RW:
Glad you mentioned this very important step. Of course, for those folks who have the big Generac natural gas units, they are probably being installed by pros who handle all the gas plumbing and electrical installation, but for those using gasoline units, like myself, here at calm, for instance, this is extremely important!!
Here, my son, who is a telephone "line splicer" (so he's up on the same poles that the electrical linemen are on, and has a vested interest in safety) is installing the interface for my generator to feed into the electrical breaker box. Notice that the interface has its own breakers, four 110V, and one 220Volt. This is a limitation, considering that I have a 200 Amp service entrance, but we picked the most important circuits to run through the box, and it runs everything I need, refrigerator, TV, AC, lights, etc.
There is absolutely no way that we can energize the line running into the cabin!!! Believe me, with my son climbing poles for a living this is a primary concern for us. I also have many linemen friends, including the guy who put in the service right here at the cabin. We have a buried line through the woods for both the phone and electric. Ground mounted transformer.
We do not have to shut off the main breaker. The double pole, double throw switches are foolproof.
Once the covers are back on the breaker box, and the interface is closed up, there are no exposed connections of any kind. (Notice the rough sawn 2x4"s...cut from poplar trees that were cut down to provide space to build the cabin).
Here's all that you see on the outside of the cabin, a watertight covered plug to connect the cable from the generator to. In an outage, I can have the system up and running in a couple of minutes.
The generator is stored nearby, and secured. I only run the cable when I am running the generator, although it could be left in place permanently.
Safety for the electrical workers is really important, as you have said, they could easily be electrocuted when working on what they believe to be a dead circuit, which some homeowner has inadvertently energized.
Best Regards, Les