So, I was around my partners house the other day and they have a light on the landing that does not work - I don't think it has ever worked since they moved into the house and being an electronic engineer I assumed it would be an easy fix so I tried to have a look at it and hence fix it but I could not for the life of me figure out what the problem is. I have taken a few photos and with those and information I provide I hope someone will be able to help me out with this but I won't hold my breath as two electricians have had a look and both have failed.

Anyway, the attention from the electricians was focused on the light itself so I decided I would check out the light switch instead - it is a two gang switch and the other light that is attached to it works fine but I couldn't see anything obviously wrong and I looked at the light itself as well and still not luck with that side of things.
Below are a couple of images of the light switch innards which might help shed some light on the situation for some people:
enter image description here enter image description here So I think my main problem that I had is that I didn't actually know which colours were which and what they did but this is what I assumed after researching but really have no idea:

Red - Live
Blue - Neutral
Yellow - Earth
Black - Three-phase: L2

It might be worth mentioning that I live in the UK so it is a UK wiring system - not sure how old the house is hence my confusion when trying to work out what each colour means.

The light that isn't working is connected to the L2 side (the bottom of both images) and the only difference I can notice is that it doesn't have a black lead going into it... I am no expert and have only wired a light switch once (didn't exactly go very well but that's a whole other story) so don't really know if there is anything wrong with these images at all so to cover all bases I have also taken pictures of the light and how that is wired up (I apologise in advance for the low quality of the pictures):

enter image description here enter image description here

If anyone can identify a problem with either sides then please share your insight as it is quite annoying that it doesn't work.
If there is any more information that anyone needs, leave a comment and I will do my best to obtain it - including better images of other things if need be!

Oh I just remembered that there is a second switch for this light which I have an image for below:
enter image description here

Blue and black are for L1 and red is L2, yellow is common.

  • Have you confirmed that the switches are function? Do you know if power is getting to the lamp? I'd take a multimeter to all the connection points, and check for voltage across the leads. Start at the switch, and confirm that it works, and then check the lamp.
    – Nick2253
    Feb 19, 2015 at 16:27
  • Are you sure there isn't a third switch, like the second one? Looks like each light is controlled by two switches ("staircase" style wiring)
    – Dan
    Feb 20, 2015 at 7:10
  • @Dan I don't think so, there is a second switch for the other light downstairs but I think it's just the two for the one that isn't working
    – MrPhooky
    Feb 20, 2015 at 7:14
  • So you have two staircase type circuits, one for each lamp. Each circuit uses a simple switch and a half of the double switch. Correct so far?
    – Dan
    Feb 20, 2015 at 7:16
  • @Dan well the one that isn't working, both switches are upstairs like a doorway apart (a bit excessive imo) and the one that does work has its second downstairs as part of a 3gang switch but yeah pretty much
    – MrPhooky
    Feb 20, 2015 at 7:18


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