Will they let you only bring single phase into the building like you want? If the panels and distribution that's in there now is 3 phase it'll need to be replaced with single phase and that's probably something they would want to see done by an electrician. You might be better off getting an electrician to trace whatever you want at the same time. It does't take them that long and even if they label stuff and you can remove what you don't want yourself the time saved would probably be worth it.