Anyone install an 30 amp receptacle outside for inverter?

I have done a similar thing with out motorhome, have 3 deep cycle going into the rv through a 50A circuit breaker, and off the batterys through a 150A circuit breaker to the inverter. Have put in a 40A contactor that closes when on shore power to supply power only to the interior outlets. when no shore power or generator the contactor opens, and will feed power to the interior outlets only, and not to the microwave, AC or to the charger...