Where did you get the idea that only one leg of the breaker will trip the current if an overload. That means that that one wire must short or overload and only that one. great, which one will it be. The other one is free to deliver all the current it can up to the point the main (100 amp) trips. I dont think so. $7.49 for a single pole at HD last week. I would just use one or the other phase and not worry about blankers or buying a new breaker. PLEASE check outlet for proper voltage before plugging in camper. TOO many postings on people hooking up to 240 volts by mistake.