I've looked at similar questions and answers and they don't make too much sense, I guess because my wiring may be different to others.

#80208 and #36266

So I thought I'd replaced like for like with the wiring from the previous light fitting to the new, but now I have a light which won't switch off.

Please can someone help with this wiring picture to solve the issue for me.

enter image description here


This is one side of a lounge/diner and the exact setup is in the dining room, dimmer, with a newly replaced light (from the same, to the same), here's a shot of the side that does work: enter image description here

  • Welcome to DIY.SE! Can you explain what we're seeing in your picture? Which wires are hot, which are switched hot, which are neutral? What type of fixture is it? And, where in the world are you?
    – mmathis
    Commented Nov 15, 2016 at 22:26

1 Answer 1


From the color of the wires I assume you are in either Australia, New Zealand or the UK if the home was built prior to 2004 which it certainly looks to be.

The red and black wires are your hot and neutral lines respectively. Since there is a big junction of three sets, I am guessing they are feeders and are always live. Your light is connected across them which is why it remains on. That being said, what is that blue wire doing by itself?

It looks like the lonely blue wire is paired with the brown wire. They look like they form whats called a switch loop. The brown wire is the feed to the switch from the red hot wires. The power is then fed back via the blue wire.

If you have a voltage tester, turn the switch on and test from the single blue wire to the black leads. If it shows power, turn the switch off and repeat the test. If you don't have power, you found the switch leg which is the blue wire. You then move the brown wire of the cable going to the lamp to that lonely blue wire on the terminal strip.

If you don't have a voltage tester, don't worry. Just move the brown lamp wire to that blue wire and turn your switch on and off. Even if its the wrong wire, nothing should blow up.

Edit: added a picture for clarityMove wires

  • Thanks for your explanation and how to potentially fix... I say potentially, because it doesn't seem to have resolved the issue. The light doesn't turn on of off after moving that upward brown to the lonely blue. I have tried the switch on/off a couple of times. (It's on a dimmer switch, I assume this doesn't make a difference).
    – Phil
    Commented Nov 16, 2016 at 10:52
  • If this wiring was existing and it worked before, then we still have to look at some potential issues. I know this sounds silly, but check the bulb or try another bulb or two. I once wrote off a lamp because a working bulb failed and fooled me into thinking the lamp was bad. Check the dimmer. Is it actually on? And finally, pull the dimmer and see if it actually hooks to those blue and brown wires.
    – Mister Tea
    Commented Nov 16, 2016 at 12:55
  • I left the wiring as you said and then checked and double checked everything but the switch as I can't get it off the wall! However, 10 minutes before I switched from the chandelier to this new fitting, (which had three wires, L, N and Earth) it worked fine.
    – Phil
    Commented Nov 16, 2016 at 16:15
  • Updated with Diner light setup above now
    – Phil
    Commented Nov 16, 2016 at 19:43
  • Your diner light setup has a switch loop as well. That one cable of the left in the ceiling which connects to the fixtures brown wire has red tape on the black line. That is standard electrician practice to mark the wire as a hot return wire from the switch. That cable is your switch loop. Now this has me thinking, did you change any of the wiring on the original setup? As in, did you remove any tape from a black wire OR group the red and black wires which weren't previously grouped?
    – Mister Tea
    Commented Nov 17, 2016 at 14:05

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