The electric potential of the ground is taken to be zero. We will get electric shock if we complete the circuit by touching the wire and standing on the ground simutaneously.(I know the shoes cannot protect us as the resistance is too small) But what does this "ground" really mean? Does it apply to any floors we are standing,even those on high rise buildings/those do not contain any electric wires and completely made of thick,insulating material(like plastic)? I was wondering if there are any grounds where people standing on will never get electric shock(the lethal one)?