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The Facts
o Electrical grounding is vital because it provides a zero potential or ground potential (a reference voltage level) against which all other voltages in a system are measured, according to techtarget.com. An effective electrical ground connection also minimizes equipment interference, reduces risk of lightning-induced damage, and eliminates electrostatic buildup in system components.
Function
o The primary function of electrical grounding is to take away unwanted buildup of electricity. When a point is connected to the ground, it stays in constant voltage regardless of the rest of the system. The Earth is the ultimate ground, because it has the ability to absorb an almost unlimited amount of electrical charge. The actual mechanism consists mainly of a ground rod installed into the soil, according to techtarget.com.
Introduction
o Starting in 1820, long distance electromagnetic telegraph systems used two or more wires to carry signals and return currents. Around 1836, Karl August Steinheil, a German scientist, discovered that the ground can be used as a return path to complete a circuit. He proposed that the Earth could function as a return conductor in telegraphy if the wire terminals were buried beneath the ground, according to Britannica.com. This development greatly changed the design of telegraph receivers, because it made the return wire unnecessary. As a result, the cost associated with telegraphic lines also decreased.
Early History
o By 1851, there were more than 50 telegraph companies in operation in the United States, and the Western Union Telegraph Company was one of the most popular. In 1861, the company completed the first transcontinental telegraph line between Saint Joseph, Mo., and Sacremento, Calif. The lines all used electrical grounding, but most still encountered problems, according to slatemaster.com. Most grounding problems resulted from poor conduction (stemming from dry weather), and water often had to be added to the ground rod in order for the telegraph to work.
Modern History
o When the telegraph was replaced by the telephone as the primary communication device over long distances, electrical grounding became used in other devices, including electric railroads, power systems, and a variety of circuits, according to Britannica.com. Today, power grids and other power transmission systems use grounding to prevent hazardous conditions as well as to facilitate in current return. Other uses include the safe diversion of lighting away from buildings and into the ground.
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