Bill, Eric and Kent,  thanks for all the suggestions.  No new refrigerator gas has been added since I have owned the boat (three years).  I agree with you that something is causing the rear unit to draw more than 10 amps.  I think I will pull the unit next and see if there is something that correlates with the circuit breaker tripping.  If I do not see something obvious, it will be time to call the Climma technician!