Until about the 2000s, overhead power transmission lines (power lines) under construction were installed open. What does this mean? The power line consisted of four open wires: the 1st, 2nd and 3rd phases, plus the 4th “zero” one. The wires were pulled between insulators mounted on support poles at such a distance to prevent a short circuit.
The circuit was not perfect. Firstly, in conditions of strong wind, the wires sometimes overlapped, throwing out sheaves of sparks. Such "fireworks" could easily de-energize small towns. Secondly, humid air is not the best insulator, therefore, energy losses were significant.
Later, special self-supporting cables, such as SIP 4 4x16, began to be used for laying overhead power lines, the technical characteristics of which allow avoiding electricity losses and preventing minor accidents.
Decipher the marking
What do the letters and numbers mean in the cable designation? Like any wire, SIP 4 4x16 specifications can be read on the marking.
Self-supporting
Not every wire can be used for laying overhead lines. When tensioned, the insulation material and the metal of which the conductive wires are made experiences significant loads. The strength of the cable should be such as not to burst under the influence of its own weight, tensile forces and external factors.
Insulated wire
The number "4" immediately following the acronym SIW indicates the type of wire construction (there are five types of SIW products in total).
4 x 16
The cable has four separate conductors with a cross section of 16 mm 2 each, isolated from each other.
Device
How is the wire SIP 4 4x16 arranged. The technical characteristics of any power cable depend on the design, the location of the main elements and the material from which they are made. Each SIP core consists of seven separate wires, with six outer wires wrapped around one central one. The central element is made of a special aluminum alloy, which has high tensile strength, the outer ones are made of aluminum.
Each of the four cores is packed in its own PVC insulating sleeve. And finally, all four cores are covered with one common sheath of the same material.
Specifications
For a SIP 4 4x16 product, technical characteristics are determined by its purpose: to transmit a current of sufficiently high power, to allow the possibility of installing power lines through the air without additional supporting devices, and to withstand any atmospheric effects. The last task is solved by using special thermostabilized polyvinyl chloride in the insulation of the wire, which is resistant both to temperature extremes and to the effects of ultraviolet solar radiation.
The technical specifications declared by the manufacturer for SIP 4 4x16, the power of the transmitted current, look like this:
- working temperature corridor: from - 55 ° to + 55 ° ;
- installation at air temperature from - 21 ° and above;
- temperature increase during operation to + 95 ° C;
- the maximum allowed voltage is up to 1 kV;
- the estimated life of the wire is not exposed to short circuit - not less than 45 years;
- allowable power of powered consumers: at a voltage of 380V - 38 kW, at a voltage of 220V - 66 kW.
Application area
The laying of overhead lines for a small street and the branch system from the power pole of the power transmission line directly to the house are the main areas of application of SIP 4 4x16. The technical characteristics of this cable allow it to be used in any climatic zone of Russia, including for power supply to coastal structures, when the aggressive effects of sea salt water harm even power lines.