In order to protect a person from harmfulThe effects of electrical properties are applied to special protective devices: RCDs, fuses, automatic devices (circuit breakers) and other safety features. The most demanded human security system is the ground loop. This is a specific grounding device, the purpose of which is to connect with the "ground" of individual parts of electrical equipment. Or, in other words, connected to each other in the horizontal and vertical plane electrodes (diverters) placed under the surface of the soil at a certain depth.
The loop resistance is affected by:
- type, structure and condition of the soil;
- properties of electrodes;
- depth of occurrence of electrodes;
- number of electrodes.
Functionally, the grounding is divided into two types:
- Protective - designed to protect devices on electric traction from short circuits, people from the harmful effects of dangerous currents arising at the time of the malfunction.
- Working - maintains the required operability of the electrical installation through the earthing of its current-carrying parts.
The process of creating a path
Do not be intimidated by the question of how to do it.ground loop, because to assemble it in practice does not cause serious difficulties. In the role of divertors for grounding, metal corners with a side width of 45 or 60 mm, pipes of different diameters can approach. The grounding scheme in the form of a triangle is good in that if the divertor can not connect in one of the lines, the parallel line remains operable.
It is recommended that you select a specific place toto assemble the earthing loop, the optimal place can be considered the area near the switchgear. Earthing should be made of copper alloys or from black steel or galvanized without painting.
The shovel digs out a trench in the form of a triangle,sides of 3 meters, the depth is small - 0.5-0.8 meters. At the top of the triangle, a steel earthing rod 2.5-3 meters in length is clogged. The ends can be sharpened so that the metal can easily pass into the ground. Above the ground we leave a little, up to 20 cm, welded to them a horizontal steel strip leading to the power electric shield. Welding places will not be superfluous to treat with anti-corrosion paint or, for example, bitumen.
After installation, a contour measurement is performedground, at which the control measurement of its resistance level is carried out. This is done by an instrument called a megaohmmeter. In the future, repeated measurements are made at least once a year. For this, an artificial circuit with an electric current needs to be closed through the grounding device, then check the voltage drop in the circuit. Near the main electrode place an auxiliary and connect it to the source. The measuring instrument near the zero potential fixes the magnitude of the voltage drop across the main electrode. In this way, the ground loop is measured more often than other methods.
