The transfer switch is suppose to take care of such a situation, but I always unplug from shore power. No need on taking a chance something might not work as planned.
But I am plugged in to a 20 amp plug at home when the coach is not being used and I can use everything in the coach except the air conditioners/heat pumps. Other then that I can use the frig, micro wave, furnace, lights, TV with no problems. I also keep the invertor on. So I do not understand what you want to use that requires that much amps, unless you want to use the air conditioner/heat pumps. Then that is a NO NO.