Dual pole ITE circuit breakers do what their single pole counterparts can't; they allow appliances like washing machines and refrigerators to operate with their higher energy demands without causing an overload. Dual pole ITE circuit breakers are able to do this thanks to their construction. Single pole ITE breakers are used with 220-volt circuits. They have two "hot" or live wires, as opposed to the 120-volt circuit's single wire.
If either one of the 220-volt wires has a short, the dual pole ITE circuit breaker is built to trip and kill the power completely. If an air conditioner were wired to a pair of single pole ITE circuit breakers it could trip one circuit while leaving the other active. This would create a serious hazard. The use of dual pole ITE circuit breakers avoids that hazard completely.