Our big problem with the HVAC guys: we needed to size all the electrical feeds for their equipment, so we needed figures... watts and amps! And not to mention measures of rooftop units, for lightning protection! Try to do that with HVAC guys telling you on the phone: "Honestly, we don't have the slightest idea what's going to be installed... we just took some absolute max. dimensions and drew them into the plan you got!".
Can't say though our situation was much better... we did try to do everything right from the beginning, but until the final planning stages the architect had made so many changes the plans were hardly similar any more. In one place we went from 3 cabinets in the service room to 10 I think. I quit working in that lunatic asylum after 15 months and took up history at the university
Now I only do small house wiring for myself and close friends.
