My Whirlpool refrigerator trips the main breaker of 40 Amps

A refrig cannot pull 40 amps in defrost , unless there is a direct short in the defrost system ( timer , heater , bimetal ) . I would use an extention cord ( for test purposes only ) , and try a different plug . Sounds like the circuit breaker is weak . In defrost , the MOST you should get , is 6 amps . This will not throw a 40 amp breaker . If you have an amp meter , remove the back refrig panel behind the refrig , and connect to one of the power cord lines (just not the green ground ) , turn into defrost and check the amps . This will tell you if short is in refrig , or weak breaker .