How to make grounding in a wooden house. Grounding in a private house: how to do it right with your own hands

Grounding is one of the most important elements in the field of electrical engineering. There is no voltage in the grounding conductors, and there should not be an electric current in them, but still their importance is even higher than that of the phase lines. Hundreds of meters of grounding conductors are passed in each apartment and private house. What is the purpose of doing this and what does the very essence of grounding mean? What are the risks associated with the lack of grounding and how can a 220V electrical network be grounded without the involvement of experienced electricians (do it yourself)? These and many other questions will be discussed in detail in this article-instructions.

What does network grounding mean?

Imagine a house in which every socket, every lamp, in addition to the phase and neutral wires through which the electrical components of the network are connected, is connected to ground wires. These cables usually do not affect the operation of the devices.

The connection of ground (protective) wires is usually carried out in a home switchboard (distribution) panel, and from there, through one cable, it goes directly to a metal element connected to the ground.

What is the purpose of grounding in a house?

Grounding is carried out for two reasons:

protection- the main reason for the use of grounding in home networks.
Job- for the correct functioning of electrical devices (in homes, only a few devices require grounding for proper operation, for example, computer power supplies).

We are mainly interested in security, which gives rise to another question: how does an iron pin buried in the ground protect us from anything?

Let's assume that the earth (soil, soil) has an electric potential of 0V (this is true in 99.99% of cases). Therefore, if you bury the wire in the ground, then there will be no electrical potential in all the grounded wires laid in the house and attached to it.

Next, through the electrical connectors, we connect these wires to the devices. Inside these devices, protective (earthed) conductors are usually connected to the case (metal) or to any other metal element that is easily accessible to a person during operation of the device and, therefore, should in no case be energized.

Since the case is connected to ground, the potential of which is 0V, the case will have the same potential. If the body has a zero potential and the zero potential approaches it, the current does not flow, that is, an electric shock will not threaten a person.

If the body of the device is not connected to the ground wire and there is a breakdown inside for unknown reasons, an electric potential will arise, and since it is not connected in any way to the ground (directly or indirectly), it has nowhere to “run away”. Therefore, the risk is obvious: a person who has an electrical potential of 0 V, touching a body that has a potential of 220 V, actually becomes a current conductor with this voltage, with all the ensuing consequences.

As a result, as a result of connecting all devices to the ground, the long-term maintenance of the electrical potential on the cases (and other elements) that is accessible to a person during normal operation of the device is prevented. In the event of an electrical breakdown in the case where the latter is grounded, the formation of a short circuit will trip the circuit breaker (not to mention the current differential switch, if any) on the home switchboard and cut off the power before anyone touches the case.

Symbols and designations on the diagrams

In the case of marking network wires, two main signs of mass can be found:

PE- marking of the protective conductor ()
PEN- designation of the neutral conductor, which simultaneously acts as a protective conductor (blue)

In the case of grounding designation on circuit diagrams, you will encounter two:

	General symbol for ground (ground)
	Symbol indicating a grounding clamp having a protective function against electric shock

In many devices, instead of a grounded power plug, a plug is visible that does not have a hole for the grounding prong (lug). This does not mean that the device is not protected against electric shock. The case of the device usually has a so-called rating plate, on which you can find the symbol of two squares (one inside the other).

This means that the device has no accessible external conductive elements (the case is made of plastic), and therefore there is no need to ground it.

Attention! The presence of a plug without a hole on the ground prong is not an indication that the device has adequate protection against electric shock. This is evidenced only by the symbol indicated above.

Electrical networks and grounding schemes

When it comes to home electrical installations, there are four basic network wiring diagrams. And the main difference between them lies precisely in the method of grounding:

Power supply network without grounding (TN-C).
Network with a separate grounding installation in an apartment / house. In the home panel, neutral and protective conductors are connected to each other (TN-CS).
Mains supply with a separate earthing installation, earthed at the same location as the neutral point of the transformer (TN-S).
Network with a separate earthing installation earthed at a different location than the neutral point of the transformer (TT).

We will explain this in more detail on the basis of the first network system discussed.

Network without grounding TN-C

Here is the scheme on which we will be based in all subsequent examples. Let's say there is a transformer, that is, an element located next to the apartment of the house, which supplies electricity to this and neighboring houses. For simplicity, we will install a single-phase transformer here instead of a three-phase one.

Through the transformer winding, voltage is applied to the phase wire (brown). Blue - neutral wire - connected on the other side of the winding and also grounded at the transformer (this is the so-called neutral point). As a result, the electric potential on the neutral conductor is 0V, and the voltage between the phase and neutral wires depends only on the electric potential created by the transformer.

We simplified the drawing to the maximum and removed all the elements that are located between the transformer and the household appliance (the rectangle is a washing machine), that is, fuses, current switches, connectors, and so on. Since the neutral conductor (N) also has a protective function (PE), it is abbreviated PEN here.

