Why do you need grounding, and how to connect it in a private house

Virtually all facilities associated with electricity, it is necessary to protect people from electric shock. Everyone knows why grounding is needed, but few people imagine how to properly install it, so that it fully fulfills its functions.

If you connect all the metal parts of the equipment to the grounding device, then when the potential is induced on them, the electric current will go to the ground. Then when you touch the metal through a person will pass a much smaller current, not posing a danger for him.

How is electricity supplied to consumers?

Electric power comes from the source through power lines first to the substation, and then to the consumers. Three phase wires are used for its transmission. The fourth conductor is the earth. In a three-phase network, the transformer windings of the substation are connected according to the "star" scheme. A common point (neutral) with zero potential is grounded. This is necessary for the normal operation of electrical equipment. This grounding is called working, and not protective.

The apartment is usually supplied with a voltage of 220 V between the conductors of the phase and the neutral to the common electrical panel. In a private house, the input can be 380 V - three phases and neutral. Then the wires diverge to the sockets and lighting devices throughout the rooms. Here, too, we should not forget why earthing is needed. To protect against electric shock, one more grounding wire is laid along with the phase and neutral conductors.

How to protect yourself from electric shock?

One way that eliminates electric shock or significantly reduces it is the installation of a grounding device. Why do we need a ground loop? It is necessary for household appliances with metal housings: washing machines, electric stoves, refrigerators, etc.

When building the potential on the metal housings of home equipment, the current must go to the ground. But for this, it is first necessary to make the device in the form of a metal structure, creating an electrical contact with the ground. It can be integral or consist of conductive elements immersed in the ground.

Grounding in the socket

Why is it necessary to ground electrical appliances in the presence of metal housings or other elements? This question is understandable to many. They may be accidentally energized when the insulation of the wires is broken or short-circuited, which is dangerous for the person at the time of contact.

This also applies to metal parts of lamps and chandeliers. In the residential building, a grounding conductor of 2.5 mm ² cross-section is laid from the electrical panel to each outlet. Why do I need an earthed socket? This is necessary to connect the ground through its contact to a household appliance. Otherwise, it would be necessary to lay the tire throughout the apartment and make connections from it to the body of each device, which is not very aesthetic.

The grounding contacts are arranged so that they are connected first, as soon as the plug from the cord of the household appliance is inserted into the socket. If the sockets are connected by a loop, grounding is fed separately to each of them from the junction box.

Earthing installation

So, why do you need grounding in an individual house? It is made in the form of a closed loop. The shape can be any, but the least amount of material is spent on a triangular shape. Along the perimeter of an equilateral triangle, a trench is dug in the ground to a depth of 1 m, and steel pipes or corners with a length of 2.5 m are clogged in the tops. To protect against corrosion, it is better to use materials with zinc or copper coating. Do not paint electrodes. You can only varnish the place of welding.

The electrodes should protrude 20 cm from the bottom of the trench. The contour is scraped with a strip, and a grounding conductor from the same material to the house is removed from it. A bolt is welded to the free end, and a PE wire of 6 mm ² or more is inserted into the electrical panel. An ohmmeter checks the value of the electrical resistance of the circuit. According to the requirements of the PUE for residential buildings, it should not be more than 30 Ohm.

If the indicator exceeds the set limit, additional corners are hammered around the contour, and a jumper is made. In this way, the area of contact between the structure and the ground is increased. To reduce the resistance of the circuit, the wire from it is replaced by a copper conductor with a higher conductivity. After the trench is filled with soil. Crushed stone, sifting or building debris to apply for this is not allowed. Use a material that retains moisture: clay, peat, loam.

Equipotential bonding

Today even children know why grounding is needed. It is important to ensure a reduction in the potential difference on the surface of the earth, so that the touch voltage and the step voltage are not acting on the person. On the site located above the closed circuit, the potential varies smoothly, and beyond it the recession arises abruptly. To prevent this from happening, horizontal steel strips connected to the electrodes are buried outside.

According to the requirements of the PUE, protective earthing is made of copper. On sale there are special sets, but they have a high cost. For earthing designs of private houses, steel parts are usually used.

Conclusion

Let's sum up. So, why do you need a grounding in a private house? First of all, this is connected with protecting people from dangerous electric shock. It is important to properly equip the ground loop and make the necessary electrical connections. The health and safety of the tenants depends on how it is assembled and the materials selected.