An earthing (combination of protective conductors and earth electrode) is a permanent, well-conducting connection to the earth, without the interposition of a fuse or switch. An earthing consists of one or more earth electrodes, an earth conductor, and protective conductors.
how ground electrode
How to make a ground electrode. The spreading resistance of the ground electrode must be less than 100 ohms. In order not to create any additional conditions for the installation, it is best to ensure that the spreading resistance of the earth electrode is less than 30 ohms. The ground electrode is placed as a ground loop. If this is not possible, use is made of “additional earth electrodes”, such as the metal conductor buried horizontally in the ground, the bars, pins, or conductors driven vertically or obliquely into the ground.
The ground loop
For any new building where the bottom of the foundation trench is at least 60 cm deep, the earth electrode must include at least one loop placed on the bottom of the foundation trench below the outer walls. The ground loop must consist of a solid conductor with a circular cross-section of at least 35 mm2 and without welding. As far as possible, the loop comprises only one conductor, however, the use of several interconnected conductors is allowed in some cases. The ground loop conductor must be bare hardened electrolytic copper or leaded copper. The latter should be used if the site in which the conductor is placed is not likely to provide the necessary guarantees against harmful corrosive action on the copper. The earth loop must be installed directly against the ground and covered with earth in such a way that it does not come into contact with the material of the foundation walls (mortar, concrete, reinforcement … ). The ends of the ground loop must remain accessible for examination. If the ground loop is composed of several conductors placed in series, the ends of each conductor and their connections must remain accessible for examination.
additional ground electrode
If a ground loop cannot be installed (e.g. when the depth of the foundation trench is insufficient) or when the spreading resistance of the ground electrode formed by the ground loop is insufficiently small, ground electrodes called “additional ground electrodes” must be used.
The metal conductor buried horizontally in the ground
The metal conductor buried horizontally in the ground must be a solid conductor of circular cross-section made of copper or leaded copper (same condition as the ground loop). Its cross-section is at least 35 mm2 and the conductor must be buried at least 0.80 m deep.
Metal bars, pins, or conductors are driven vertically or obliquely into the ground
The grounding bars or pins must be at least 1.50 m long. The driven length below the level -0.60 m must be at least 1.50 m.
Grounding bars must be full and of circular cross-section. Their diameter must be at least 14 mm if they are made of copper or copper-plated steel or 19 mm if they are made of galvanized steel.
The grounding pins consist of a straight or helical metal profile. If the grounding pin is made of galvanized steel, the side of the profile must be at least 60 mm with a thickness of the wings and the core of at least 4 mm. the minimum cross-section must have a diameter of at least 19 mm. The thickness of the wings must be at least 3 mm.
Ground Driven Conductors
The conductors driven into the ground consist of bare hardened electrolytic copper with a cross-section of at least 50 mm2. The conductor must be driven into the ground by mechanical vibrations. A steelhead must be placed on the end of the guide in order to avoid any damage during driving.