If you are referring to labeling all the wiring in the cabinet according to the electrical schematics, it may not be a written standard, but I think you be crazy if you didn't label EVERY wire and jumper.
I worked for a European Robot maker that did not mark any cables or wires.All of the wires were color coded and few cables were marked. They sell robots all over the world that are marked like that. I am sure the the robots were CE rated.
I've worked on German panels and found their control wiring to be all one colour. The schematics showed where the wires landed and the exact terminal numbers...no wire markers!