In my first Vegas the emergency start switch as not wired correctly so it would not start the vehicle when the chassis battery was dead. It may be that your chassis battery was discharged and when you tried to use the emergency start it tripped the breaker. I would try the emergency start button and see if it happened again. You might also check to see if your chassis battery is charging while you are on shore power or generator. That has also been an issue on some Vegas/Axis.
__________________
|