The Xantrex switch is used to provide AC power either from shore power (if plugged in) or from inverter. If plugged in to shore power, all AC power in van comes from shore (so as to not pull from inverter, and therefore house batteries). If not plugged in to shore power, AC power is from inverter. It senses the incoming source and does this (switches) automatically which is very nice!
The 30A fuse on solar input seems excessive. I have 2 - 100w panels and am using a 20A inline fuse. The most I have seen from solar so far is around 8 amps (although I haven't had the house batteries drawn down too much since my solar was installed).
I would probably go with a breaker between the CCP and battery switch..or have the fuse easily accessible to be able to change if needed.
