P
Paul_C
Do you find it confusing that some MCBs show red when ON and green when OFF.
That subject can spark quite a debate itself when it comes to annunciators, with some industries preferring red for on (danger) and green for off (safe) and others using just the opposite (green for go, red for stop).
In the USA the phase is black and the neutral white. Both in fixed wiring and equipment leads
And additional phases are normally red and blue, although for the last 40 years or thereabouts the N.E.C. has not stipulated mandatory phase colors, so anything other than white, gray, and green can be used. Where multiple voltages are in use in the same installation, it's common practice to use different colors to distinguish between the two systems, e.g. black, red, blue and white neutral for 120/208V and brown, orange, yellow plus gray neutral for 277/480V.
In the Clifton area of Bristol the phase colours are red, blue, green and a white neutral.
I assume you're talking about outside distribution plant? Was this a smaller independent company which didn't get absorbed into the "big" electricity board until rather later, hence the retention of its scheme?
When 3 core was R, Y and B and I wanted to use one core as neutral, I would use blue.
This was mainly because just about everyone else did.
Such use - without reidentifying as black - was sanctioned in certain circumstances under the I.E.E. 13th edition, prior to the 1964 changes.