Frankly stated, the electrical power wiring in an RV isn't as good as home wiring, due to the fact that "insulation displacement connector" wiring is evidently allowed in RV AC power wiring. This type of connector is O.K. (but can be intermittent) in low current, voltage sensing computer and signaling connections, is used in 12 volt low power connections (ScotchLocks), but is really unreliable in high current AC power connections. Here is a illustration of an insulation displacement connection:
The electrical standard for AC power connections is the familiar stripped wire under a screw.
I have an electrical heater with a pilot light and learned about these poor connections in the trailer when I noticed the pilot light on the heater flickering when plugged into one certain outlet, and not when plugged into another outlet. A loose IDC connection in the bad outlet was the culprit.
(On edit - If you see 2 connectors in the thumbnail, ignore the one on the right)