There is a washing machine from which three wires are output:

phase and neutral conductors used to power the motor and device electronics
protective conductor connected inside the washing machine to its body

The 220V TN-C network system is most often found in old Soviet houses, where the concept of a protective element was irrelevant.

At first you might think that since the neutral conductor is grounded, why else would the protective conductor also need to be grounded? Because if the neutral conductor is interrupted for any reason, such as overheating and combustion, the device itself will turn off, since the electrical circuit will be interrupted, but due to the lack of grounding of the neutral conductor, there is a possibility that through the washing machine (or any included in the 220V device) the voltage on the phase wire will also appear on the neutral conductor. Since the phase will appear on the neutral wire, it will also be on the protective cable connected to the body of the washing machine, which is a deadly threat.

Networks with a separate ground line TN-CS

Here in the home switchboard, the neutral and protective conductors are connected to each other (TN-CS).

Some improvement is the introduction of an electrical circuit for the TN-CS system. Let's say there are only two wires to the apartment, but in a home switch, the neutral-protective conductor (PEN) can be divided into two (the so-called separation point), a neutral wire and a protective one. What does it give in terms of security?

Before answering this question, look at the two terminal blocks in the above figure. All protective conductors are connected to one, and all neutral - to the other. In the TN-CS system, this is where the PE wires are connected to the N conductors.

If a break in the neutral conductor occurs before the separation point, then the voltage through the phase conductor and the device enters the neutral conductor, and from there to the protective conductor.

But if the damage to the neutral conductor occurs after the separation point, that is, somewhere in the apartment / house, no matter where the failure occurs on the protective conductor and, therefore, there will be no dangerous electrical voltage on the device housings.

The best solution when using this type of circuit is to ground the split points. No matter where the neutral conductor is damaged, no voltage will appear on the PE conductor. The problem is that grounding the connection point of the PE and N terminal block is sometimes difficult to implement, especially in multi-storey residential buildings.

Network with separate ground loop TN-S

This network is earthed at the same location as the transformer neutral point (TN-S).

Such a network system has three wires running from the transformer itself to the device. Neutral and protective conductors are earthed at the same place on the transformer. In this case, electric current flows in the neutral conductor during normal operation. However, in the protective conductor (when everything is in order), except for the zero potential, the current does not flow along the entire length.

Damage to the neutral conductor in any place does not affect the protective conductor in any way, except that the electrical equipment stops working. People are not in danger.

Mains supply with separate earthing TT

A network with a separate line earthed at a location other than the neutral point of the transformer (TT).

The TT electrical network layout is very similar to the TN-S system in terms of security. The only difference is that the protective conductor (with the blue sleeve) is led out of the protective terminal block, which is earthed at a completely different location than the neutral point of the transformer. This network system is often used in single-family homes, where grounding is done for each house separately.

For example, let's open the neutral conductor. This does not have the slightest effect on the defensive line.

How to quickly check the quality of grounding

Let's say you recently bought an apartment in an old house and want to replace the lamp in a chandelier with a metal case that remembers the times of the Great Patriotic War. You don't have (or don't know about) a ground loop. How to know if there is a dangerous electrical potential on the lamp body?

First, touch the body of the chandelier with your palm for a second. If there is even a small electrical potential, you will feel it, but for a fraction of a second it does not pose a threat to human health.

In general, you need to be careful in such cases. Devices with a metal case are everywhere (eg refrigerators, washing machines, boilers), regardless of the year of construction of the building in which we are located.

Ways to create grounding

All electrical components are grounded in such a way that they are physically connected to the earth (soil). We will immediately warn you that taking the ground wire out of the house and sticking it directly to the ground is not a good and effective solution. The ground wire must be connected to something that will have a much larger ground contact area and will withstand decades of humidity and temperature changes. This element is called the ground electrode.

The ground contact surface is important when it comes to ground resistance. The lower the resistance, the better (the faster the electrical potential will be zero in case of problems).

Currently, there are several popular solutions for the manufacture of earth electrodes, to mention a few of them:

An iron rod, several meters deep, thrust into the ground, ending at the top with a connection for connecting a grounding conductor. The length of the rod depends on the type of soil. The lower the electrical resistance of the earth, the shorter the rod can be. In many cases, the use of this type of ground electrode may not be sufficient due to the too small contact surface with the ground and, as a result, high electrical resistance.
Use of steel tape. Wrap around the house about 80-100cm underground. In one place, it is connected to the main ground conductor, which is removed from the electrical system using a connector.
Connecting a ground conductor to a rod that extends from the reinforced concrete base of the building. That is, the connection of the earth to the foundation, which has a large area of contact with the earth and, in addition, does not require additional installation costs. You just need to think about it at the stage of building a house.

