Had professionals install two 12/120/3000 Multiplus’ in parallel. All worked for a week and then randomly main shore power in breaker tripped and continues to trip instantly if shore power is connected. Contractors said it was the type of Shorepower in breaker and that it didn’t “filter” some noise that caused Multiplus to trip. They installed $500 of new main shore power in breaker/panel/box. Everything worked great, again, only for a week. Now Main Shorepower in breaker continuously trips if Shorepower and Multi’s are both connected. At least the new breaker/panel has an indicator that shows leakage fault when it trips. I have an emergency switch I can turn that disconnects Shore and Multi’s so I can stay connected to shore power. But need to try and figure this out without contractors as they have lost my confidence. Puzzling part is why everything worked fine for a week then stopped both times. Any thoughts?