As the name implies, Power Cables are meant to transmit power. It is obvious that they are abundantly available, but their classification and hence use, calls forth various deciding factors like voltage rating, the number of conductors, the environmental conditions etc. For instance, military power cables. They are usually designed for voltage up to 600 V and range of their size is #10 AWG – #40 AWG.
Primary building-blocks of all power cables are conductor, insulation, and sheath or protective covering (shown below). They are the hallmarks of cables strength, cost, efficiency, and reliability. And due to their utmost significance, today we are going to dedicate them a complete blog in order to discuss them thoroughly.
Labeled View of Typical Power Cables
The most prominent and widely used conducting material in power cables is Copper. Due to its supreme conductivity, Copper has been set as the standard with which conductivity level of other conductors is compared through a numerical number, called IACS (International Annealed Copper Standard). IACS is the relative conductivity of a conductor relative to Copper, and is expressed in percent. It is directly proportional to metal conductivity. Copper has got 100 IACS, Gold 70 and Aluminum 61. Choice of conducting material, therefore, is an important consideration which must be kept in mind before opting for power cables.
Power cables are insulated to gain toughness, flexibility, and reluctance to erosion. In order to provide enough mechanical protection, minimum insulation thickness is set according to its minimum physical properties. Commonly used insulation is butyl rubber, EBK, and SBR. In elevated-temperature environments, special purpose insulation is used like TFE, FEP etc. It should be noted that corona discharge, breakdown voltage, and dielectric constant are less important for the performance of low-voltage power cables, like military power cables etc. However, for extra high-voltage and ultra high-voltage cables, these parameters become vital and thus can’t be ignored.
In power cables, commonly used compounds for sheath (also called Jacket material) are Polychlorophrene. Besides them, PVC, SBR, chlorosufonated polyethylene, and some ethane family polymers etc are also used. Sometimes there arises a need for resisting some missile fuels. So in this case, Butyl rubber is used usually.
Due to ever increasing demand of electricity, industries have been struggling hard to produce high-quality power cables. And it is the fruit of their hard work that now-a-days every kind of power cables are available in national and international markets, ranging in quality from good to best. Only that industry will win the race which succeeds in gaining customers’ trust and satisfaction.