ashlatz wrote:
Ok dry camper I tried what u said but the something happened
Wow. If your gen is wired normally, the breaker(s) on the gen are the last thing in the output line that sends power out of the gen to the RV. Since you've turned off the RV breaker, there should be nothing on the RV side taking any power, so the problem should be a short in the line from the gen (after the gen breaker) that runs to the main breaker on the RV. Or, it could be in the transfer switch or plug you use to connect gen to RV.
I'm not convinced this diagnosis is correct, but it's worth checking out. Inspecting the transfer switch would be next, then look at the power wiring running from the gen to the input at the RV panel. Other than that, it could be a damaged breaker on the gen, or some internal wiring fault of the gen.