Resistance of grounding pays off on the basis of standard templates and formulas. The obtained data allow to get optimum option of ready grounding. Predesign is necessary because at a small or big indicator of resistance the grounding device will not work.It is required to you
- calculation formulas;
- summary table of specific resistance of soil.
Calculate grounding resistance for several electrodes on the following formula:
R = R1/KIN, where R1 – resistance of one electrode, Ki – efficiency, N – quantity of single electrodes in the grounding device.
When performing this calculation it is not necessary to consider a contribution of the grounding conductor acting as a connector.
Based on the same basic data, as at calculation of grounding for several electrodes, carry out calculation of quantity of electrodes. Use the following formula:
N = R1/KIR, the State Duma of R1 – resistance of one electrode, R – resistance necessary for functioning of a multielectrode grounding conductor (the size received in the previous calculation), Ki – efficiency.
Round the received result of necessary quantity of electrodes towards increase.
Connect electrodes among themselves, and then to object for which the grounding device by means of a copper rod iron or a steel strip is intended. For copper the optimum section of the conductor is considered 70 mm2, for steel – 160 mm2.