[JRTJH]

You can put your finger on the 30 amp breaker to feel "when it clicks". My guess is that's the one that is tripping. It will trip from being overloaded which can occur if the battery is partially discharged or if the motor is drawing too many amps for some other reason. Verify that your battery is producing at least 12.6 VDC when the trailer is not plugged into shore power. If you test the battery when plugged into shore power, you'll always get 13.6 VDC which is the output of the converter in the power center. Testing with the trailer plugged in will give you a "false good reading" at the battery terminals.