My house panel serving the house and farm outbuildings is "plugged in" permanently via a #6-3 cable running from a normally OFF 240V (emergency) breaker in the panel box. The cable is appropriate length, going outside and fitted with a male plug compatible with the generator. The plug resides in a protected location and is terminated by a female plug to cover the male prongs. Emergency power activation is to throw and lock the main breaker OFF, then remove the cable termination outside and plug the male into the gen. Start the gen, then go back inside and flip the emergency breaker ON. All selected ON breakers in the panel are now powered.