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I've got the three separate ceiling lights all on the same switch. The other two are simple with a single grey cable fitting. But this one is obviously the key light because it has three main grey cables.

When I wire up this one up according to the diagrams available online I find I can't switch the lights off.

I've used this diagram as a guide, though there are many similar. It fits my setup/wiring/colours almost exactly (except in my case the original installer has taped one of my blue wires (which I understand to be my "switched live") red instead of brown as in the diagram. I presume that's an entirely cosmetic difference.

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So, retracing my steps I detach all the light fitting paraphernalia and just try it with the three brown/live wires bound together (as should be standard according to the diagram) and still its sister lights (on the same switch) won't turn off. To kill the light I actually have to disentangle the three brown/live wires.

enter image description here

What am I doing wrong?

I guess this question looks much like this one, but the best answer has the same diagram I feel I have worked from (except different colour scheme).

Edit
Per Tester's answer, and if the diagram is wrong do I need to move one of the browns over?

enter image description here

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2 Answers 2

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One of the brown wires will bring power to this point, another will go to the switch, and the final brown wire continues on to the next light. The markered blue wire brings power back from the switch, when the switch is in the ON position.

You need to connect the brown that has constant power, to the brown that goes to the switch. Next connect the markered blue to the light, and to the brown wire that leads to the other lights on the circuit.

The green/yellow, and blue wires in your image are connected properly.

As you currently have it wired, you have the wire that feeds the other lights connected to constant power. So they will always be on.

Locating the hot

WARNING:

This procedure should only be carried out by persons with the proper tools and knowledge. And should be carried out with extreme caution.

  1. Turn off the power to the circuit at the breaker/fuse box.
  2. Disconnect all brown wires, and position them so that they are not, and will not come into contact with any other wire or metal object.
  3. Turn the power back on at the breaker.
  4. Using a multi-/voltage meter, touch one probe to the "neutral" wire block (where the blue neutral wires are connected).
  5. Touch the other probe to each brown wire in turn.
  6. If you get a voltage reading, mark that wire in some way.
  7. Turn the power back off at the breaker/fuse box.

You should have gotten a voltage reading on only one of the brown wires.

WARNING:

If you got a voltage reading on more than one wire, STOP, do not follow the rest of these instructions. contact a local Electrician.

Now that you know which wire is the power wire, it's time to locate the switch wire.

Locating the switch wire

  1. Find the blue wire that is marked as a switched hot wire.
  2. Follow the wire back to where it exits the cable sheath.
  3. Mark the brown wire that comes from the same cable sheath.

The brown wire that is part of the same cable as the marked wire is the switch wire.

Making the connections

  1. Connect the brown hot wire to the brown switch wire.
  2. Connect the blue markered wire to the remaining brown wire, and to the light.
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  • thanks what you say makes sense, i think. but does that mean my first diagram is wrong? cos that has all three browns joined.
    – hawbsl
    Nov 18, 2013 at 14:34
  • Yes. Your diagram and wiring are wrong, that's why it's not working properly.
    – Tester101
    Nov 18, 2013 at 14:52
  • how do i know which is the "brown that has constant power", which is the "brown that goes to the switch" and which is the "brown that leads to the other lights"?
    – hawbsl
    Nov 18, 2013 at 15:18
  • perhaps you could look at my edit, thanks very much
    – hawbsl
    Nov 18, 2013 at 15:41
  • 2
    A non-contact voltage sensor would help you.
    – Bryce
    Nov 18, 2013 at 20:46
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You're connecting it wrong

There are two ways to connect those UK 2-3-3 connection blocks with a switch. #1 controlling this lamp and also downstream lamps from this switch. #2 controlling this lamp only and feeding always-on power to other outlets downstream.

All your diagrams are for #2. You need to use the diagram for #1.

My answer here describes both cases. The neutrals stay put, you swap some other wires. I couldn't find a pretty diagram for your case, everyone who draws these diagrams seems to draw them for the other case.

If you don't know which is supply and which is downstream, take a guess - if it's wrong, this light will refuse to turn off.

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