Shore Power and 12v power

[Sands Riddle]

Can both panels be powered up at the same time?

 

[Richard19068]

Sure. Should be no problem.

Do you know Erskine Childers' books?

 

[Davidasailor26]

Yes, and they usually are. I assume you mean just being plugged into shore power, using some 12V and some 120V appliances, not talking about using an inverter to feed the 120V side. If using an inverted, the inverter should only ever power the house AC circuit if the shore power side is disconnected or switched off.