Microwave and converter fried at campground

Thanks for the feedback. I am using one of those three light testers. I keep one in the rig as a quick and convenient way to see if an outlet has power. The reversal indication was a surprise. At the time no other AC appliances were running.

I'll be checking the pedestal with my meter this morning for a more in depth assessment. I'll also look over my cord.

wnjj wrote:
You had an open neutral between the campground and your RV.

I assume you used one of those 3-light testers? All the lights do is show voltage between each of the 3 pairs of pins on a 120V recepatcle. They are literally 3 lights wired between the 3 combinations of 2 pins. If there's voltage between the pins, the light lights up. Yellow lights are between hot and neutral and between hot and ground and the red is between neutral and ground.

Normally in a working 120V recepatcle there is only voltage between hot and neutral and between hot and ground. Those are the 2 orange lights. What it calls hot-gnd reverse (one orange and a red light) is when there is power between ground and hot (orange) as well as between ground and neutral (red). It assumes the ground and hot have their wires swapped. With this assumption there is 1 hot and 2 "cold" pins.

The problem is with an open neutral on the 240V RV supply, the neutral will move closer (in voltage) to the hot leg with the most load. What the 3-light tester sees at a 120V recepatcle on that leg is power between hot and ground and also between neutral and ground...just like hot-gnd reversed, except now there are 2 hot and 1 "cold".

When the open neutral happened, half of your RV's 120V circuits dropped to nearly 0 (the half that showed the reverse) and the other half climbed to nearly 240V. The AC likely pulled the one leg way down, eventually tripping the breaker but not before frying the microwave and other things on the opposite leg.

The issue may be in the pedistal or it may be with your cord. Since unplugging and replugging in fixed it, it could be the plug, recepatcle, a wire behind the recepatcle or simply the connection between them. It may be tough to prove the park is as fault (if they even are).