You need the circuit breaker turned on for each cord you have plug in.Not sure if you can help me on this, but the box has a 20, 30 and 50 witch on it. Right now I have 20 and 30 turned on, not sure if I need the 30 on is all
If your RV has a 30amp cord, you need the 30amp breaker turned on. If your RV has a 50amp cord, you need the 50amp breaker turned. If you plug something into the 20amp receptacle, then you need the 20amp breaker turned on.
If nothing is plugged in, then all the breakers should be off.