When I had my motor home I hooked up to a bad connection without any protection. Instead of 220v and 50amps this thing was wired up wrong and delivered 440v. That is 220v per line X 2! I lost: 2 TV's, microwave, sat receiver, refrigerator and 2 AC's.
After that I got a electrical management system by Progressive Industries, Inc.
www.progressiveindustries.net If there is ANYTHING wrong with the electric or the connection it will not allow electric into the RV. There is a digital readout that will tell what if anything is wrong.
Here is a list of the codes:
E0 = Normal Conditions
E1 = Reverse Polarity
E2 = Open Ground
E3 = High Voltage on Line 1
E4 = Low voltage on Line 1
E5 = High Voltage on Line 2
E6 = Low Voltage on Line 2
E7 = Low Frequency
E8 = High Frequency
E9 = Data Link Down
E10 = Replace Surge Protection
The E10 code is because if a large power surge, like lightning, hits it will burn out the surge protector. But other than that it protects the whole RV with surge protection. They have a hard wired type or a portable one. I use the portable one thank God. When I sold the motor home I kept the EMS and will use it in my new camper. I have the 50amp one and the new camper is 30amp so I'll just put on an adapter.
Terry