New generator checklist:
1) buy appropriate generator
2) buy interlock safety switch
3) hire licensed electrician to install above.
A pilot, doesn't get to pick and choose which checklists he or she agrees with. I mean seriously, you wouldn't take off without, say, flaps installed for example, right? Every piece of hardware that is required by the FAA or other authority having jurisdiction is there for a reason. Generally arising from the hard lessons of past experience. Yes, you might get away with it -- until you don't. In this case, the AHJ has specified the installation must conform to the rules set out in the NECC. There's your checklist.
Back to the original subject: failed diesel installations can burn down the house (or barn, or whatever). Failed gas installations can blow up the neighbourhood. I've been to a few of those, both NG and LPG fueled including the
Etobicoke Mall and
Sunrise Propane.
Come to think of it, both of those resulted from failing to follow proscribed regulations.