On a recent stay in Key West I was again thankful for my Progressive surge protector saving my trailer again. As usual I plugged it in before hooking up my camper and all showed fine. The next day after returning from sightseeing I noticed a "previous error" code showing that it had shut down for high voltage, and it did so again during the night (came back on within 5 minutes). As I was finishing coffee the next morning it shut off and I saw the voltage was reading 132v
I out my dogbone adapter and checked the 50A side and it showed 115v and after switching to it ran off the 50a outlet fine for the rest of the week.
On the last morning there I told the maintenance guy about it and watched while he checked the pedestal. He told me the had had some problems in that line of campsite in the past. The outlets were fine in the pedestal but leg 1 from power company read 115v but leg 2 at that time was 124v. The 30a outlet was connected to leg2 so obviously that one was fluctuating from the power company, while leg 1 was connected to the left side pin on the 50a outlet and my camper ran fine on it as it stayed steady.
Again was very glad to have a good product that has saved my rig on several occasions and can't imagine plugging in to any power without it.