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Firstly I'm crap at DIY, secondly yes I should probably get a sparky in but I'm hoping STW can clarify it for me instead...
I have a dimmer switch in the house (that controls one of two lights in the living room), I want to change it to a normal switch (1 gang) so I can use a Hue bulb in it and control with Alexa. Also (may or not be relevant) the dimmer has always been odd in that when on the light bulb will occasionally go brighter or dimmer on it's own.
I also bought a cheap multi-meter just to reassure me when I'd turned of the light circuit at the fuse box (never used one before though...)
I unscrewed the dimmer switch at the wall and stuck the multi-meter probes on it and it was showing a voltage, think up to about 190 (as expected, although it seemed to fluctuate a lot). I then turned off the light circuit at the fuse box and checked again, seems to register between 0 and 0.6v now - was expecting constant 0??). But what's really confused me is the colour of the wires connected to the dimmer, one is blue and one is yellow (there is a green/yellow and a red wire to but they weren't connected, red wire also has black tape over the end). Pretty sure blue went to com and yellow went to L1 but not 100%
Sorry for the waffle... so anyway I was expecting to find a black and a red wire so now I'm stumped (I unscrewed another light switch near by and that is wired with one red and one black wire).
Is the wiring garbage (house is approx 25 years old)? Can I still change to a normal 1-way switch using the blue and yellow wire (and if so does it matter which is to comm and which to L1 as I'm not 100% sure of which way around they were before I took them out of the dimmer). Or do I need to call a sparky after all (and if so is it going to need some rewiring to sort?)
You can wire either of the two wires to comm and l1. Do that and leave the rest as you found it
Switch simply makes or breaks circuit so polarity doesn’t matter.
youre probably not in a position to diagnose if the wiring behind is safe or not, so get a spark to check or post a pic and we’ll give an opinion.
Does [url= https://www.flameport.com/electric/lighting_circuits/lighting_switchwires_twoway.cs4 ]this[/url] help at all?
Sounds like I should just use the same wires ( blue and yellow) and it doesn't matter which way around then? BTW I won't hold you liable if I blow myself up :p
@The Flying Ox - yeah I'd seen that in my googling but it confused me as it seemed to imply the blue and yellow should be used for L1 and L2 and then a red wire for the live but I just had a blue and yellow connected)
Did you put the sleeves over the wires? If not, I would assume the blue and yellow/green wires are actually on the 'live' circuit and were put there to correctly identify them.
EDIT: Not that it will help you now, but I ALWAYS photograph wiring before undoing a single thing – that way I can't forget what went where before I started fiddling.
The red sleeves were already there and yes in hindsight I should have photo'd the back of the dimmer before disconnecting.
What do the wires at the bulb end look like ?
At least whoever did it has put sleeves on.
I've not taken the bulb end apart (looks a pain with artexing on it). In the end though I just followed what goldfish said (that it's basically a simple circuit and the switch just acts as a break so the usual N/E/L stuff doesn't really apply) and wired the blue and yellow back into the new switch. Seems to all work fine now the power's back... Thanks STW 🙂
Sleeves on the wires indicate that both are line conductors, (sleeving like this is standard procedure for this)
Only issue if you put them in the switch the wrong way is the switch will operate in reverse, (down for off instead of on), if it does this just swap them round
edit: see you’ve sorted
But what’s really confused me is the colour of the wires connected to the dimmer, one is blue and one is yellow (there is a green/yellow and a red wire to but they weren’t connected, red wire also has black tape over the end).
The red, yellow, blue, earth is the old colour scheme (pre-April 2006), as is red, black, earth.
Your photo suggests that at one time it was a two-way switch, with another elsewhere (possible that it now independently switches the other light??)
If you find that switch it will have two cables with colours as above