Results and wishes

Of course, this topic is not exhausted. We did not mention the cross-sections of protective conductors, the main grounding rods, equations and formulas ... But for a start, this is enough and a lot of useful information has already been received into the piggy bank of your knowledge.

Today, almost every country house is equipped with electrical appliances. The safety of their operation is ensured by connecting the electrical equipment installed in the premises with a grounding device. Properly performed protective grounding will eliminate the possibility of electric shock to people and prevent the failure of household appliances and complex technical devices from overvoltage if they are protected by an SPD. The choice of connection scheme depends on various factors. In a private house, unlike an apartment building, grounding can be done independently. This guide will help you figure out how to connect it.

The main elements of the scheme for connecting the grounding of a country house and the rules for their implementation

The ground connection diagram in a country house is as follows: electrical appliance - socket - electrical panel - ground conductor - ground loop - ground.

The connection begins with the implementation of a grounding device on the local area in accordance with the rules defined in chapter 1.7 of the PUE of the 7th edition. The ground electrode is a metal structure with a large area of contact with the ground. Designed to equalize the potential difference and reduce the potential of grounded equipment in case of a short circuit to the case or the appearance of excess voltage in the mains. The design and depth of its installation is determined based on the resistance of the soil in the area (for example, dry sand or wet black soil).

From the grounding device (grounding) made at the site, we lay a grounding conductor, which we connect to the main grounding bus using a bolted connection, clamp or welding. We select a conductor with a cross section of at least 6 mm2 for copper and 50 mm2 for steel, while it must meet the requirements for protective conductors specified in table 54.2 of GOST R 50571.5.54-2013, and for a TT system have a cross section of at least 25 mm2 for copper. If the conductor is bare and laid in the ground, then its cross section must correspond to that given in table 54.1 GOST R GOST R 50571.5.54-2013.

In the switchboard, the grounding conductor is connected through the grounding bus to the protective conductors laid to sockets with a grounding contact and other electrical receivers in the house. As a result, each electrical appliance is connected to the grounding system.

Dependence of the ground connection scheme on the ground loop

If re-grounding is performed at the power line pole, then the grounding connection scheme in a country house is performed using the TN-C-S or TT systems. When the condition of the networks does not cause concern, the re-grounding of the line should be used as the grounding device of the house and the house should be connected in accordance with the TN-C-S grounding system. If the overhead line is old, or the quality of re-grounding is questionable, it is better to choose a TT system and equip an individual grounding device in the local area.

For a grounding device, first of all, natural ground electrodes should be used - third-party conductive parts that have direct contact with the ground (water pipes, well pipes, metal and reinforced concrete structures of a country house, etc.). (see paragraphs 1.7.54, 1.7.109 of the EIC of the 7th edition).

In the absence of such, we perform an artificial grounding device using vertical or horizontal electrodes that we dig into the ground. The choice of the configuration of the ground electrode is mainly based on the required resistance and the characteristics of the local area.

It is most effective to use if the soil in your area is represented by loam, peat, sand saturated with water, watered with clay. The standard length of the rods is from 1.5 to 3 m. When choosing the length of the vertical electrodes, we proceed from the water saturation of the host rocks in the area. Buried ground vertical ground electrodes are combined with a horizontal electrode, for example, a strip, and to minimize shielding, they are located at a distance commensurate with the length of the pins themselves.

Dependence of the connection scheme on the type of grounding system

Grounding of housing facilities is carried out according to the following systems: TN (subsystems TN-C, TN-S, TN-C-S) or TT. The first letter in the name indicates the grounding of the power source, the second - the grounding of open parts of electrical equipment.

Subsequent letters after N indicate the combination in one conductor or the separation of the functions of the zero working and zero protective conductors. S - zero working (N) and zero protective (PE) conductors are separated. C - the functions of the zero protective and zero working conductors are combined in one conductor (PEN-conductor).

Electrical safety is fully ensured when a decrease in the resistance of the ground electrode does not entail an increase in the indicators of the ground fault current. Consider how the grounding connection scheme depends on the electrical network system installed at the facility.

TN-S earthing system

Figure 1. TN-S system

At facilities equipped with a TN-S system, the zero working and protective conductors are separated along the entire length, and in the event of a phase insulation breakdown, the emergency current is diverted through the protective PE conductor. RCD devices and difavtomat, reacting to the appearance of current leakage through a protective zero, turn off the network with the load.

The advantage of the TN-S grounding subsystem is the reliable protection of electrical equipment and a person from damage by emergency current when using electrical networks. Due to this, this system is referred to as the most modern and safe.

To perform grounding using the TN-S system, it is required to lay a separate ground wire from the transformer substation to its building, which will lead to a significant increase in the cost of the project. For this reason, for grounding private sector facilities, the TN-S grounding subsystem is practically not used.

