Grounding is one way to increase the safety of electrical appliances. While the electrical device is working properly, there is no need for grounding. But each of us was faced with the breakdown of devices, even produced by well-known companies. Breakdowns can be very diverse. Including damage to the insulation and, as a consequence, getting the phase on the body of the product. In the event of such a breakdown, the confluence of several other, quite real circumstances, can become fatal. For example, a woman can unload a damaged washing machine, leaning against a water pipe or radiator.
Many modern electrical appliances are equipped with safety systems. But also it will not be superfluous to equip the power supply system of the RCD( protective shutdown device).
Device for protective shutdown
The principle of operation of the device is that - the current-carrying parts of devices to which a person can touch, are connected to the ground loop. Thus, when the phase hits such areas, a short circuit occurs, and the RCD switches off the current supply. Of course, the automation only works if the device is grounded. Even if the household appliance is not equipped with a fuse or an RCD, grounding will save a person's life, since the current will pass straight from the phase to ground, bypassing the human body due to resistance, since the human body's resistance is about 1000 Ohm, and the grounding is much lower. Having convinced of the undoubted utility of grounding, let's proceed to its installation.
Earthing system installation in the country house
A grounding device is a system of conductive rods immersed in the ground and connected to each other. The most important property of grounding is resistance - the lower it is better there. If you only use grounding for household appliances, its resistance should not be more than 30 ohms, and if you use it with the lightning detector, the resistance should not exceed 10 ohms. This can be achieved in several ways: increasing the depth of immersion of the rods, increasing the distance between the rods, increasing the number of rods, flooding the soil with saline solution.
The rods must be at least 3, can be 4 or more. Depending on the number of rods, along the perimeter of the conditional triangle, or a square with side not less than 1.2 m( the more, the better) dig the depression to a depth of 0.5 m.
Earthing diagram on the dacha with their own hands
At the tops of the dug out figure, hammer the rods into the ground. The core can be a gon, armature, pipe. In general, what is at hand. Score to a depth of at least 2 m. The deeper, the better. Experience shows that doubling the depth of immersion of the rod by 40% reduces the resistance. You can use a heavy sledge hammer or electric hammer. Do not forget to sharpen the rod first. You can simply cut off the end of the Bulgarian at an acute angle. This will make it more likely not to hit the stone. If the ground is rocky and you can not greatly deepen the rods, increase the distance between them and the number of rods themselves. In this case, do not dig the connecting channels, but first hammer the rods. And so, the rods are clogged. Connect them together by welding with a metal strip 40x4 or something else. If for any reason it is not possible to use welding, the contour parts can be joined together and bolted, but in this case, try to achieve the most reliable contact. With the same strip or wire rod 12-15 mm, ground to the house. Proceed from the fact that the cross-section of the conductor connecting the rods and connecting the ground to the house should be about 150 mm2 for steel or 50 mm2 for copper. After connecting all the parts, measure the resistance of the circuit.(It is unlikely that you will be able to measure resistance yourself.) You need a special device and some skills. Therefore, invite a specialist in advance. If the resistance is too high, add another pin and connect it to the others.
Before filling with earth, take a picture of the contour with the reference to the building. In the future, this may come in handy. And in general, all the wiring in the house, as well as other communications before plastering or other facing work, take pictures with the ruler.
The ground loop does not have to be triangular or square. It is quite suitable and this option.
Sample ground loop
Or this - When the pins in the ground are not clogged, and the current goes to the ground due to the large area of the frame.
Earthing circuit diagram
The system of electrical safety of the house will complement the system of potential equalization( EMS).
Its essence is to connect all the potentially dangerous surfaces among themselves. As you know, the voltage is the potential difference. Thus, if a person touches a surface with a high potential and at the same time a low surface, the current will pass through the human body from the first to the second. If all the surfaces in the room are interconnected, then the potential for all will be equal. In the case of such a system, all the metal pipes of communications( water, gas, heating), metal parts of the building frame, ventilation systems, ground loop and neutral conductor of the power supply system must be connected to each other.
