The hitch ball is a movable link between the TV and camper. Lightly grease to prevent wear as as greasing the movable parts in your vehicle. A light coat of grease will have zero impact on an electrical ground feature. Remember your tow chains, breakaway switch cable and EQ hitch bars/chains also provide a path for a ground.
2012 Fun Finder XT 276 Toy Hauler & Harley Davidson Ultra Classic with Condor wheel chock
2014 Dodge Ram 2500 AT 4X4 Crew Cab 6.4 L Hemi, 373 gears, tow package, Rambox option, Revolver X2 tonneau cover, Equal-I-zer anti-sway hitch.