Shortly after we bought our 5th wheel we had an open neutral in the power cord and it fried several things in the trailer. We had a Surge Gard plugged into the pedestal but since the issue was after it, it didn't protect the trailer.
After a lot of searching we installed a Progressive 50C unit and love it. It's been there for a couple of years and it has caught both low and high voltage for us.
One thing I did discover was when we used our generator it threw a code I called Progressive and they had a fix for it . They call it a Gen-Plug it ties the ground and neutral together if I remember correctly.
2013 Newmar Dutch Star 4318
2019 F150 KR