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Usually the former refers to a single, solid metallic conductor, with or without insulation, while the latter refers to a stranded conductor or to an assembly of insulated conductors. Power cables operate on direct current or low-frequency alternating current, while communication cables operate at higher frequencies. Copper or aluminum is chosen for high electrical conductivity, while stranding gives the cable 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. The insulation are made of polymer, plastic layer that cover the conductor it from external contacts. A marble bust of Bright was executed by Count Gleichen (Prince Victor of Hohenlohe-Langenburg), and exhibited at the Royal Academy; plaster duplicates are now in the possession of the Institutions of Civil Engineers and of the Electrical Engineers. Illustrative of these usages and of the special conditions to be met are cables for use in steel mills and boiler rooms (high temperature), on mobile equipment (vibration and excessive flexing), in chemical plants (corrosion), for submarines and mines (mechanical abuse), near nuclear reactors (high radiation), and on artificial satellites (pressure extremes). Simple Usage : The cables should be easily installed without requirement of complex circuits .

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. Another type of electric power cable is installed in underground ducts and is extensively used in cities where lack of space or considerations of safety preclude the use of overhead lines. Though this cable so soon broke down, the mere fact that many successful messages had been sent through it showed that the problem was one which could be solved. Among his later patents was a joint one (No. 466 of 1862) with Latimer Clark on an improved method of applying asphalt composition as a covering to the outside of submarine cables (known afterwards as Bright and Clark's compound), and another in 1876 on fire alarms. Physically, an electrical cable is an assembly consisting of one or more conductors with their own insulations and optional screens, individual coverings, assembly protection and protective coverings. A power cable usually has not more than three conductors, each of which may be 1 inch (2.5 cm) or more in diameter; a telephone cable may have several thousand conductors, the diameter of each being less than 0.05 inch (0.125 cm).

The insulation thickness is a few hundredths of an inch or less. The story of the first Atlantic cable is told elsewhere (see Telegraph), and it must suffice here to say that in 1858, after two disappointments, Bright successfully accomplished what to many had seemed an impossible feat, and within a few days of landing the Irish end of the line at Valentia he was knighted in Dublin. H or U: the first letter is a national or international reference point. All wires running inside this shielding layer will be to a large extent decoupled from external electrical fields, particularly if the shield is connected to a point of constant voltage, such as earth or ground. Aerial and underground power cables compose a major portion of the electrical circuit from the generator to the point of utilization of the electric power. Blue : Phase 3 or distribution of power wire. In the current where every where it is a web of wires and cables at every place the cables play a very vital role in transmission and distribution of electrical power.

The power cables are used for domestic purpose as they can be buries into the ground or can be used overhead. His experiments convinced him of the practicability of an electric submarine cable connexion between Ireland and America; and having in 1855 already discussed the question with Cyrus Field, who with J. W. Brett controlled the Newfoundland Telegraph Company on the other side of the ocean, Bright organized with them the Atlantic Telegraph Company in 1856 for the purpose of carrying out the idea, himself becoming engineer-in-chief. The construction of long submarine cables for either telephone or telegraph service is somewhat different from that discussed previously. The insulation of a telephone cable is composed of dry cellulose (in the form of paper tape wrapped around the conductor or paper pulp applied to the conductor) or of 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.

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