Go to your circuit panel and pull that big one at the top. That is all it takes. The same applies to generators. That said, local lineman say that they don't care, because they treat every wire as though its hot and proceed accordingly. My issue is that I don't want out of phase electricity operating within my home, so I always disconnect when running the generator.
Not that you shouldn’t disconnect when running your generator, it absolutely should be disconnected, but, if it were connected, your generator would immediately sync with the grid.
Good info.