Why one service drop?

[tom baker]

Alright, the issue and rule is Fire Department driven and eventually applied; thanks.

The second part of my questioning was not answered. What about multiple emergency generators? Is there no problem with this, multiple transfer-switches, and different circuit panels from the generators? What does the FD says about this?

There are rules in Art 700, 701 and 702 on labeling of sources of power. Keep in mind generators are typically feeders and there are also rules on feeder disconnects from generators, see Art 215 and 225/