Progressive Dynamics 30 Amp Automatic Transfer Switch PD5110010QVProtect your RV's electrical system from costly damage with the Progressive Dynamics PD5110010QV 30 Amp Automatic Transfer Switch. This unit automatically senses generator power and prevents two power sources from feeding your AC distribution panel at the same time the kind of failure that fries breaker panels, damages appliances, and creates fire hazards. A small unit that prevents a very expensive problem. Why an Automatic Transfer Switch Matters