A 7KW/ 14 KWh multimode system has been installed at a residence, ac-couple with the customer’s existing 6.7kwh ac PV system. The system providers uninterrupted power to a protect loads subpanel, which is connected to a refrigerator,

Microwave, 1.0 ton are conditioner, three lightning circuit, and the 6.7kwac PV system. One month later, the homeowner moves additional circuits to the protected loads subpanel, substantially increasing the loads. Why would this cause, the backfed interconnection breaker in the main service panel to trip?