Yes, you need to find someone familiar with electrical systems. Unless your converter is powered directly from the main breaker in the trailer (I'm pretty sure no one has ever seen this configuration), the likelihood of the converter being your problem is zero.
You could try turning off all of the circuit breakers in the rig, plugging it in and see if the problem still exists (tripping exterior source breaker). If the house breaker doesn't trip, turn on the RV's main breaker and then, individually, the other breakers until the problem trips a breaker. If the RV immediately trips a breaker in the house, you may want to look at the shore cord or in the load center for the issue.
An electrician or technician with a meter can diagnose where the problem exists very quickly. I think you're out of your depth with electrical so, again, seek help.