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I'm in the process of upgrading our ceiling lights in our rather old home. The wiring of the lights in the house pre-dates 1977 and therefore the colours are slightly different which I'll list below.

Pre 1977

  • Live = Red
  • Black = Neutral
  • Earth = Green

Post 2004

  • Live = Brown
  • Blue = Neutral
  • Earth = Green/Yellow

Below is a picture of the wiring in question.

enter image description here

The diagram below for easier viewing, notice that the neutral wire of the bulb is paired with the switch (Live) and that the bulb live is paired with the neutral in and out.

enter image description here

It is my understanding, the little I have is that it should look something like this:

enter image description here

My question is...

Is this safe? is this even possible?

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6

It'll still work - a light bulb doesn't care which terminal is live and which is neutral - it's just a dumb resistor. Generally speaking however, the socket in which you put the light bulb should be designed such that the live terminal is harder to reach / harder to accidentally touch, than the neutral terminal. Since you have the ceiling rose open already, you might as well swap them to the correct configuration (your second picture).

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The "fixed" part of the wiring is correct; the wires go to the right terminals and the black wire from the switch is marked with a piece of red tape to show that it's being used for a live connection and not a neutral. The important thing is that the live supply is switched so that the lamp terminals aren't live when you need to replace it.

The two problems are that:

  • Someone has (presumably) swapped over the live and neutral to the lamp itself at some point
  • The wires to the lamp aren't passing through the strain relief points to help support the weight of the lamp fitting. They're the strange shaped bits sticking up at the sides, furthest from the middle. Passing the wires under them also helps the lamp cord hang more vertically where it exits the cover.

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