Aerial Bunched Cables (Aerial Bundled Cable or simply ABC) are Overhead Power(cable aereo electrico) Lines. Usually, in this cable several insulated phase conductor are bundled together tightly with a bare neutral conductor.
This thing makes a slight difference between normal uninsulated conductor, which have an air gap, and ABC. In Air Bunched Cable, type of overhead transmission, the principle is same as of bundled conductor. In Air Bunched Cable, these conductors are very close to their point of touching but conductors are surrounded by Insulator layer.
Though, in case of neutral conductor it is not covered with an insulator.
The significance of Air Bunched cable is proven to be more effective, because the design of normal conductor was very unappealing and an external force (as Storm) can make the conductor to touch and in result short circuit could happen, Sometime the fire can also take place in drier areas.