The on/off switch on the wall is what most call the salesman switch and it usually just turns off all the 12 volt. to keep the house batt from going dead while sitting on the lot. Turn on a light and turn the switch off and if the light goes out that's it.
Is it the same breaker that trips all the time??? If so check what is on that breaker, it could be the converter or A/C unit, etc. that is causing the problem. Then turn off each item on the circuit and see if that stops the problem if it does you've found the problem.
Another thing to do when all power is off and RV unplugged from ground power is make sure all the wires under all the screw connections in the breaker and fuse box are tight.
Are you sure your not overloading the system running to much at one time?