In the end we prevailed: we made him connect the generator to the conductors leaving the distribution panel so the panel itself was cold. He originally claimed it would take half-a-day to make those connections and used that estimation as part of his justification for not doing so. In reality, it only took the sub-contractor he hired about one hour to connect up the generator.
On a related note...
Because we are still dealing with additional problems with our main and solar feeders, the primary contractor was back last Friday to have an on-site meeting with the sub-contractor and a representative from the wire distributor. Most of our facility is fenced-off with key-card access required for entry. But our main distribution panel is in a locked electrical utility room outside the fenced area; it is no more than 40 feet from our public parking lot.
Without my knowledge, he entered our utility room (he must have asked someone else here to unlock it for him) and took off the front panels of our energized 480V distribution panel. My guess is that he wanted the others who were with him to look at the installation to figure out how to replace the one defective wire out of the 8 wires in the conduit. Whatever the reason for being in there, when they finished, he not only left the panels off the live distribution panel with the bus bars fully exposed, but he left the door to the utility room wide open. Anyone could have wandered in there and gotten fried. In fact, on Monday, a group of grade school children were visiting our facility on a field trip and were milling about in our parking lot. What if they had come on Friday instead?
I discovered the open room and panel Friday evening as I was leaving, which meant that it was open for at least half the day.