What is grounding in simple words. Notation. Grounding work in the private sector

The electrical connection of an object made of conductive material to ground. Grounding consists of a ground electrode (a conductive part or a set of interconnected conductive parts that are in electrical contact with the ground directly or through an intermediate conducting medium) and a grounding conductor connecting the grounded device to the ground electrode. The ground electrode can be a simple metal rod (most often steel, less often copper) or a complex set of specially shaped elements.

The quality of grounding is determined by the value of the electrical resistance of the grounding circuit, which can be reduced by increasing the contact area or the conductivity of the medium - using many rods, increasing the salt content in the ground, etc. In Russia, grounding requirements and its arrangement are regulated.

Protective grounding conductors in all electrical installations, as well as neutral protective conductors in electrical installations with voltages up to 1 kV with a solidly grounded neutral, including busbars, must have the letter designation PE and a color designation with alternating longitudinal or transverse stripes of the same width (for busbars from 15 to 100 mm ) yellow and green colors.

Zero working (neutral) conductors are designated by the letter N and the color blue. Combined neutral protective and neutral working conductors must have the letter designation PEN and a color designation: blue along the entire length and yellow-green stripes at the ends.

Errors in the grounding device

Incorrect PE conductors

Sometimes water pipes or heating pipes are used as a grounding conductor, but they cannot be used as a grounding conductor. There may be non-conductive inserts in the plumbing (such as plastic pipes), electrical contact between pipes may be broken due to corrosion, and finally, part of the pipeline may be disassembled for repairs.

Combining the working zero and PE conductor

Another common violation is the combination of the working zero and the PE conductor beyond the point of their separation (if there is one) along the energy distribution. Such a violation can lead to the appearance of quite significant currents through the PE conductor (which should not be current-carrying in its normal state), as well as to false trips of the residual current device (if installed). Incorrect separation of the PEN conductor

The following method of “creating” a PE conductor is extremely dangerous: a working neutral conductor is identified directly in the socket and a jumper is placed between it and the PE contact of the socket. Thus, the PE conductor of the load connected to this socket is connected to the working zero.

The danger of this scheme is that a phase potential will appear on the grounding contact of the socket, and consequently on the body of the connected device, if any of the following conditions are met:
- Break (disconnection, burnout, etc.) of the neutral conductor in the area between the socket and the shield (and also further, up to the grounding point of the PEN conductor);
- Rearranging the phase and neutral (phase instead of neutral and vice versa) conductors going to this outlet.

Protective function of earthing

The protective effect of grounding is based on two principles:

Reducing the potential difference between a grounded conductive object and other naturally grounded conductive objects to a safe value.

Discharge of leakage current when a grounded conductive object comes into contact with a phase wire. In a properly designed system, the appearance of leakage current leads to immediate operation of protective devices ().

Thus, grounding is most effective only in combination with the use of residual current devices. In this case, with most insulation failures, the potential on grounded objects will not exceed dangerous values. Moreover, the faulty section of the network will be disconnected within a very short time (tenths of hundredths of a second is the response time of the RCD).

Grounding operation during electrical equipment malfunctions A typical case of electrical equipment malfunction is the contact of phase voltage with the metal body of the device due to insulation failure. Depending on what protective measures are implemented, the following options are possible:

The housing is not grounded, there is no RCD (the most dangerous option). The body of the device will be under phase potential and this will not be detected in any way. Touching such a faulty device can be fatal.

The housing is grounded, there is no RCD. If the leakage current along the phase-body-grounding circuit is large enough (exceeds the operating threshold of the fuse protecting this circuit), then the fuse will trip and turn off the circuit. The highest effective voltage (relative to ground) on a grounded case will be Umax=RGIF, where RG? ground resistance, IF ? the current at which the fuse protecting this circuit is triggered. This option is not safe enough, since with a high grounding resistance and large fuse ratings, the potential on the grounded conductor can reach quite significant values. For example, with a ground resistance of 4 ohms and a fuse rated at 25 A, the potential can reach 100 volts.

