I am busy installing a new light fixture however the varying colours have got me confused and google is not helping. The light fixture itself has a brown and a blue wire, however the ceiling (socket?) has a green/yellow wire, a blue, a red and a grey wire. In which way should I connect these wires? T Oh and btw, I'm located in Denmark if that helps.

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  • Are you replacing a light fixture? If so, how was the old one wired?
    – Tester101
    Nov 12, 2015 at 16:29
  • 1
    I am not replacing a fixture no. There was no fixture there previously since I have lived here so I have no idea how the previous one was wired. Refer to this link for an image of both the ceiling socket and the light fixtures wires : imgur.com/a/yAyUf
    – Victor
    Nov 12, 2015 at 16:43
  • Well, there is nothing on the images except what you've already described : ). You can unscrew the switch and post a photo of it's wiring though.
    – Agent_L
    Nov 12, 2015 at 17:27
  • What country is this in?
    – wallyk
    Nov 12, 2015 at 21:36
  • Where does the grey wire connect to from the ceiling to the new ceiling fitting Jul 2, 2018 at 13:32

1 Answer 1


Most likely you connect blue to blue, and brown to red or brown.

BUT you should really test it with voltage and continuity tester to be 100% sure you're connecting outside thread of a bulb to neutral and the pin to live.

How I understand colours of your wiring at the ceiling:

  1. green/yellow: ground
  2. blue: neutral
  3. red: circut 1 live
  4. brown: circuit 2 live

I assumed you have 2 switches on the wall. If you have just one switch, then possibly one of the live wires is not connected at all OR the opposite: it's permanently connected (for remote-controlled lamps).

And wiring on the fixture:

  1. blue: bulb thread (must be connected to neutral)
  2. brown: bulb base (must be connected to live)
  3. metal thingy - if your fixture has extra screw that's simply connected to the metal body of the lamp, this is where the yellow-green ground wire goes)

About the testing you should do: With a neon probe on the wires coming from the ceiling: turn both switches "on" and verify which wires are live. Turn the switches off (or even better, ask someone to keep cycling one of them) to verify if they switch off properly and which switch is which circuit. With a continuity tester (eg. ohmmeter or a buzzer) on a disconnected fixture: check if blue goes to thread and if brown goes to base. Sometimes you can disassemble the fixture a tiny bit to simply see where the wires go.

  • Hey thanks for the fast response. I understand that I should probably run the tests you mentioned but I really do not have the money to invest in the equipment. Also, regarding your assumption, I only have one switch so I guess that it IS permanently connected. What is the worse that could happen besides tripping the power if I tried a bit of trial and error ? Also, here is a link of the images for the ceiling socket as well as the light fixture wires : imgur.com/a/yAyUf
    – Victor
    Nov 12, 2015 at 16:48
  • @Victor Not much really. If the light seems to work (without tripping the RCCB) there are only 2 possibilities: you either wired it right or the wires are swapped: live is on bulb thread - which means that replacing the bulb with lights on is more dangerous.
    – Agent_L
    Nov 12, 2015 at 17:21
  • @Victor Oooh, I forgot one thing: if your fixture is built-in non-removable leds or electronic ballast fluorescent then it's almost negligible if you swap live with neutral.
    – Agent_L
    Nov 12, 2015 at 17:23
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    I just wired it the way you recommended (Blue to blue and brown to red) and it seems to be working fine. Thanks a bunch!
    – Victor
    Nov 12, 2015 at 17:37
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    @Victor One more thing about equipment: a neon probe should cost about 1€, and it's super-handy every time you fix home wiring. Plus it doubles as screwdriver. A multimeter is bit more expensive, but a 5€ one is enough for home use.
    – Agent_L
    Nov 12, 2015 at 17:39

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