The power cable is designed for transmission and distribution of electrical energy in stationary installations. Power cables are used in a wide variety of electrical, and radio engineering schemes. These are tens of thousands of various cables and wires, the diameters of which can range from a few millimeters to a fraction of a meter. The number of conductors in these cables is from 1 to 6. In general, low-voltage power cables are produced by four-core cables. The material of the conductors is copper and aluminum. As insulation of low-voltage cables, paper impregnated with oil-and-tampering compounds is used; PVC - plastic; cross linked PE. In addition to the basic elements, shields, zero conductors, protective earth conductors and fillers can be included in the construction of power cables. Current-carrying veins are intended for passage of an electric current, they happen the basic and zero. Core wires are used to perform the main function of the cable - the transmission of electricity through them. Zero conductors are designed to flow a difference in phase currents (poles) with an uneven load.