Avoiding an open neutral connection is a crapshoot, and all you can do (unless you never use 50 amp power) is make the odds a little better in your favor. Each electrical connection point is a possible point of failure. From the RV park pedestal outlet female contacts, to your shorepower cord mating male connector and wiring clamp screws, to the RV inlet connector wiring clamp screws, to the 50 amp RV inlet female connector, to the RV side 50 amp male connector and its wiring clamp screws, to any transfer switch and/or EMS wiring clamp screws and power pass relay contacts, to the wiring clamp screws on the inlet wiring on your AC breaker panel. Remove the female/male inlet connection points form the list if you have the cable reel, and insert the connection points for the cable reel. A good electrical designer minimizes these possible points of failure. The good/bad news is that over the years most of the reports of this problem have been due to campground pedestal wiring/loose screws. I think that the disturbing news is that as time progresses the campground pedestal problems are lessening. and we are hearing more of RV wiring problems causing this.
All you can do is make sure ALL connection wiring screws are tight on a regular (yearly?) basis. I don't know how to access the 50 amp female connector on my trailer's side, so I haven't done this one (yet). I also use Cramolyn contact cleaner/restorer spray on the park pedestal outlet, my shore cable ends and shore cable input recepticle. Both my transfer switch and EMS power pass through relay contacts have been treated with Cramolyn. I turn off my inside AC main breakers BEFORE disconnecting or connecting shore power to eliminate contact arcing on the EMS/transfer switch power pass-thru relays. 50 amp power is the exception to the rule at the Thousand Trails Preserves I fulltime at.
The big thing all RVers can do to minimize campground electrical problems for everyone is: ALWAYS TURN OFF THE CAMPGROUND PEDESTAL CIRCUIT BREAKER BEFORE CONNECTING/DISCONNECTING YOUR SHORE POWER CORD TO THE PEDESTAL OUTLET. Having the pedestal breaker ON when connecting/disconnecting your shore power plug, causes an arc burn in both the female outlet and your male plug blades. The arc burns and oxidation processes from air and heat at the connection point promotes a deteriorating electrical connection condition that eventually causes problems.
