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

An issue that not many people think about when plugging in their RV that is wired for 50A service: many people "rock" the plug into the outlet rather than make sure that all 4 prongs make contact simultaneously. So, you get contact in this order: Ground, L1 and L2, and Neutral - in that order. There is a brief period of time where you will have 240V applied to the plug. Does it hurt things? Maybe - maybe not - but I prefer to err on the side of caution and switch the power OFF before I plug in...