High voltage cables are used to transmit substantial quantities of electrical power either above ground or underground. Numerous industrial and scientific equipments require the delivery of high voltages from an external high-voltage source. In order to deliver these high voltages, special high-voltage cables have been developed for this purpose. In general, it is desired that the high-voltage cables are characterized by good insulating properties. High voltage cables typically have two conductors, an insulated phase conductor and a bare neutral conductor consisting of a number of wires that are separately helically wound about the length of the first conductor. The neutral conductor also acts as a shield for the phase conductor against electrical stress. This type of cable is commonly referred to as a concentric neutral cable. Three such cables are employed for three phase electrical service. High voltage cables may be classified into two categories. The first category includes a cable system in which copper-conductor cables are used in a general manner, but in which downstream portions employ cables which contain a ferrite core portion in order to suppress noise. The second category includes a cable system which uses reinforced cables made of aramid fiber, glass fiber, etc., the surface of which is covered with conductive carbon to make the cable conducting. With this type of cable, noise is suppressed by increasing the impedance of the carbon portion of the conductive cables. A typical high voltage cable has a centrally located electrical conductor that is covered by a semiconducting conductor shield to smooth out the electric field that accompanies current flow through the conductor. Over the semiconducting conductor shield is applied the insulation having a thickness dependent upon the voltage rating of the cable. Over the insulation another layer of semiconducting material is applied to provide a uniform equipotential electrically conducting surface. A high-voltage cable generally uses a central copper conductor having a diameter which may vary from a few millimeters to a few centimeters. High voltage cable is provided with a shield conductor outside of the cable itself to provide a return circuit for load currents and also to maintain the outside surface of the cable at ground potential. This shield conductor often takes the form of a number of wire braids wrapped about the cable jacket and is termed a concentric neutral. In many pulsed high voltage applications, a high voltage cable transfers a pulse of energy from a local source location to a remote load location. The cable is often connectorized, which allows it to be disconnected for maintenance or other purposes. In order to avoid the entry of water or water vapours through the outer coating to the cable conductor the outer coating preferably consists of metal or a metal sheet in combination with an outer layer of PE or PVC (layer coating). For further details click here