The housing is not grounded, an RCD is installed. The body of the device will be at phase potential and this will not be detected until there is a path for the leakage current to pass. In the worst case, a leak will occur through the body of a person who touches both a faulty device and a naturally grounded object. The RCD disconnects the faulty section of the network as soon as a leak occurs. A person will receive only a short-term electric shock (0.010.3 seconds - the RCD response time), which, as a rule, does not cause harm to health.

The housing is grounded, the RCD is installed. This is the safest option, since the two protective measures complement each other. When phase voltage hits a grounded conductor, current flows from the phase conductor through the insulation fault into the grounding conductor and further into the ground. The RCD immediately detects this leak, even if it is very insignificant (usually the sensitivity threshold of the RCD is 10 mA or 30 mA), and quickly (0.010.3 seconds) disconnects the section of the network with the fault. In addition, if the leakage current is large enough (exceeds the tripping threshold of the fuse protecting that circuit), then the fuse may also trip. Which protective device (RCD or fuse) will turn off the circuit depends on their speed and leakage current. It is also possible for both devices to be triggered.

Types of grounding

TN-C

The TN-C system (French Terre-Neutre-Combine) was proposed by the German concern AEG (AEG, Allgemeine Elektricitats-Gesellschaft) in 1913. The working neutral and the PE conductor (Protection Earth) in this system are combined into one wire. The biggest drawback was the formation of linear voltage (1.732 times higher than the phase voltage) on the housings of electrical installations during an emergency zero break.

Despite this, today you can find this in buildings in the countries of the former USSR.

TN-S

To replace the conditionally dangerous TN-C system, in the 1930s the TN-S system (French Terre-Neutre-Separe) was developed, in which the working and protective zeros were separated directly at the substation, and the ground electrode was a rather complex structure of metal fittings.

Thus, when the working zero was broken in the middle of the line, the electrical installation housings did not receive line voltage. Later, such a grounding system made it possible to develop differential circuit breakers and current leakage circuit breakers capable of sensing small currents. Their work to this day is based on Kirghoff’s laws, according to which the current flowing through the phase wire must be numerically equal to the current flowing through the operating zero.

You can also observe the TN-C-S system, where the separation of zeros occurs in the middle of the line, however, if the neutral wire breaks before the separation point, the housings will be under line voltage, which will pose a threat to life if touched.

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Every day at home and at work we have to deal with electricity, which makes human life more comfortable. But, despite the benefits that the use of electricity gives us, it still poses a certain danger, for example, electric shock. To avoid this, electrical safety requirements have been developed and special protection measures are being taken. Such measures include grounding and grounding. What is the difference between them and whether there is one, we will figure it out in this article.

All work related to electricity should only be carried out by specialists

The main requirement for household electrical appliances is safety. This applies to a greater extent to devices that come into contact with water, because even a minor defect in the equipment can be fatal to the user. To protect yourself and others, it is necessary to maintain the electrical network and equipment in good condition and regularly inspect them.To eliminate the possibility of a fire due to faulty wiring and electric shock, it is necessary to install protective devices (RCD).

In accordance with the basic electrical safety rules:

This is just a short list of electrical safety requirements. More detailed information about safety rules can be found in various regulations and special literature on electricity, which are now easily found on the Internet.

What is grounding, principle of operation and device

When creating an electrical network in premises for various purposes, it is necessary to create protection that will prevent possible electric shock. To avoid this, a grounding device is installed. In accordance with the PEU clause 1.7.53, grounding is carried out in electrical equipment with a voltage of more than 50 V AC and 120 V DC.

Grounding is the intentional connection of non-current-carrying metal parts of electrical installations (which may be live) with the ground or its equivalent. This protective measure is designed to eliminate the possibility of electric shock to a person due to a short circuit to the equipment body.

Operating principle

The operating principle of protective grounding is:

• reducing the potential difference between the grounded element and other conductive objects with natural grounding to a safe value;
• current drainage in case of direct contact of the grounded equipment with the phase wire. In a well-designed electrical network, the occurrence of a leakage current causes an instantaneous operation of a residual current device (RCD).

From the above it follows that grounding is more effective when used in conjunction with an RCD.

