(E)400A-1P service. Office bldg being "mostly gutted". (E) and (N) lighting and rcpts to be added to 2 new panels. 2 (E)panels to remain have HVAC & misc. Do I treat this as "new" or "addition"? Any guidance is so appreciated!
I would assume that you mean for load calculations. I would then treat this as new (especially since any load history is probably meaningless due to the major changes and perhaps new occupant) and the connected load should not exceed the supply unless you can show that certain equipment will not operate at the same time.
In similar situations I have always treated them as new.
I have always talked to the AHJ and asked them what they wanted.
They have always wanted it treated as new and it made sense to me.
Call the electrical section of the building department in the location of the job. Talk to the chief electrical inspector. Ultimately that's where your answer will come from, better to find out now as later.
I spoke with the AHJ to confirm the requirements. I was trying to figure out if I needed to use NEC 220-35 to look at existing vs new loads. I decided not to go this route since the existing to remain are so few. I am just showing all the loads and doing load calcs for everything. thanks, everyone!