Electrical cable Uses

6 inch (15 cm) outside diameter, oil-cooled cables, traversing the Grand Coulee Dam throughout. An example of a heavy cable for power transmission.Fire test in Sweden, showing fire rapidly spreading through the burning of cable insulation, a phenomenon of great importance for cables used in some installations.500,000 circular mil (254 mm2) single conductor power cable
Electrical cables are used to connect two or more devices, enabling the transfer of electrical signals or power from one device to the other. Long-distance communication takes place over undersea communication cables. Power cables are used for bulk transmission of alternating and direct current power, especially using high-voltage cable. Electrical cables are extensively used in building wiring for lighting, power and control circuits permanently installed in buildings. Since all the circuit conductors required can be installed in a cable at one time, installation labor is saved compared to certain other wiring methods.
Physically, an electrical cable is an assembly consisting of one or more conductors with their own insulations and optional screens, individual covering(s), assembly protection and protective covering(s). Electrical cables may be made more flexible by stranding the wires. In this process, smaller individual wires are twisted or braided together to produce larger wires that are more flexible than solid wires of similar size. Bunching small wires before concentric stranding adds the most flexibility. Copper wires in a cable may be bare, or they may be plated with a thin layer of another metal, most often tin but sometimes gold, silver or some other material. Tin, gold, and silver are much less prone to oxidation than copper, which may lengthen wire life, and makes soldering easier. Tinning is also used to provide lubrication between strands. Tinning was used to help removal of rubber insulation. Tight lays during stranding makes the cable extensible (CBA – as in telephone handset cords).[further explanation needed]
In the 19th century and early 20th century, electrical cable was often insulated using cloth, rubber or paper. Plastic materials are generally used today, except for high-reliability[clarification needed] power cables. The first thermoplastic used was gutta-percha (a natural latex) which was found useful for underwater cables in the 19th century. The first, and still very common, man-made plastic used for cable insulation was polyethylene. This was invented in 1930, but not available outside military use until after World War 2 during which a telegraph cable using it was laid across the English Channel to support troops following D-Day.[2]
Cables can be securely fastened and organized, such as by using trunking, cable trays, cable ties or cable lacing. Continuous-flex or flexible cables used in moving applications within cable carriers can be secured using strain relief devices or cable ties.
At high frequencies, current tends to run along the surface of the conductor. This is known as the skin effect.