Grounding device

The design of the grounding system consists of a ground electrode (the conductive part that has direct contact with the ground) and a conductor that provides contact between the ground electrode and non-current-carrying elements of electrical equipment. Typically, a steel or copper (very rarely) rod is used as a grounding conductor; in industry, this is usually a complex system consisting of several specially shaped elements.

The effectiveness of the grounding system is largely determined by the resistance value of the protective device, which can be reduced by increasing the useful area of ​​the ground electrodes or increasing the conductivity of the medium, for which several rods are used, the level of salts in the ground increases, etc.

The grounding device is...

Above we examined in general terms what protective grounding is. However, it is worth mentioning that the grounding conductors used in the system differ in natural and artificial.

As grounding devices, it is primarily preferable to use such natural grounding devices as:

Important! It is prohibited to use pipelines with gas and flammable liquids, as well as heating mains as a grounding element.

Natural grounding conductors must be connected to the protective system from two or more different points.

The following can be used as an artificial grounding device:

• steel pipe with a wall thickness of 3.5 mm and a diameter of 30÷50 mm and a length of about 2÷3 m;
• steel strips and corners with a thickness of 4 mm;
• steel rods up to 10 or more meters long and with a diameter of 10 mm.

For aggressive soils, it is necessary to use artificial grounding conductors with high corrosion resistance and made of copper, galvanized or copper-plated metal.So, we have figured out what is the definition of the concept of artificial and natural grounding, now we will look at when grounding is used.

This video clearly explains what protective grounding is:

When and where is grounding applied?

As already mentioned, protective grounding is intended to eliminate the possibility of electric shock to people in the event of voltage being applied to conductive parts of the equipment, that is, in the event of a short circuit to the housing.Protective grounding is used to equip metal non-current-carrying elements of electrical installations, which, due to a possible breakdown of wire insulation, may become energized and cause harm to the health and life of people and animals if they come into direct contact with faulty equipment.

Electrical networks and equipment with voltages up to 1000 V are subject to grounding, namely:

• alternating current;
• three-phase with isolated neutral;
• two-phase, isolated from ground;
• direct current;
• current sources with an isolated winding point.

Grounding is also necessary for electrical networks and electrical installations of direct and alternating current with voltages over 1000 V with any neutral or midpoint of the current source winding.

Basic methods of grounding

When constructing a grounding system, vertical metal rods are usually used as a grounding conductor. This is due to the fact that horizontal electrodes, due to their shallow depth, have increased electrical resistance. Steel pipes, rods, angles and other rolled metal products with a length exceeding 1 meter and having a relatively small cross-section are almost always used as vertical electrodes.

There are two main methods for installing vertical ground electrodes.

Related article:

Electricity can not only create comfortable living conditions, but also carries a certain danger. To reduce the likelihood of this hazard occurring, it is necessary DIY grounding in a private house 220V. How to make it - read the publication.

Several short electrodes

This option uses several steel angles or rods 2-3 meters long, which are connected together using a metal strip and welding. The connection is made at the surface of the earth.Installation of the ground electrode occurs by simply driving the electrode into the ground using a sledgehammer. This method is better known as “corner and sledgehammer”.

The minimum permitted cross-section of grounding electrodes is given in the PUE, but most often the corrected and supplemented values ​​are from technical circular No. 11 of RusElectroMontazh. In particular:

The advantages of this method are simplicity, low cost and availability of materials and installation.

Single electrode

In this case, an electrode in the form of a steel pipe (usually single) is used as a grounding electrode, which is placed in a deep hole drilled in the ground. Drilling the soil and installing the electrode requires the use of special equipment.

An increase in the contact area of ​​the ground electrode with the ground is ensured by a greater depth of installation of the electrode. Moreover, this method is more effective in comparison with the previous option, with the same total length of the electrodes, due to reaching deep layers of soil, which usually have low electrical resistivity.

The advantages of this method include high efficiency, compactness and seasonal “independence”, i.e. Due to winter freezing of the soil, the resistivity of the ground electrode practically does not change.

