my back up power was done a slightly different way.
an electrical buddy was having his car rebuilt in my shop, he is next to hopeless working on a car, but a genius for pulling wire.
i have a 6500 watt genset that puts out 24 amps so thats where my buddy started.
he brought over some teckie test equipment to see what the needed appliances pulled for amps when they started up.
his goal was to not exceed 20 amps.
in very short order he came up with a list of what i could power up with the generator
220 volt deep water pump, the fridge, the furnace, 6 60 watt lights, and a large coffee maker!
he put in a small sub panel in the house with all the needed stuff in it, then ran some heavy guage wiring , i believe he called it cab tar? outside in has a odd plug in (4) prong that locks into the genset. at the other end where the sub panel is he used the same wire. heres the neat part...the sub panel unplugs from the main panel
with the the same twist lock plug then the genset plugs into the sub panel! he made sure that by wiring the sub panels female plug that the power supply could not be plugged into the main panel. works very well no issues.
as an added precaution he also made me purchase a couple of good quality surge protectors, in case of power surges\drops lightning, put those on the well,fridge &
computer(45.00 bucks a piece but well worth it!)
have used this system quite a few times,being out in the country, even the wife can switch over to back up power,