mr_andyj wrote:
AC wires will be grounded to the frame the same as the DC wires. As you say, probably not at the same connection point or in the same box, but AC Neutral is connected to the DC ground, and AC ground on the frame. This should not be a concern at al
Actually, in an RV, the AC neutral should not be connected to the chassis ground in any way. Connecting neutral to ground (bonding neutral) is only done at the main service entry point, and an RV when plugged into shore power is not a main service entry point--it's basically treated as a subpanel.
If there's a built-in generator, neutral and ground are bonded at the generator, and the neutral is switched along with the hot(s) through whatever means there is for power transfer--usually an automatic transfer switch or a separate socket the shore power cord gets plugged into.
If neutral and ground are connected together in an RV, that creates a ground fault, and supplying the RV power via a GFCI socket will rightly trip the GFCI. While most campgrounds don't have GFCIs for their RV outlets, there have been moves afoot to start requiring them sometime in new versions of the NEC--and personally I think that's not a bad idea at all.