Another way is to lay a grounding conductor in a trench. However, this option requires greater physical and material costs (more material, digging a trench, etc.).

Having figured out how grounding works and why it is needed, we now face the second question of our article, namely, what constitutes grounding, why it is needed and how it differs from grounding.

What is zeroing

The term grounding refers to the intentional connection of open non-current-carrying conductive parts of the electrical network and equipment with a solidly grounded point in single- and three-phase DC and AC networks. Grounding is performed for electrical safety purposes and is the main protective measure against voltage.

Operating principle

A short circuit in the electrical network occurs when an energized phase wire comes into contact with the body of the device connected to zero. The current increases sharply, and protective devices are activated, cutting off power from the faulty equipment. According to the rules, the response time of the RCD to disconnect a faulty electrical network should not exceed 0.4 seconds. To do this, it is necessary that the phase and zero have an insignificant resistance value.

Related article:

Have you ever heard the acronym, you will find out by reading the review to the end. Briefly, I would like to add that this device can protect housing and all its inhabitants from emergency situations related to electricity.

To create a grounding in a single-phase network, as a rule, the third (unused) wire of a three-core cable is used. To create good protection, it is necessary to ensure a high-quality connection of all elements of the grounding system.

Device

The grounding system, for example, in an apartment building, begins with a grounded power transformer, from which the neutral with a three-phase line comes to the main distribution board (MSB) of the building. What happens next. A working zero is created from the neutral, which, together with the phase wire, forms the usual single-phase voltage.

The grounding itself to protect the electrical network and equipment is created in the panel using a conductor connected to a grounded neutral. You should know that it is forbidden to install switching devices (automatic machines, packets, switches, etc.) between zero and neutral.

Where is the zeroing scheme used?

According to the requirements of the PES, the following must be equipped with protective grounding:

• single- and three-phase AC networks with a grounded terminal and voltage up to 1,000 V;
• DC power networks with a central grounding point and voltage up to 1,000 V.

Grounding cannot protect against electric shock like grounding. This protective circuit simply cuts off the voltage supply in the event of a short circuit and turns off the local power grid.

Is it possible to ground in an apartment using grounding?

We already know what grounding and grounding are, and we’ll try to find out whether it’s possible to do grounding using a grounded zero located in the electrical panel. The fact is that many people far from electrical engineering ask this question and often make unforgivable mistakes by doing just that.

Firstly, this is prohibited by PEU. The fact is that if, for example, during installation work, for some reason the phase and zero are mixed up, and besides, the zero is brought to the working zero, then you can expect the most unpleasant situations. When electrical equipment is connected to the network, the housing will be energized and a person will be shocked by an electric shock, since the protective operation of the RCD will not occur.

To create a protective grounding in the floor electrical panel, a separate bus is allocated, connecting to a solidly grounded neutral. And it is best not to carry out this work yourself, but to entrust it to a specialist who has knowledge in electrical engineering.

The video shows how to create a grounding if it is not in the floor electrical panel:

What is the difference between grounding and grounding?

It’s worth saying right away that despite the fact that grounding and grounding are protective measures, they differ in their principle of operation and purpose.Grounding is a more effective and reliable method of protection than grounding, since it allows you to quickly equalize the difference between potentials to the required value. Also, grounding has a simpler design and is easier to install, and to install it you just need to follow the instructions. In addition, this protective circuit does not depend on the phase pattern of the connected equipment. Grounding options are varied, and this allows you to choose a specific type for each specific case

Protective grounding is a protective measure that, in the event of a network malfunction, simply ensures an instantaneous interruption of the supply of voltage from the electrical network by triggering an RCD. Creating grounding and connecting equipment requires experience and certain knowledge in electrical engineering. All installation work, especially determining the zero point, must be performed correctly, otherwise, in an emergency, electric shock may occur.

Having figured out what grounding and grounding are, many people prefer to use both methods. However, grounding is mandatory when installing household and industrial networks, as well as operating equipment.

