There are many factors that will determine the size transfer switch needed (size of utility service, appliances needed to run, size of generator, etc.). The transfer switches vary in size from 50, 100 and 200 amps. Fill out our contact us form, and a customer service representative will respond promptly to your inquiry. The 50 amp transfer switch has a sub panel in it capable of connecting to eight circuits. The 100 and 200 amp transfer switches are whole house feed and feed the entire distribution panel.