TN-C earthing system. The need to switch to TN-C-S

Figure 2. TN-S system

Grounding according to the TN-C system is most common for old housing stock buildings. The advantage is that it is economical and easy to implement. A significant drawback is the lack of a separate PE conductor, which excludes the presence of grounding in the sockets of a country house and the possibility of potential equalization in the bathroom.

Electric current is supplied to suburban buildings through overhead lines. Two conductors are suitable for the building itself: phase L and combined PEN. It is possible to connect grounding only if there is a three-core wiring in a private house, which requires the conversion of the TN-C system to TN-CS, by separating the zero working and zero protective conductor in the electrical panel (see clause 1.7.132 of the PUE of the 7th edition) .

Grounding connection according to the TN-C-S system

The TN-C-S grounding subsystem is characterized by the union of the zero working and zero protective conductors in the area from power lines to the entrance to the building. Grounding on this system is quite simple in technical design, due to which it is recommended for wide application. The disadvantage is the need for constant modernization, in order to avoid breaking the PEN conductor, as a result of which electrical appliances may be at a dangerous potential.

Let's consider the grounding connection scheme in a country house according to the TN-C-S system using the example of transition to it from the TN-C system.

Figure 3. Schematic of the main switchboard

As already noted, in order to obtain a three-core wiring, it is necessary to properly separate the PEN conductor in the switchboard at home. We start with the fact that we install a bus in the electrical panel with a strong metal connection with it, and connect the combined PEN conductor coming from the side of the power line to this bus. We connect the PEN bus with a jumper to the next installed PE bus. Now the PEN bus acts as a bus of the zero working conductor N.

Figure 4. Earth connection diagram (transition from TN-C to TN-C-S)

Figure 5. TN-C-S ground connection diagram

Having completed the indicated connections, we connect the switchboard to the ground electrode: from the grounding device we start the PE busbar. Thus, as a result of a simple upgrade, we equipped the house with three separate wires (phase, zero protective and zero working).

The rules for the installation of electrical installations require re-grounding for PE - and PEN-conductors at the input to electrical installations, using, first of all, natural grounding conductors, the resistance of which at a mains voltage of 380/220 V should be no more than 30 Ohm (see clause 1.7 .103 PUE 7th edition).

TT earth connection

Figure 6. TT system

Another variant of the scheme is to connect the grounding of a country house using the TT system with a solidly grounded neutral of the current source. The open conductive elements of the electrical equipment of such a system are connected to a grounding device that does not have an electrical connection with the grounding conductor of the neutral of the power source.

In this case, the following condition must be observed: the value of the product of the tripping current of the protection device (Ia) and the total resistance of the grounding conductor and the ground electrode (Ra) should not exceed 50 V (see clause 1.7.59 of the Electrical Installation Code). Ra Ia ≤ 50 V.

To comply with this condition, “Instructions for the device of protective grounding and potential equalization in electrical installations” And 1.03-08 recommends making a grounding device with a resistance of 30 ohms. This system is quite in demand today and is used for private, mainly mobile buildings, when it is impossible to provide a sufficient level of electrical safety with the TN system.

TT grounding does not require separation of the combined PEN conductor. Each of the individual wires suitable for the house is connected to a bus isolated from the electrical panel. And the PEN conductor itself, in this case, is considered the neutral wire (zero).

Figure 7. TT earth connection diagram

Figure 8. Connection diagram for grounding and RCD according to the TT system

As follows from the diagram, TN-S and TT systems are very similar to each other. The difference lies in the complete absence of electrical connection between the grounding device and the PEN conductor in the TT, which, in the event that the latter burns out from the side of the power source, guarantees the absence of excess voltage on the body of electrical appliances. This is the obvious advantage of the TT system, providing a higher level of safety and reliability in operation. The disadvantage of its use can only be called high cost, since in order to protect users in case of indirect contact, it is necessary to install additional protective power off devices (RCD and voltage relay), which, in turn, requires approbation and certification by an energy supervision specialist.

Conclusion

The grounding scheme in general terms is a connection of its elements: electrical equipment, input distribution board, grounding conductor PE, ground electrode.

To install a grounding device in a country house, you need to understand the features of its connection, depending on the following factors:

method of supplying the electrical network (overhead lines or cable from a transformer substation)
type of soil in the adjacent area where the ground loop is performed.
the presence of a lightning protection system, additional power supplies or specific equipment.

When making the grounding connection yourself, you must be guided by the provisions of section 1.7 of the Electrical Installation Rules. If it is impossible to use natural grounding conductors, we perform a grounding device using artificial grounding conductors. Grounding of a private house can be performed using two systems: TN-C-S or TT. The most widely used modernized system TN-C - TN-C-S, due to the simplicity of its technical design. To ensure the electrical safety of a country house according to the TN-C-S system, it is required to separate the PEN conductor into zero working and zero protective conductors.

