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A weak point in most lightning diversion systems is in transporting the captured discharge from the lightning rod to the ground, though. [18] Lightning rods are typically installed around the perimeter of flat roofs, or along the peaks of sloped roofs at intervals of 6.1 m or 7.6 m, depending on the height of the rod. [19]
Bare-wire or ground-return telecommunications can be compromised by the ground-return current if the grounding area is closer than 100 m or sinks more than 10 A of current. Modern radio, optic fibre channels, and cell phone systems are unaffected.
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 ...
A lightning-struck tree in the Toronto Islands, clearly shows the path that the charge took into the ground. Trees are frequent conductors of lightning to the ground. [27] Since sap is a relatively poor conductor, its electrical resistance causes it to be heated explosively into steam, which blows off the bark outside the lightning's path. In ...
There are several types derived from copper and steel: copper-bonded, stainless-steel, solid copper, galvanized steel ground. In recent decades, there has been developed chemical grounding rods for low impedance ground containing natural electrolytic salts. [31] and Nano-Carbon Fiber Grounding rods. [32]
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]
The large area is required to dissipate the high current of a lightning strike without damaging the system conductors by excess heat. Since lightning strikes are pulses of energy with very high frequency components, grounding systems for lightning protection tend to use short straight runs of conductors to reduce the self-inductance and skin ...
A halo ground is a type of ring ground that, instead of being installed outside and underground, is installed inside, near the top of a building or structure. The ground reference for all equipment inside the area being protected is separate from the halo.