page_title: Earthing system
section_title: Soil resistance
hierarchical_section_title: Earthing system / Soil resistance
caption_attribution_description: English: Multiple soil layers TU-GO
context_page_description: In an electrical installation, an earthing system or grounding system connects specific parts of that installation with the Earth's conductive surface for safety and functional purposes. The point of reference is the Earth's conductive surface. The choice of earthing system can affect the safety and electromagnetic compatibility of the installation. Regulations for earthing systems vary considerably among countries, though most follow the recommendations of the International Electrotechnical Commission. Regulations may identify special cases for earthing in mines, in patient care areas, or in hazardous areas of industrial plants.
  In addition to electric power systems, other systems may require grounding for safety or function. Tall structures may have lightning rods as part of a system to protect them from lightning strikes. Telegraph lines may use the Earth as one conductor of a circuit, saving the cost of installation of a return wire over a long circuit. Radio antennas may require particular grounding for operation, as well as to control static electricity and provide lightning protection.
context_section_description: Soil resistance is a major aspect in the design and calculation of an earthing system/grounding installation. On its resistance depends on the efficiency of the removal of unwanted currents to zero potential (ground). The resistance of a geological material depends on several components: the presence of metal ores, the temperature of the geological layer, the presence of archeological or structural features, the presence of dissolved salts, and contaminants (Porosity and permeability). There are several basic methods for measuring soil resistance. The measurement is performed with two, three or four electrodes. The measurement methods are: pole-pole,dipole-dipole, pole-dipole, Wenner method, and the Schlumberger method.
caption: Vertical stress of a soil
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