I don't use one. I spend most of my time in the boonies using my generator for power, so I don't think there'd be an issue. Could be wrong, though.
I rarely visit campgrounds with electric hookups, though I did spend 18 months at an RV park. When the thunderstorms rolled in, I unhooked the power cord from the pedestal and ran off battery power.
2011 Dodge Ram 1500 HEMI Quad Cab
2011 Jay Flight 26BH