Having completed the ground loop, it is necessary to check the quality of its installation, and to measure the resistance for compliance with the PUE standards using special instruments, which may require the involvement of specialists.

Do you need advice on the organization of grounding and lightning protection for your facility? Contact

Electricity in our home makes life easier and more comfortable, but we must not forget that it can also cause serious electrical injuries. One way to protect yourself is to use protective grounding. In addition, some modern electrical appliances, such as microwave ovens, gas boilers, home computer system units, need grounding to ensure their normal operation (reducing interference, reducing the level of harmful radiation).

It is very rare to find a private house or cottage in which grounding is used. The owners of such housing are faced with the choice of hiring workers or doing the grounding themselves. For a 220 V (380v) network, solving this problem is quite simple. Therefore, if you have a desire to physically work, there is no need to buy expensive sets of ready-made earthing switches or hire organizations to perform this work.

In the manufacturing process, a small amount of welding work will be required, if there are no difficulties with this, it remains to purchase metal products and get to work.

Most of our networks are equipped with a solidly grounded neutral, in other words, the neutral wire in the socket at the power plant is connected to the ground. The wire is also grounded at additional points, for example, on power line poles. Unfortunately, the electrical networks are very worn out, and this grounding leaves much to be desired.

Now let's imagine a situation where, due to damaged insulation, voltage hit the device case. If you touch the device, the current will begin to flow through the human body to the ground. It is generally accepted that the human body has a resistance of about 1 thousand ohms, this value increases the rubber sole of the shoe, a dry rug on the floor, etc. . The smaller this value, the stronger the effect of current on the body will be felt.

If there is a ground , current from the damaged device flow to the ground over it. If in this case a person touches the body of the device, then his body becomes parallel connected to the ground conductor. The resistance of the latter is much less than the resistance of the body, so most of the current will flow along the path of least resistance, and the person will feel a slight tingling at most and avoid serious electrical injuries.

For the circuit to work like this, as described above, the grounding system must have a certain resistance:

for a network with a voltage of 380V - no more than 2 ohms;
for a network with a voltage of 220V - no more than 4 ohms.

The requirements for the design of a grounding device for a private house with a 380 V network are higher, therefore, such a circuit can also be used for a 220 V network. During construction, they differ only in that for 380 V, grounding conductors of a larger cross section are used, and the structural elements are made of thicker metal . Therefore, there is no need for separate consider how to make a ground loop for 380 V and 220 V. Consider making a ground for 380 V.

Elements and materials

The grounding device consists of three elements.

The larger the cross section of the metal elements used, the better the currents spread to the ground, and therefore, the whole ground loop works better. In addition, thicker metal will take longer to corrode, so ceteris paribus, thicker metal should be chosen.

The electrical conductivity of hardened rolled metal is lower than that of ordinary steel, for this reason reinforcement should not be used, channel and similar elements of metal structures.

Schemes and dimensions

The ground loop diagram of a private house is a way of locating and connecting vertical ground electrodes. If you are doing 380 volt grounding to the house , the execution scheme may be different, but the main two.

The dimensions of the ground loop for a private house given above are suitable for most cases, but they can be changed depending on specific conditions. For example, if groundwater is located close to your site, then the length of vertical ground electrodes can be reduced to a meter.

If it is impossible to deepen the ground electrodes to the required level, or the site has dry sandy soil, a situation may arise when the finished grounding has high resistance and does not perform its functions. In this case, it is necessary to increase the number of vertical pins. For example, if there is already a triangular contour, you need to step back three meters from it and drive in a rod that is connected to the triangle with a metal strip. It turns out a combination of closed and linear construction schemes. You can make two triangles and connect them together. Do this until the resistance of the circuit drops to the required value.

Location selection

The grounding device is located no closer than one meter from the house.

It is good if the land never dries up in the chosen place, for example, a piece of land on the north side of the house, a lowland, and so on.

We should not forget about precautionary measures, it is necessary to limit visits to a place with a ground loop by animals and people. To do this, grounding must be located where people are excluded, or fenced off.

Before starting excavation, make sure that no pipelines and cables are laid underground.

Grounding check

The method for measuring ground resistance is different from measuring conventional resistance, therefore, special devices are used for such purposes. If you do not have such a device, you can check your circuit with a practical method.

You will need a cartridge with an incandescent lamp with a power of at least 100 watts. One wire from the lamp holder is connected to the phase contact of the socket, and the second to the ground bus. If the lamp shines the same way as during a normal mains connection, the circuit is working correctly. Ideally, the voltage on the lamp in both cases should be the same.

In the case when the lamp shines dimly or does not burn at all, it is necessary to check the places of metal welding and wire connections. If the connections are OK, it is necessary to increase the ground loop.

