In order to protect a person from the harmful effects of the properties of electricity, special protective devices are used: RCDs, fuses, automata (circuit breakers) and other safety equipment. The most popular human security system is the ground loop. This is a specific grounding device, the purpose of which is to connect individual parts of electrical equipment to the "ground". Or, in other words, electrodes (diverters) connected to each other in a horizontal and vertical plane, placed under the soil surface at a certain depth.
Loop resistance is affected by:
- type, structure and condition of the soil;
- electrode properties;
- electrode depth;
- number of electrodes.
Functionally, grounding is divided into two types:
- Protective - designed to protect devices onelectric traction from a short circuit, people from the harmful effects of dangerous currents that occur at the time of a malfunction.
- Working - maintains the required performance of the electrical installation through the grounding of its current-carrying parts.
Process of contour creation
Don't let the question of how to make a ground loop scare you, because putting it together in practice does not cause serious difficulties. In the role of diverters for grounding, metal corners with a side width of 45 or 60 mm, pipes of various diameters can be suitable. The grounding scheme in the form of a triangle is good in that if the connection of the diverter in one of the lines is possible, the parallel line remains in working condition.
Peaty soil, loam type and clay with a high degree of moisture are best suited for mounting the circuit. The worst type of soil is rocky soil.
It is recommended to choose a certain place to assemble the ground loop, the area near the switchgear can be considered the best place. Grounding conductors must be made of copper alloys or black steel or unpainted galvanized.
A trench is dug with a shovel in the form of a triangle, the sides are 3 meters each, the depth is small - 0.5-0.8 meters. A steel ground electrode 2.5-3 meters long is hammered into the vertices of the triangle. The ends can be pointed so that the metal passes into the ground more easily. We leave a little above the ground, up to 20 cm, weld a horizontal steel strip to them, leading to the power electrical panel. Placeswelding, it will not be superfluous to treat it with anti-corrosion paint or, for example, bitumen.
After installation, the ground loop is measured, during which a control measurement of its resistance level is carried out. This is done with a device called a megohmmeter. In the future, repeated measurements are made at least once a year. To do this, it is necessary to close an artificial circuit with an electric current through a grounding device, then make control measurements of the voltage drop in the circuit. An auxiliary electrode is placed next to the main electrode and connected to a source. Measuring device near the zero potential fix the magnitude of the voltage drop on the main electrode. With this method, the ground loop is measured more often than other methods.
