Search results
Results from the WOW.Com Content Network
An example implementation given consists of copper rods buried 0.3-0.5m below ground, and spaced 3-7m apart. In situations where space is at a premium, or other difficulties prevent the construction of a proper grounding grid, ground rods may be driven in deeper, and a wire mat may also be used.
The electrodes for electrical grounding are often called ground rods and are often made from steel with a copper clad surface – typically 1 to 2 m long and 20 millimetres (0.79 in) in diameter. These are driven vertically into the ground and bonded together with bare copper wire. [1]
According to the IEEE standards, grounding rods are made from material such as copper and steel. For choosing a grounding rod there are several selection criteria such as: corrosion resistance, diameter depending on the fault current, conductivity and others. [30]
An isolated ground (IG) (or Functional Earth (FE) in European literature) is a ground connection to a local earth electrode from equipment where the main supply uses a different earthing arrangement, one of the common earthing arrangements used with domestic mains supplies.
Long-distance electromagnetic telegraph systems from 1820 onwards [a] used two or more wires to carry the signal and return currents. It was discovered by German scientist C.A. von Steinheil in 1836–1837, that the ground could be used as the return path to complete the circuit, making the return wire unnecessary. [2]
The extremely dry soil conditions would have required hundreds of feet of rods to be driven into the earth to create a low impedance ground to protect the buildings from lightning strikes. In 1942, Herbert G. Ufer was a consultant working for the U.S. Army. Ufer was given the task of finding a lower cost and more practical alternative to ...
No. 7/0, the largest size, is 0.50 inches (500 mils or 12.7 mm) in diameter (250 000 circular mils in cross-sectional area), and the smallest, No. 50, is 0.001 inches (1 mil or 25.4 μm) in diameter (1 circular mil [cross-sectional area] or 0.7854 millionths of a square inch).
The ground reference for all equipment inside the area being protected is separate from the halo. The halo is connected to the main building ground, which may include an underground ring ground outside the building, with vertical conductors especially in the corners of the building.