The guys I have watched use some strict color coding to indicate what is going on in a box. Red, black and blue is 3p wye, 120v to ground with a white neutral. BOY is 480 L/L loads and 277 L/N loads are violet with a grey neutral. They used BOY tape to further identify violet conductors.
That may have just been a local convention but a quick peek in a box and you knew what you had going on. They also wrote the panel and breaker number on each box when they built the system.
These were state projects where the guy building it was also going to have to live with it so they spent the extra time on the front end to make life easier down the road.
