My Progressive EMS has shut off my power due to low voltage several times in campgrounds. The most recent shut off was at my home base site which is in a residential area plugged directly into utility power. This was a high voltage shut off and happened two mornings in a row at 3:00am. This turned out to be a bad utility transformer which they replaced. A couple of times it shut me off in a campground due to lost ground.
One big advantage of the unit other than the above is if you are running your a/c's and have a shut off or even a temporary power outage the unit won't turn your power back on for 2 1/2 minutes to protect your a/c compressors.