How is the ground resistance calculated in the instrument control room?
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The instrument control room requires an earth resistance of less than 4 ohms, but how is this calculated? Could anyone give me an example to help me understand?
No, what I mean is that when doing the calculations, in designing this aspect, I need to take into account what thickness of wire and what length of cable are required to achieve a resistance of 4 ohms
Connect the wires using a ground resistance tester for measurement....
No, then how can I calculate how long a cable is needed to achieve a resistance of 4 ohms?
For vertical rods or hollow tubes, if their length is much greater than their diameter, the resistance can be calculated using the following formula: ρ/2πL, where ρ represents the soil resistance； L — Burial length of vertical bars or hollow tubes ； d — diameter of the vertical rod or hollow tube.
Yes, a 16mm cable, but how is the length calculated?