Work sequence

Protective zeroing

Some people, to save money or out of ignorance, use zeroing in a private house instead of protective grounding. The scheme of the latter is used in enterprises when using industrial equipment. The main purpose of zeroing is to protect equipment from short circuits. Therefore, its use in a private house is impractical, and it cannot replace protective grounding in any way.

Don't skimp on your safety. It is not difficult to make grounding for 220 V in a private house with your own hands. All the necessary tools are available for each owner.

If the wiring in your house is made with two-wire wires, then there is no wire to connect the ground conductor. You can solve this problem without replacing the wiring in the following way. Sockets in the house are replaced from ordinary sockets with grounding, and the ground wire is led along the outer surface of the wall, you can hide it under the plinth or in a decorative plastic box.

For the safe operation of powerful electrical appliances, especially those located in wet rooms (boiler, washing machine), the use of a grounding contact in the socket is not enough. The cases of such devices must be connected with copper conductors directly to the ground bus. To do this, there is a special bolt on the case, marked with a ground icon.

The ground electrode elements are made of ferrous metal, which will gradually break down under the action of corrosion, and at some point the ground will cease to perform its functions. In order not to miss this moment, it is necessary to periodically check the health of the circuit and, if necessary, restore it. Therefore, it will be useful to draw a plan for the location of all elements.

Among the various opportunities to make housing safe, grounding in a private house occupies a special place: the electrical circuit of any modern house will not be approved if it does not provide for a connection to a ground loop.

Scheme of the grounding device of a private house Source tirez.ru

There are several options and schemes for grounding a private house, plus clear requirements for PUE (electrical installation rules) - all this must be known and understood in order for the electricity in the house to be safe.

Why do you need grounding in a private house: the principle of operation

Grounding in a private house is considered an important part of the power supply system. It is mounted for the following purposes:

Protection of the inhabitants of the house from electric shock (when touching a device with broken electrical wiring insulation);

Correct operation of modern electrical devices;

Safe operation of gas equipment;

Efficient operation of lightning protection.

The principle of operation of the system is based on the elementary laws of physics, which say that electric current always moves in the direction of least resistance.

If the insulation of the device is damaged, the current exits (closes) to the case. Such a situation is fraught with malfunctions and breakdowns, not to mention the danger for a person to receive a sensitive discharge by accidentally touching the surface with his hand.

Video description

Capaciously and clearly the grounding diagram of a private house, why it is needed and what it should be - are shown in the following video:

In the presence of grounding, the current is distributed taking into account the resistance of the body and the grounding circuit of the house (in inverse proportion).

A carefully thought-out protective grounding forms an electrical circuit with a resistance much less than that of the human body. The current passing through a person will not have a dangerous effect, and the main charge will go into the ground.

The passage of electric current through the human body in a system without grounding and with grounding Source plotnikov-pub.ru

The main grounding element of a private house is the ground loop - the PUE defines it as metal conductors and ground electrodes (rods or pipes) buried in the ground.

Internal wiring according to modern standards is carried out with a three-wire wire (phase + zero + ground). Protective earth wires connect the circuit to electrical devices.

To ensure safety during thunderstorms, devices designed for this purpose are used - arresters designed for large currents and voltages.

There are currently three mains earthing systems, TN, TT and IT. Mostly in everyday life, one of the varieties of the first of them is used - TN-C, TN-S, TN-C-S.

Video description

About the difference between TN and TT systems - in the video:

Explanation of abbreviations

The first letter indicates the method of grounding the power source, the second characterizes the grounding of the consumer.

T - source (consumer) is grounded;

I - current-carrying parts of the source are isolated from the ground;

N - the consumer is connected to the grounding point of the source (zeroed).

C - conductors N (zero working) and PE (zero protective) are combined into one common conductor PEN;

S - the functions of the N and PE conductors are separated.

Subtypes of the TN system (TN-C, TN-S, TN-C-S) differ in the way the N and PE conductors are connected.

Grounding systems in AC networks Source zen.yandex.uz

TN-C system

In this case, one conductor (N and PE are combined throughout the electrical network) performs both working and protective functions.

This way of organizing the system is ubiquitous in the old housing stock, it is simple to implement and economical. But the lack of a separate protective ground often leads to a short circuit in an emergency (power surges). According to modern standards, reflected in the requirements of the PUE, the TN-C grounding system is prohibited for new buildings. At the same time, there is no mandatory requirement to modernize the old ones (unless a major overhaul is being done).

TN-S system

Here the conductors N and PE are separated, no voltage appears on the housings of electrical appliances. The system is safe and well protects the person, home electrical equipment and building. The main disadvantage is the high cost of arrangement.

TN-C-S system

Combined system. At the output from the power supply, the N and PE conductors are combined in one conductor. A PE protective conductor is added at the entrance to the building.

