I am trying to fit a new light fitting. The connections on this fitting equates to a 4 pin plastic junction box with live, earth, and neutral in that order with the 4th blank.

I removed the old ceiling rose but forgot to take a picture. Nightmare. I am left with 3 red wires, 2 black wires, and 3 earth wires. I cannot tell which cable is the switcher cable because none of the wires have insulation tape on them.

So far I have not wired directly into the junction box.

I have used the old ceiling rose and wired a neutral cable from the fitting directly into the left hand pin on the neutral. I picked one of the 2 black wires and wired that next to the fittings neutral.

I then wired the 3 reds into the 3 centre connections. Finally I wired the 2nd back into the left hand side of the 2 hole junction and finally the live cable from the plastic junction box of the fitting into the right hand side of the 2 hole junction.

All 3 earths then wired into earth terminal.

Power back on and nothing.

I swapped around the 2 black wires and power back on.

Light fitting bulbs on but very dim and no control with the switches. This is as far as I have got because I really don't want to be guessing and I really thought one of the black wire would be the switcher.

  • Hello, and welcome to Home Improvement. It's hard to understand what you're talking about; would you add a picture or diagram (or two) to help us? Jan 20, 2019 at 14:11
  • I edited this to fit SE's markup style, where you must use a double newline for a new paragraph. Single return does nothing and makes your post run-on into one monster paragraph. Also to try to clean up use of "wire" and "cable", people confuse them all the time, a cable is several wires inside a sheath. Jan 20, 2019 at 20:29

1 Answer 1


Sussed It

From trial and error located live switch. It was one of the 3 all red cables.

This wire went into live wire junction from fitting

Next was 3 earths into earth for light fitting

Next was the 2 black neutrals into neutral from fitting.

Finally left with 2 red cables and they went into the 4th hole on the junction box on there own.

Power on... Light fitting working with correct brightness and upstairs and downstairs switch both working to turn light on and off.

Only took me 3 days on and off.

  • 1
    While I am happy it worked, I must caution. Trial-and-error is dangerous, because many combinations will function but are unsafe. It's only safe if you know why it worked. Jan 20, 2019 at 20:31

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