2.5 meters, grounding resistance is generally less than 0.4 ohms. It is best to use an angle to hit the soil (general angle 2.5 meters, hit the ground), the wire should be firmly fixed at one end of the angle, the fixed point can be buried in the ground.
The bottom of the pit can be added charcoal industrial salt, irrigation, until it meets the requirements. You can also use a few angle steel spaced a few meters apart lined up to hit the ground, and then welded flat steel connection, leading to the grounding wire.
Current flow through the above three grounding electrodes will cause the grounding electrode potential increases, affecting the safety of people and equipment. For this reason, the grounding electrode potential rise must be limited, or take appropriate safety measures to ensure equipment and personal safety.
Expanded information:
Earth resistance
Earth resistance value and soil conductivity Usually according to the requirements of the grounding resistance value, to determine the shape, size, number of buried grounding body and its arrangement, for the high soil resistivity areas (such as mountainous areas), in order to save metal materials, can take measures to improve the soil conductivity.
In the grounding body around the soil filled with high conductivity substances or in the grounding body around a layer of resistance reduction agent (containing water and strong medium of curing resin), etc., in order to reduce the grounding resistance value.
When the grounding body flows into the lightning current, due to the lightning current amplitude is very high, the potential on the grounding body is very high, in the soil around the grounding body will produce a strong spark discharge, the soil conductivity increases accordingly, which is equivalent to the lowering of the resistance of the scattering current.
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