Here's a photo of wires coming out of my ceiling (grey, yellow/green and black) and the wires going into a ceiling lamp (brown and blue).

So in Australia the general colouring codes go like this:

Brown: Active / hot
Blue: Neutral
Green/Yellow: Earth (ground)

I didn't do the wiring in the picture, it was there when I bought the house, but when putting up new lights I want to make sure it's done right.

Obviously this is a sloppy job with the ground wire missing!

My question is: The grey and black coming out of the ceiling, which is active/hot and which is neutral?

For obvious reasons I don't want to invert the phase by switching around hot and neutral.

enter image description here

  • If the light is double insulated, not earthing it is not only not bad practice, it is mandatory. You are breaking code by earthing it. Commented May 5, 2017 at 10:10
  • It seems the light is not insulated. So earth is required then?
    – ChrisRich
    Commented May 6, 2017 at 13:30
  • Look on the light's nameplate. Does it have the double insulated symbol (a box within another box)? If it does, it cannot be earthed. If it doesn't, it must be earthed. Commented May 8, 2017 at 5:20

3 Answers 3


So after a little research I found out that there's a colour code for older installations:

Black: Neutral
Grey: Active / hot
Yellow / green: Ground (earth)

And for modern wiring:

The active wire (high potential) is coloured brown (used to be red).
The neutral wire (low potential) is coloured blue (used to be black).
The earth wire is striped green and yellow (used to be only green).

  • Do you have a source on this? That white cable looks quite new (especially given the earth); I don't think it's very old work. I suspect this is either run in conduit (white is Phase #2 in standard Aus/NZ colours) from e.g. a sensor, or it's a US fitting. Commented May 5, 2017 at 10:07
  • Red-Black-G/Y is still standard for fixed installations, though Euro colours are acceptable. It's only flex where Euro colours are really the majority. Any bulk cable you buy will still be Red-Black-G/Y. Commented May 5, 2017 at 10:08

Use a multimeter. It's almost certain the green/yellow is ground. Which ever wire gives you voltage to ground is hot. The one that gives zero volts to ground is neutral.


Confused me for a moment, as US uses the opposite, but black here in Oz is Neutral in the wall, so connects to light blue in the device. White in this case is the SWITCHED active, where red (active) does down to the switch, and white comes back. It goes to the brown. Blue can also be used as a phase, in which case the colours are red, white (or yellow in old systems), and blue (often darker).

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