My friend’s house does this with their generator. There is a lockout on the breaker, and the main must be off to move it and open the one that feeds the back porch where they tie the generator in. Once the breakers are cycled, they can plug the generator into the outlet on the porch, and it runs there, sheltered from the weather. When the main power is working again, they turn off the generator, remove the cord, disable the breaker, toggle the lockout bar, and turn the main back on. The particular outlet on the porch is useless when using grid power because of this setup.