When deciding which grounding is better for a private house, you should refer to the Code of Electrical Installations. He recommends the TN-C-S subsystem as the main one for most consumers; it is easy to organize and more reliable than others protects against fire due to a short circuit.

On our website you can find contacts of construction companies that offer electrical work services. You can directly communicate with representatives by visiting the exhibition of houses "Low-Rise Country".

Differences of the TN-C-S system Source keaz.ru

Circuit elements, grounding options and required materials

Protective grounding systems (grounding devices) are usually divided into the following elements:

grounding conductor (ground loop); there is a natural and artificial option;

grounding conductors.

According to the PUE, it will be preferable to use a natural ground electrode (metal fence or pipeline) if its resistance meets the established standards. Otherwise, it is allowed to use an artificial ground electrode. For its construction you need:

Metal for grounding (pipe, smooth fittings, steel angle, rod, tape).

Wire made of steel, copper or aluminum of sufficient cross section.

Mounting material (metal corners, clamps, couplings).

Fixings and insulation made of plastic.

What does modular pin grounding consist of? Source ecoask.ru

The ground loop of a country house can be organized on the basis of the modular pin method. The system is extremely resistant to corrosion, and welding is not used during installation. Pin grounding is assembled from steel rods up to 1.5 m long with a threaded connection. Copper-plated (or with a top layer of stainless steel) pins are driven into the ground with a vibrating hammer (perforator) with a special nozzle. The electrodes (pins) are mounted at a great depth, so the circuit parameters do not depend on seasonal changes. The kit is usually purchased ready-made from the installation company. The high cost of such a circuit is justified by its durability: the service life of copper-plated rods reaches 30 years, of stainless steel - 50 years.

Modular grounding kit Source tirez.ru

black metal outline

This design has a limited service life (5-10 years due to corrosion); over time, the resistance of the circuit deteriorates significantly. It is allowed to use black rolled metal with an anti-corrosion coating, but care must be taken that such a coating is not a dielectric.

Requirements for the resistance of the grounding device.

Grounding for a private house makes sense if the loop resistance is minimal. In this case (when the resistance of a person is much higher than the resistance of the circuit), an imperceptible charge will pass through the body, and the remaining potential will go into the ground.

The resistance is determined by the type, number and depth of the grounding elements, as well as the properties of the soil. Loamy and clayey soils with a moisture content of 20-40% are considered optimal.

To make sure that the grounding device performs its functions, a resistance measurement is carried out.

Video description

How the measurements are carried out - on the video:

What to do when replacing old wiring with TN-C grounding

In most houses of the old housing stock, a two-wire power supply system was installed. Even if grounding was installed, it was carried out according to the TN-C scheme, which uses a single "neutral" conductor to perform two tasks - working (for the operation of electrical appliances and devices) and protective (to save electrical network equipment).

In fact, such a system reliably protects the electrical circuit as a whole, but leaves powered household appliances and their owners with little or no protection. In addition, in wet weather, such a connection can lead to voltage surges even with a protective shutdown - cases of fatal outcomes are known for similar reasons.

PEN conductor separation scheme Source tirez.ru

When building new houses, this system is not allowed; where it has been preserved, it is recommended, if possible, to cross the TN-C-S system (at the entrance to the building, the PEN wire is re-grounded, followed by separation into PE and N). In an emergency, the N conductor is disconnected from the network, saving household electrical appliances and their owners from problems.

Switching to a TN-C-S system in houses with worn-out electrical wiring is justified for safety reasons.

Why is an RCD needed in the presence of grounding

RCD (residual current device) is a high-speed switch that works in tandem with the ground loop and responds to current leakage by breaking the circuit.

Source tirez.ru

Scheme without grounding and RCD

When the insulation of the conductor is broken, the phase appears on the metal case of the electrical device. If the current has nowhere to go further, then when a person contacts the body of an electrical appliance, the discharge will go through the body. The consequences will depend on many factors and the results can be different - from fright to interruptions in the work of the heart.

Without grounding the phase on the surface of the device with damaged wiring will remain until the introductory machine is turned off.

RCD in a circuit without a protective conductor (TN-C)

In such a system, if the insulation of the conductor is broken, the RCD will not immediately work, since no leakage current will occur. But as soon as a person touches a damaged device, part of the current will go into the body and the RCD will work.

Even without grounding current will flow through the human body only for the time necessary for the RCD to trip are usually tenths of a second. As a result, painful sensations are possible, but a fatal outcome is likely to be avoided.

Circuit with protective conductor (TN-S and TN-C-S) and RCD

If the electrical appliance is in contact with the ground loop and is connected through an RCD, then in case of short circuit of the phase conductor on the metal case electrical appliance, immediately leaks current (which goes to the ground). The RCD trips and breaks the circuit.

Gas boiler and RCD

First of all, you need to understand that the grounding of a gas boiler in a private house must be carried out without fail - there are no exceptions.