To better understand the difference between grounding and zeroing, we suggest watching this video:

Requirements for grounding and grounding

Grounding is a more serious protective measure than grounding. This scheme requires the creation of a separate low-resistance busbar, which is connected to a ground electrode buried in the ground and arranged in accordance with the standards. All requirements for grounding, its elements and arrangement are specified in the PEU and GOST 12.2.007.0.

In the industrial sector the following must be grounded:

• electric drives;
• electrical equipment housings;
• metal structures of buildings;
• shielded braiding of low-voltage electrical cables;
• housings of electrical distribution panels and similar structures.

More flexible requirements are imposed on zeroing, namely:

• neutral and phase conductors are selected in such a way that, in the event of a breakdown, a current sufficient to trigger an RCD or other protective mechanism appears on the equipment body;
• The grounding conductor from the device to the grounded neutral must be continuous, that is, it must not contain any switching devices in the circuit.

Let's sum it up

Ensuring the safety of life and health is the primary task of the state, society and, naturally, the individual himself. To do this, you must strictly adhere to the established rules, instructions and requirements. One of the factors dangerous to human health is electricity, so it is very important to ensure sufficient electrical safety at work and at home using certain measures and protective technical means.

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Protective grounding is a system designed to prevent the effects of electric current on a person by deliberately connecting the housing and non-current-carrying parts of equipment that may be energized to ground. Grounding systems can be natural or artificial.

What is grounding and why is it needed?

Grounding devices are a deliberate connection of various points of the electrical network by electrical conductors.

The purpose of grounding is to prevent exposure to electric current to a person. Another purpose of protective grounding is to remove voltage from the electrical installation body through a grounding device to the ground.

The main purpose of using grounding is to reduce the potential level between the point that is grounded and the ground. This reduces the current strength to the lowest level and reduces the number of damaging factors in contact with parts of electrical appliances and installations in which a breakdown has occurred on the housing.

What is neutral?

Neutral is a neutral protective conductor that connects the neutrals of electrical installations in three-phase electric networks. Area of ​​use: grounding of electrical installations.

The step-down substation, where the transformer installation is located, is equipped with its own ground loop. This circuit consists of a steel tire and rods buried in a special way in the ground. A cable with 4 cores is laid to the consumption sources in the electrical panel from the substation. When an electricity consumer needs power from a three-phase circuit, all 4 wires must be connected. When different loads are connected to the conductors, a neutral shift occurs in the system; to prevent this shift, a neutral conductor is used. It helps to symmetrically distribute the load across all phases.

What are PE and PEN conductors?

A PEN conductor is a conductor that combines the functions of a neutral protective conductor and a neutral working conductor. It comes from the substation and is divided into PE and N conductors, directly at the consumer.

The PE conductor is a protective grounding that we use, for example, in an apartment in a grounded outlet. The PE conductor is used for grounding devices, installations and instruments where the voltage level does not exceed 1 kV.

This type of grounding is used only to ensure safety. This grounding ensures continuous connection of all exposed and external parts. The mechanism ensures that current flows to the ground, which appears as a result of electric current entering the body of a device.

The PEN conductor (combination of the neutral protective and neutral working conductor) is used when using a TN-C type grounding system.

Types of artificial grounding systems

In the classification of grounding systems there are natural and artificial types of grounding.

Artificial grounding systems:

• TN-S;
• TN-C;
• TNC-S;

Types of grounding - explanation of the name:

• T -- grounding;
• N - connecting the conductor to the neutral;
• I - insulation;
• C -- combination of functional and neutral wire options;
• S - separate use of wires.

Many people are interested in the question of what is called working grounding. In another way it is called functional. The answer to this question is given by paragraph 1.7.30 of the PUE. This is the grounding of points of live parts of an electrical installation. It is used to ensure the functioning of electrical devices or installations, and not for protective purposes.

Also, many are concerned about the question of what protective grounding is. This is the process of grounding devices to ensure electrical safety.

Systems with solidly grounded neutral TN grounding system

Such systems include:

• TN-C;
• TN-S;
• TNC-S;

According to clause 1.7.3 of the PUE, a TN system is a system in which the neutral of the power source is solidly grounded, and the open conductive parts of the electrical installation are connected to the solidly grounded neutral of the source through neutral protective conductors.

