Originally posted by: oneye
The quoted Spec is a little vague, generally the end user specification dictates wire colours to be consistent with other panels on their site.
24Vdc tends to be red/black, 24Vac could be light blue / dark blue but that can easily confuse 110Vac brown/blue.
Some have 24Vac orange/orange whereas other clients have orange/orange to be voltfree non isolated external supply @ any voltage.
You need to nail down what colours are acceptable before you start.
All panels I have worked on previously had the ac/dc colours opposite to the quote above.
Whilst I agree the spec is vague & BS EN 60204-1:2006 is the standard to work too. See paragraph 13.2.4. Red = ac control circuits at any voltage. Black = ac & dc POWER circuits at any voltage. Blue = dc control circuits at any voltage. Orange = excepted circuits according to para 5.3.5. White tends to be functional earths, taken from BS7671.
There is a few colours that you can use, but as per previous post, get customer specs, or at least written agreement.
You can't use, yellow, green or green/yellow if it may be confused!
I have only seen orange "live with main isolator off" that is fed from another source.
Not seen brown in a control panel except incoming (new colours) and in special multicore cables, signal wiring etc.
There are other relevant standards as well depending on the equipment.