In 3.0, there are only barbed-wire fences that players can take bleed damage from, and they don’t really do much other than that and aren’t really much of a deterrant to players (they can just destroy them easily) and don’t serve much other purpose than that, as there aren’t roving zombie hordes that could get onto your property, as there will be in UII.
So for that I suggest a more nerfed/endgame item similar to that, which would require a constant power source but could be used for a more functional purpose, to prevent zombie hordes from entering a fenced-off area, such as around a base. If the power was running from generators, the zombies would be zapped by the fence and couldn’t get past it.
Without the power running, zombies could get through the fence. This would have to be quite an endgame, high-tier object as it requires electricity generators, fuel, and a lot of metal.