TN includes elements such as:

• grounding electrode of the middle point, which relates to the power source;
• external conductive parts of the device;
• neutral type conductor;
• combined conductors.

The source neutral is solidly grounded, and the external conductors of the installation are connected to the solidly grounded midpoint of the source using protective type conductors.

It is possible to make a grounding loop only in electrical installations whose power does not exceed 1 kV.

TN-C system

In this system, the neutral protective and neutral working conductors are combined into one PEN conductor. They are combined throughout the system. The full name is Terre-Neutre-Combine.

Among the advantages of TN-C, one can highlight only the easy installation of the system, which does not require much effort and money. Installation does not require improvement of already installed cable and overhead power lines, which have only 4 conducting devices.

Flaws:

• the likelihood of receiving an electric shock increases;
• it is possible that line voltage may appear on the body of the electrical installation during an electrical circuit break;
• high probability of loss of the grounding circuit in case of damage to the conductive device;
• This system only protects against short circuits.

TN-S system

The peculiarity of the system is that electricity is supplied to consumers through 5 conductors in a three-phase network and through 3 conductors in a single-phase network.

In total, 5 conductive sources leave the network, 3 of which serve as the power phase, and the remaining 2 are neutral conductors connected to the zero point.

Design:

1. PN is a neutral mechanism that is involved in the circuit of electrical equipment.
2. PE is a solidly grounded conductor that performs a protective function.

Advantages:

• ease of installation;
• low cost of purchasing and maintaining the system;
• high degree of electrical safety;
• no contour creation required;
• the ability to use the system as a current leakage protection device.

System TN-C-S

The TN-C-S system involves dividing the PEN conductor into PE and N in some part of the circuit. Usually the separation occurs in the panel in the house, and before that they are combined.

Advantages:

• simple design of a protective mechanism against lightning strikes;
• availability of short circuit protection.

Disadvantages of use:

• poor level of protection against burning of the neutral conductor;
• possibility of phase voltage occurrence;
• high cost of installation and maintenance;
• the voltage cannot be turned off automatically;
• There is no protection against current in the open air.

TT system

TT is designed to provide a high level of safety. Installed in power plants with a low level of technical condition, for example, where bare wires are used, electrical installations that are located in the open air or mounted on supports.

TT is mounted according to a four-conductor circuit:

• The 3 phases supplying voltage are shifted at an angle of 120° to each other;
• 1 common zero performs the combined functions of a working and protective conductor.

TT advantages:

• high level of resistance to deformation of the wire leading to the consumer;
• short circuit protection;
• Possibility of use on high voltage electrical installations.

Flaws:

• complex lightning protection device;
• inability to track the phases of a short circuit in an electrical circuit.

Isolated Neutral Systems

During the transmission and distribution of electric current to consumers, a three-phase system is used. This makes it possible to ensure symmetry and uniform distribution of current load.

Such a device creates a mode that involves the use of a transformer booth and generators. Their neutral points are not equipped with a ground loop.

The isolated type of neutral is used in the power circuit when connecting the secondary windings of transformer installations in a delta diagram and in the absence of power during emergency situations. Such a network is a replacement circuit.

The insulated neutral contributes to the penetration of the insulating coating during a short circuit and the occurrence of a short circuit in other phases.

IT system

The IT system with voltages up to 1000 V provides grounding through a high resistance level and is equipped with a power supply neutral.

All external elements of the electrical installation, which are made of materials that conduct current, are grounded. Among the advantages are low rates of current leakage during a single-phase short circuit of the electrical network. An installation with such a mechanism can function for a long time even in emergency situations. There is no difference between the potentials.

Disadvantage: Current protection does not operate during a ground fault. When operating in single-phase short circuit mode, the likelihood of electric shock increases when touching the second phase of the installation.

13.07.2018

What is grounding in simple words and why is it needed?

Some manufacturers write in the operating manual for their equipment that in order to operate the equipment it is necessary to ground it.

Grounding installation is also required when building a house. What is grounding, why is it needed, and is it possible to do without it, read below.

