NFPA 79 has a color code system for control panels. That is a "voluntary" standard, born out of the old "JIC" wiring standards. It's what most people use though.
Green or Green / Yellow = ground conductor
White or Grey = groundED circuit conductor (aka "neutral")
Orange or Yellow = ungrounded circuit conductor that remains energized when the main disconnect is open (aka "foreign source")
White with Orange or Yellow Stripes = groundED circuit conductor that goes with the above.
Black = ungrounded line, load, and control conductors at line voltage, whatever that may be
Red = ungrounded ac control conductors at less than line voltage, i.e. 120V (if Line is <120V) or 24VAC
Blue = ungrounded dc control conductors
White with Blue stripes = grounded DC control conductors
There are lots of exceptions and acceptable alternatives, especially if identified on schematics. But even then, Green = Ground is consistent.