The New Student's Reference Work/Cables, Electric

Ca′bles, Electric, are wires especially prepared for carrying electric currents underground or under water. The underground cable consists essentially of a cylinder of insulating material, such as guttapercha, in which are imbedded one or more copper wires. These coppper wires do not touch each other throughout their length. The guttapercha keeps the moisture out and keeps the electric current in. The cable is generally placed inside a lead sheathing, which preserves its flexibility and at the same time furnishes protection from mechanical injury. It is now the custom to put a large number of conductors—sometimes, for telephone lines, as many as a hundred—in one lead sheath.