wiring a 30 Amp Power Outlet 30A Circuit Breaker {{UPDATE}}

Damage/arcing done by plugging in with breaker on or off is HIGHLY dependent on load.

If you have both A/C's on you WILL have some arcing that will pit the prongs of the shore power cord and also the receptacle.

And, this also applies to switching from shore power to generator. Best done with little or no load. Then breaker/switch a LOT less important.