progress to next rank:
16.7%
Posts: 250
Joined: Tue Jun 20, 2017 9:54 pm

Postby mblument » Mon Mar 19, 2018 10:49 pm

Thank you So much for responding!
I will try and see what happens.
I assume you agree that it is okay to The earth wire, however using a dimmer may be detrimental to the fan and or the circuit and harm both, but it's not an issue from a safety point.
Kind regards
mblument
Rank: Labourer
Progress to next rank:
50%
Posts: 3
Joined: Mon Mar 19, 2018 6:52 pm

Postby ericmark » Thu Mar 22, 2018 10:20 am

The earth wire simply put in a connector block or fold over and tape, clearly leave it there in case wanted latter.

Most fan will produce a back EMF when switched off, so be it a dimmer or not putting an LED bulb and fan on same circuit could cause a problem, it depends on how the LED is current regulated, however likely it will work. But any ones guess to how long.

There seems to have been a tradition to wiring fans to lights, the building regulations are split into parts, the Part P refers to electric but with the bathroom fan it is the other parts which become a problem. Can't remember exact wording but the main points are.

1) The fan must not cause fumes to be drawn into the house, in general not a problem with central heating, but gas fires often have what is called an open flue, not really open, it's just that they draw combustion air from the room, so extractor fans, tumble driers and like can draw fumes into the room.
2) If you have an opening window a fan is not required, so you can wire any way you want, but with out that opening window the fan needs turning on when items are used in the room, if no window then coming on with lights is OK. But if there is a non opening window, you need to be able to switch on fan without the lights. In real terms daft, as I know after a shower I switch on fan isolator and then flick lights on/off to help dry the room. But the reverse is also true, the fan does not need to be connected to lights, a simple push button for fan is enough.
3) Today we seem to be mad about not releasing energy, so there is a move to the heat recovery unit, idea is hot air going out heats the cold air coming in, there are two versions in general, those with two fans that pump air in and out, and those with a single fan which pump air one direction only and rely on pressure in room (or de-pressure) to force air in other direction. The latter use the pipe through the wall as a heat exchanger and look just like a standard fan.

Remember a tungsten light bulb only wastes energy if you don't want the energy it releases, so in a bathroom the inferred light actually warms out body direct, and so in the bathroom the tungsten bulb can be looked on as energy saving. It safes energy because the bathroom can be kept at a lower back ground temperature when not in use, inferred heat is instant so far more efficient.

I have changed to LED bulbs, not to save energy but to reduce maintenance, but if changing causes a problem, then simply answer is don't change, in doors changing to LED lighting only transfers where the heat comes from, since gas is cheaper than electric yes saves a little money but the lights are only used in the dark, so what we had was a boost of heat in the evening, the inferred heat does not work a thermostat very well, so we got warmer house in evening then in the day. So to compensate when fitting lighting which gives off no heat, we need to fit programmable thermostats.
ericmark
Rank: Project Manager
Posts: 1913
Joined: Fri Oct 02, 2009 8:49 pm
Location: Mold, North Wales.

Postby mblument » Thu Mar 22, 2018 5:56 pm

Thank you for your clear and thorough explanation !
mblument
Rank: Labourer
Progress to next rank:
50%
Posts: 3
Joined: Mon Mar 19, 2018 6:52 pm

Postby DaveyTed » Fri Mar 23, 2018 4:34 pm

You mention a plate switch for the lights. Surely in a bathroom it should be a pull cord switch for the lights?
DaveyTed
Rank: Apprentice
Progress to next rank:
10.5%
Posts: 7
Joined: Thu Mar 22, 2018 7:02 pm

Postby Mr White » Fri Mar 23, 2018 9:21 pm

DaveyTed wrote:You mention a plate switch for the lights. Surely in a bathroom it should be a pull cord switch for the lights?


No. (and don't call me Shirley) You can have a "plate switch" in a bathroom, so long as it not in any of the excluded zones.
Mr White
Rank: Foreman
Progress to next rank:
16.7%
Posts: 250
Joined: Tue Jun 20, 2017 9:54 pm

Display posts from previous
Sort by
Order by



  • DIY How to Project Guides

  • DIY how to tutorial projects and guides - Did you know we have a DIY Projects section? Well, if no, then we certainly do! Within this area of our site have literally hundreds of how-to guides and tutorials that cover a huge range of home improvement tasks. Each page also comes with pictures and a video to make completing those jobs even easier!



 


  • Related Topics