I'm doing some work at an apartment house (upper class) built around 1960, just to find out back then people didn't stick to _any_ kind of color coding! The only consistent thing in there are the red ground wires. Everywhere else they coded the individual circuits... but they always took the same color for two circuits...
i.e. there are two circuits with yellow phase and neutral, 2 purple, but only one white and one dark blue... they stuck to that throughout the place. Mostly. I also found some wiring with black, black and red... switched phases are commonly dark blue or yellow...
