Augie -
It sounded like I was cutting at you - not my intent. All of my questions were retorical in nature. You already know all of this.
The more I thought about this scenerio, it is not that uncommon. Generally it happens when there is a large motor load and small auxiliary load at the end of a long line. One puts in as small a transformer as will start the motors. Most then have a small panelboard on the secondary with a main and two feeders - one to the motor loads and the second to the aux loads panelboard (simplified install description). I don't recall any where a small transformer with only aux loads was just there waiting with sufficient capacity for a relatively large motor load.
If there were separate transformer taps and disconnects for the lighting and for the motor machinery, and I felt any need to keep the contractor happy, I would consider approaching the AHJ with 430.28.2 and ask for a variance. No reason not to ask unless the embarrassment factor was too high. In this particular case, there are no science, physics, safety, reilability, or operability issues - only an empty legal formality requiring the copper change. Most of the AHJs I know would accept that. But they do like to see that stamp on the request/drawings.
... No engineer involved. Building does not meet State criteria for required drawings. ...
So the EC did a design-build? And the owner didn't require stamped drawings? As an owner's agent, I have seen very few that did a good job for the owner without severe fighting with the contractor.
As a contractor, I really liked them. Lot more money.
... Never is
important to keep the contractor happy 
...
I don't often get that option. Any contractor that has the skilled people to do the job well, people don't do dope, shows up on time every day, and is still dumb enough to work in the middle of nowhere at -40, I can't afford to piss them off.
... Original post was more for "learning" in the event I encounter this situation again.
Are you a state agent for the AHJ? Or an inspector for the owner? Probably doesn't matter too much to me. I won't have any ideas on how to react from an inspector's view point. All of my ideas will be on how to not get there in the first place.
My norm is to treat remods as though they were new installations - even if I am tying into existing equipment. I really don't like cobbing on to existing equipment adding another layer of installation over the top of a myriad of others. When I cobb onto an existing system, I like it to be clean - I don't like marginal. I think maginal cuts into the reliability. Luckily for me, most of my customers, want safe, reliabile, operable. And of course, they want cost effective - but not at the detriment of all else. They find the money.
Where the majorityof the loads are 480V and one is 208V, put in a dedicated transformer just for that piece of machinery. Leave the existing lighting stuff alone. All you add with putting industrial load on the lighting is poorer lighting with extra flicker.
Nothing wrong with a dedicated xfm feeding one load. If there is enough money to make it worthwhile - ask the AHJ for the variance.
Just some thoughts
ice