The grounding of the gas boiler and the installation of the RCD are carried out simultaneously. This is a necessary condition when connecting gas to a residential building, since surface stress forms on the gas boiler body during operation.

Grounding a gas boiler in a private home will avoid damage to expensive electronic equipment and prevent fires caused by static electricity. This measure, given the high explosiveness of the gas, serves as additional protection against fire.

All parts of the gas boiler are grounded without fail Source pinterest.com

What work is carried out during the installation of grounding

The whole process of creating a ground loop is divided into the following stages:

After determining the safe depth of the structure (where the soil is always wet), a trench is dug.

Metal rods (grounding electrodes) are buried in the ground.

A ground loop is assembled: rods arranged in a row or in the shape of a figure (usually a triangle), connected with tape or pipes, welded in series.

The contour is additionally welded to the down conductor with a steel tape.

The finished ground electrode is connected to the electrical panel, the trench is filled up.

When installing, competent specialists take into account some important nuances:

The contour should be located below the freezing line of the soil. Otherwise, when the water in the ground turns into ice, the ground will stop conducting current and grounding will not work.

Grounding electrodes cannot be painted, since the paint layer is a dielectric and there will be no contact between the circuit and the ground.

Grounding in a private house, circuit diagram Source asutpp.ru

Conclusion

Everything that has become familiar in everyday life - a refrigerator, a microwave oven, a hydromassage cabin - should not be dangerous. Properly designed grounding in a country house, when the circuit of the system and the instrument housings are one, should provide a safe power supply, without risk to people and their environment.

The main elements of the scheme for connecting the grounding of a country house and the rules for their implementation

The ground connection diagram in a country house is as follows: electrical appliance - socket - electrical panel - ground conductor - ground loop - ground.

Dependence of the ground connection scheme on the ground loop

Dependence of the connection scheme on the type of grounding system

TN-S earthing system

Figure 1. TN-S system

TN-C earthing system. The need to switch to TN-C-S

Figure 2. TN-S system

Grounding connection according to the TN-C-S system

Let's consider the grounding connection scheme in a country house according to the TN-C-S system using the example of transition to it from the TN-C system.

Figure 3. Schematic of the main switchboard

Figure 4. Earth connection diagram (transition from TN-C to TN-C-S)

Figure 5. TN-C-S ground connection diagram

TT earth connection

Figure 6. TT system

Figure 7. TT earth connection diagram

Figure 8. Connection diagram for grounding and RCD according to the TT system

Conclusion

The grounding scheme in general terms is a connection of its elements: electrical equipment, input distribution board, grounding conductor PE, ground electrode.

To install a grounding device in a country house, you need to understand the features of its connection, depending on the following factors:

method of supplying the electrical network (overhead lines or cable from a transformer substation)
type of soil in the adjacent area where the ground loop is performed.
the presence of a lightning protection system, additional power supplies or specific equipment.

Do you need advice on the organization of grounding and lightning protection for your facility? Contact

home > Tests

How to make grounding in a wooden house. Grounding in a private house: how to do it right with your own hands

What does network grounding mean?

What is the purpose of grounding in a house?

Symbols and designations on the diagrams

Electrical networks and grounding schemes

Network without grounding TN-C

Networks with a separate ground line TN-CS

Network with separate ground loop TN-S

Mains supply with separate earthing TT

How to quickly check the quality of grounding

Ways to create grounding

Results and wishes

The main elements of the scheme for connecting the grounding of a country house and the rules for their implementation

Dependence of the ground connection scheme on the ground loop

Dependence of the connection scheme on the type of grounding system

TN-S earthing system

TN-C earthing system. The need to switch to TN-C-S

Grounding connection according to the TN-C-S system

TT earth connection

Conclusion

Elements and materials

Schemes and dimensions

Location selection

Grounding check

Work sequence

Protective zeroing

Why do you need grounding in a private house: the principle of operation

Video description

Video description

Explanation of abbreviations

TN-C system

TN-S system

TN-C-S system

Circuit elements, grounding options and required materials

black metal outline

Requirements for the resistance of the grounding device.

Video description

What to do when replacing old wiring with TN-C grounding

Why is an RCD needed in the presence of grounding

Scheme without grounding and RCD

RCD in a circuit without a protective conductor (TN-C)

Circuit with protective conductor (TN-S and TN-C-S) and RCD

Gas boiler and RCD

What work is carried out during the installation of grounding

Conclusion

The main elements of the scheme for connecting the grounding of a country house and the rules for their implementation

Dependence of the ground connection scheme on the ground loop

Dependence of the connection scheme on the type of grounding system

TN-S earthing system

TN-C earthing system. The need to switch to TN-C-S

Grounding connection according to the TN-C-S system

TT earth connection

Conclusion

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