The ballast in one of our oldest florescent lights finally died, so I thought it would be a good opportunity to replace it.

The wiring was a bit of a jumble (I should have taken a photograph).

We have a main light, with 2 switches (upstairs and downstairs), then next to that, a second smaller light with a separate switch to operate that independently, which looks like it is wired to the main first light. But I'm not sure how to attach it.

I understand the 3 red wires all go together, and the three black? But where do the 3rd set of black and red go? :( ...I'm guessing they might be for the second light/switch?

The picture below is of the wires which were attached to the main light, and below that is the connections to the new florescent light.

(1x light + 2x Switches) + (1x Light + 1x Switch)

  • 2
    Is this in Europe? The color codes don't match conventional North America standards.
    – wallyk
    Sep 7, 2014 at 16:31
  • United Kingdom, Sorry :) Red (old style)/Brown = Live & Black (old style)/Blue = Neutral
    – Relievo
    Sep 7, 2014 at 21:29
  • 1
    I'd really like to know how those were attached to the previous fixture(s)...
    – keshlam
    Sep 7, 2014 at 23:01
  • The thing that really confuses me is the pair where red and black are spliced. That might barely make sense in the US conventions, where red in a three-conductor-plus-ground cable may be used as the "alternate hot" (second switch in a pair, second traveller, etc.) Given what we've been told is the UK convention, this is Just Plain Wrong... I can almost invent a scenario involving a switch stub, but I can't convince myself of it.
    – keshlam
    Sep 8, 2014 at 12:45
  • (I'm also a bit surprised/confused that the second light claims to have a ground connection when the first light doesn't.)
    – keshlam
    Sep 8, 2014 at 12:46

1 Answer 1


You need to connect the switched live to the brown wire in the new fitting and the neutral to the blue wire. The neutral will be one of the black wires. The switched live may be red, or it might be a black wire in one for the T&E cables (though it should have red tape or sleeving on it if it is...).

You might need look at the switches to try and figure out which cable is which. A typical arrangement for two-way switching is shown here (I've linked rather than inline-display the image for copyright reasons).

I'd hazard a guess that the two cables with the red and black joined are the feed coming in and going out to the next fitting on the circuit - but don't take my word for that, please check that for yourself.

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