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Earth-return telegraph is the system whereby the return path for the electric current of a telegraph circuit is provided by connection to the earth through an earth electrode. Using earth return saves a great deal of money on installation costs since it halves the amount of wire that is required, with a corresponding saving on the labour ...
In electric power distribution systems, a protective earth (PE) conductor is an essential part of the safety provided by the earthing system. Connection to ground also limits the build-up of static electricity when handling flammable products or electrostatic-sensitive devices.
The choice of earthing system can affect the safety and electromagnetic compatibility of the installation. Regulations for earthing systems vary among countries, though most follow the recommendations of the International Electrotechnical Commission (IEC). Regulations may identify special cases for earthing in mines, in patient care areas, or ...
For example, since there is only one line, winds can't cause lines to clash, removing a source of damage, as well as a source of rural bush fires. Since the bulk of the transmission line has low resistance attachments to earth, excessive ground currents from shorts and geomagnetic storms are more rare than in conventional metallic-return systems.
The electric telegraph was slower to develop in France due to the established optical telegraph system, but an electrical telegraph was put into use with a code compatible with the Chappe optical telegraph. The Morse system was adopted as the international standard in 1865, using a modified Morse code developed in Germany in 1848. [1] The ...
In 1838, Steinheil installed a telegraph along the Nuremberg–Fürth railway line, built in 1835 as the first German railroad, which was the first earth-return telegraph put into service. By 1837, William Fothergill Cooke and Charles Wheatstone had co-developed a telegraph system which used a number of needles on a board that could be moved to ...
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Important examples of these single-wire systems were the Morse telegraph (1837) and the Cooke & Wheatstone single-needle telegraph (1843). In such systems the cost of a return conductor was fully 50 per cent of the cable costs. It was discovered that a return conductor could be replaced with a return path through the Earth using grounding ...