What is grounding

Grounding is a method of transferring electrical or electrostatic charge to the ground or into a special charge-nullifying device. In most houses and apartments, electrical wiring is single-phase (alternating current), that is, it consists of a positive and negative charge.

This means that during a power surge it will change direction. As a result, the charge will transfer to the equipment and not leave the system. You will get an electric shock if you touch any electrical appliance connected to the network. At the same time, there is a high probability of failure of all equipment in the house connected to the electrical network.

Essentially, a ground is a metal plate or wire that is used to drain “extra” electricity away from your home to a place where it won’t harm anyone. Grounding conductors also include lightning rods.

Unlike simple grounding, a lightning rod must be installed on tall towers and poles, as such objects experience very strong electrostatic effects, which makes them very attractive to lightning.

How to make grounding yourself

Grounding must be done during the construction phase. This mandatory rule is written in GOSTs and SNiP and PUE. Typically, the grounding function is performed by the iron frame of reinforced concrete blocks. But if other materials are used when constructing the foundation, then grounding will have to be done separately. To do this, dig a trench from the place where the shield is installed.

A wire or metal plate of thickness is laid in the trench not less than 6 mm. Then thick reinforcing rods, 1-1.5 meters high, are driven into the trench at a distance of 80-70 cm from each other. They are connected to each other by plates that are either screwed or welded to them.

The plates and distribution panel are secured with copper wire. The rods should protrude 10-15 cm from the ground. The plate is connected to the busbar on the distribution panel using a copper cable and bolts.

The straight design can be used, but it has one drawback. In the event of a breakdown in the electrical system at home, the pins will be under high voltage and if you touch them, there will be a strong electric shock. Therefore, a triangular type of grounding with a tap is most often used. It allows you to take the ground electrode to another place and protect it.

Triangle welded from plates welded to thick reinforcing bars and a discharge plate, which is placed in a trench dug in advance for this purpose. The outlet plate is connected to the distribution panel in the same way as with a direct ground electrode. There are other grounding schemes, but they are not much different from the previous two.

What happens if you don't ground?

Grounding work requires considerable physical effort and time. The question naturally arises, why so much effort? What are the consequences if you do not carry out grounding work, how dangerous is it to strain yourself like that?

Many people do not ground their homes or apartments for one simple reason. Breakdowns in electrical wiring are a rare occurrence. Even if it happened, for the current to flow strongly, the breakdown must be very large. And so, a slight tingling electric current has never killed anyone, especially if a person does not come into contact directly or through a conductor with the ground, then the electric current is also not felt.

Also, the risk of failure of household electrical appliances is not so great.

By and large, grounding is more likely technical standard requirement, not necessity. In many old houses there is simply no grounding, and no one has ever been electrocuted in such houses. The grounding requirement is most often a requirement of manufacturers of household electrical appliances, especially those made of metal rather than plastic.

How to determine whether there is grounding in a house

If it is not possible to visually determine whether there is grounding in a house or apartment, that is, neither the connection to the grounding system nor the grounding pins are visible anywhere, then you can check it in several ways.

The first one is use special equipment. However, you need to know how to use it, and besides, it costs a lot of money. But there is another way to check whether there is grounding in the house, but it only works if there is a breakdown in the system, which is very important.

It is done like this: take the phone in one hand, make sure it works. And place the other one on a heating radiator or any other metal object. The main thing is that you stand barefoot on the floor. If you feel light tingling from electricity- this means there is no grounding in the house.

Electricity is man's best friend and worst enemy. Of course, now it’s almost impossible to imagine life without him. Unfortunately, there were some bad moments, such as electric shock. You can get an electric shock if you touch not only an exposed live part, but also the seemingly harmless body of an electrical appliance. In this article we will try to explain in simple terms what grounding is and what it is intended for. In addition, we will look at what a difavtomat and RCD are and what they are used for.

Definition of the concept

To put it briefly and in simple words:

Grounding is a device that protects a person from electric shock if all electrical equipment is connected to ground. In an emergency situation, dangerous voltage “drains” to the ground.

