1) It wasnt mentioned that when the circuit trips whethor or not the
frig then loses power too, or not. Does it lose power too?

2) I agree with above that you should put the frig under its own
dedicated line and breaker. Is this an old frig? May be time to get a
new one?

3) The contacts in the frig, from the actuator or relay, could be dirty
and need replacing. If they are this could cause sparking and a
feedback surge being felt on the other circuit. If I am hearing all
this correctly, the frig is most likely your problem, not the lines.

Dean