Protection is the main purpose of grounding. It consists of connecting an additional, third grounding conductor to the wiring, which is connected to a device such as a ground electrode. He, in turn, has good contact with the ground.

Grounding can be operational or protective according to its intended purpose. The working one is needed for the normal functioning of the electrical installation, the protective one is needed to ensure electrical safety (preventing electric shock).

Typically, grounding (ground electrode) looks like three electrical rods driven into the ground, at equal distances from each other, located in the corners of an equilateral triangle. These rods are connected to each other by a metal strip. You might have seen such rods near houses and buildings.

You may also have noticed that on the walls of many buildings, inside or outside, metal strips are fixed, sometimes painted with yellow and green alternating stripes - this is also connected to the ground electrode. A grounding bus is needed so as not to pull a grounding wire from each electrical installation.

The third conductor is usually connected to the frame of electrical devices, providing protection against dangerous voltage. In cables, it usually has a smaller cross-section than the adjacent “working” conductors and a different insulation color – yellow-green.

Grounding Requirements

The requirements for the protective ground loop are as follows:

1. All electrical installations must be grounded, including metal doors of electrical cabinets and switchboards.
2. The resistance of the grounding device should not exceed 4 Ohms in electrical installations with a grounding neutral.
3. Nessesary to use .

We have figured out what grounding is, now let’s talk about why it is needed.

Why does a person get electrocuted?

Let's consider two typical situations when you are shocked:

1. The washing machine was doing its job properly, and when you wanted to turn it off, you felt that its body was “pinching” you. Or even worse, when you touched it, you got a serious jolt.
2. You decided to take a bath, turned on the water, grabbed the tap, and you felt the same effect of electricity - a tingling or strong blow.

Both situations can be solved by connecting grounding to the housings of appliances and all metal parts in the bathroom and installing an RCD or differential circuit breaker at the input of electricity to a house or a group of consumers.

How does grounding work?

First, let's figure out why dangerous voltage appeared on the body of the washing machine or other electrical equipment. Everything is quite simple - the insulation of the conductors for some reason has deteriorated or been damaged and the damaged area touches the metal casing of some equipment part.

If there is no grounding or grounding of electrical equipment, then when a person touches a damaged device, a potential difference on the surface between the points of contact may occur. When standing near damaged equipment, a (potential difference between feet touching the ground) may occur. Touch voltage and step voltage can be dangerous to humans. To reduce their value to a safe value, protective grounding is used.

Even such small values ​​as 50 mA are dangerous for humans - such a current can lead to ventricular fibrillation and death.

So, the principle of grounding is as follows: the housings of all electrical appliances are connected to the ground electrode, and an RCD is additionally installed. If a dangerous voltage occurs on the frame, the ground always attracts the dangerous potential to the safe ground potential and the voltage “drains” to the ground.

What are RCDs and difavtomats used for?

Simply grounding devices is good, but providing additional protection is even better. For this they came up with (RCD) and.

A difavtomat is a device that combines an RCD and a conventional circuit breaker in its housing, so you will save space in the electrical panel.

RCD - reacts only to . The principle of its operation is this: it compares the amount of current through the phase and through the neutral wire; if part of the current has flowed to the ground, then it instantly reacts by turning off the circuit. They are distinguished by sensitivity from 10 to 500 mA. The more sensitive the RCD, the more often it will trigger, even with minor leaks, but you should not install an RCD that is too rough for your home.

The principle of operation of a protected circuit in simple terms:

When a phase hits the housing of grounded electrical equipment, current begins to flow between the phase wire and the housing. Then the RCD notices that current has flowed through the phase wire, some of the current has been sent somewhere, and a smaller current has returned through the neutral wire, after which this circuit is de-energized. This way you are protected from electric shock.

If you install an RCD in a two-wire electrical circuit without a grounding conductor and there is a possibility of current leakage somewhere, it will only work after you touch this place and the current flows to the ground through you. In this case, you will also be safe.

That's all we wanted to tell you regarding this issue. Now you know what grounding is, when and how it is installed and what it is used for. We hope the information was presented clearly and accessible to you!