Modern appliances, equipment and household appliances that consume electrical energy require certain safety measures when handling them. One of these activities is grounding in the apartment. This system is very similar to, but differs significantly in the principle of its action.

Basic concepts of zeroing

In the absence and impossibility of its equipment, zeroing is used. However, this type of protection does not directly protect against the effects of electric current. When touching live parts, it is grounding that provides the necessary safety. Zeroing differs from grounding by the rapid action of protective equipment. That is, when touching a dangerous place, a circuit breaker is triggered, turning off the electric current.

To ensure the desired effect, the grounding conductor is connected to the body of a device and the neutral neutral wire of the electrical network. Such a scheme will be called zeroing. Thus, the neutral wire performs not only its main function, but also provides the necessary protection.

However, zeroing does not always guarantee a high level of safety. In the event of a break in the neutral wire for any reason, all devices in the apartment connected to the network will have a phase instead of zero on their case. This situation poses a serious danger to human life and health. Sometimes accidents occur as a result of a tangle of wires, when a phase can be connected instead of zero. The maximum effect from the use of zeroing can be obtained by knowing well the principle of its operation.

How nulling works

If any device or equipment connected to the neutral wire gets on the case, a short circuit occurs. In a damaged circuit, a circuit breaker trips, cutting off the electrical current. In addition, electricity can be turned off with a fuse. The shutdown time for each case is regulated by the PUE. For example, at a nominal phase voltage of an electrical network of 220 or 380 volts, it does not exceed 0.4 seconds.

For the grounding device, special conductors are used. In a single-phase network, this is usually the third core of a cable or wire. These conductors are subject to increased requirements. Their resistance must be small so that the protective equipment can operate within a set period of time. In the case of high resistance, the machines very often do not work. Because of this, the probability increases sharply in case of contact with the body of the equipment or device. Therefore, very strict requirements are set for the quality of installation and connections of such sections. Breaks must not be made in these conductors in order to connect circuit breakers or fuses. Failure to comply with these rules will lead to the fact that zeroing in the apartment will give a low effect.

Zeroing provides not only a quick disconnection of the device from the network. With its help, the minimum voltage is set at which operation occurs in the event of a touch. As a result, electrical safety is significantly increased.

In the absence of grounding in the apartment, protective grounding for sockets in practice is carried out as follows. The main neutral wire located in the electrical panel is divided into two components. They consist of a zero working and protective conductor. The protective conductor is brought to the socket and connected to the ground contact available in it. Thus, additional security is provided.

For safe operation on various electrical installations and conductors, open metal taps are connected to the ground and the network is connected to the neutral cable. But few novice masters know exactly how grounding and grounding of electrical installations and electrical equipment differ.

Grounding Definition

Grounding is the intentional connection of exposed parts of electrical equipment that are energized to a special ground outlet, bus bar or other protective equipment. This may be fittings in the ground, part of an electrical installation and other devices. Such an approach, according to the PUE, is a mandatory measure for the deliberate protection of both residential and non-residential stock. This is also stated by the rules and requirements of GOST 12.1.030-81 SSBT (electrical safety and the system of labor safety standards).

Photo - diagram

Almost every modern house has a TN-C-S or TN-S grounding scheme. But in buildings of an old building, grounding is often absent at all, so the owners of an apartment in such buildings have to organize the land on their own. Such a system is called TN-C. It is carried out by connecting the tap to the ground loop, which can be located directly in the ground near the building or near the transformer box.

Figure TN-C

Theoretically, a special installation company can organize such a wiring upgrade, but this is rarely practiced. More often, earth is brought to the shield on the floor (in an apartment building), and the rest of the wires are already connected to it.

1. If a phase hits an open metal outlet of any electrical device, then voltage appears in it. The same happens if, for example, the cable insulation is broken. The human body is an excellent conductor of current, if you touch such a tap, you will receive a strong electric shock. Grounding will help avoid this;
2. Stray currents go to the grounding conductor, this guarantees the protection of life;
3. Especially dangerous is the voltage that falls on heating radiators. In this case, all the batteries in the house become current conductors. But if the ground is installed, then all the voltage will go through the conductor.

Photo - land option

If it is not possible to conduct a full-fledged ground loop, then other methods are used. For example, it is now very common to connect portable grounding pins (portable tires). Their action does not differ in any way from a standard stationary outlet, but at the same time they are much more practical in terms of their functionality.

Photo - portable tire

Purpose of zeroing

Sometimes zeroing and grounding are confused with each other, so what is the difference between them? Zeroing is used according to the PUE only for industrial installations and is not a guarantee of safety. If the phase falls on the open part of the device, then the current does not go away. After that, the pairing of two phases occurs, and, as a result, a short circuit. The neutral conductor is necessary for the quick response of the differential circuit breaker to a short circuit, but not for protecting a person from electric shock. Therefore, it is customary to use it only in production, where a quick power off is required in the event of an emergency.

Photo - grounding scheme

Do I need to do zeroing in a private house or apartment? No, this is not necessary, and even fraught with various negative consequences. Let's say if the neutral wire burns out, then more of the electrical devices to which it was connected will break due to an extremely high voltage surge. It is worth remembering that your safety will not be affected if, along with grounding, you also equip grounding, install an RCD and a protective switch.

Photo - the principle of operation of zeroing

How to set zeroing so that the device connected to it does not burn out:

1. A three-core insulated wire must be used. One core is reserved for phase, the second for zero, the third for grounding;
2. The earth is connected at the very end of electrical work to the body of a safe conductor to the ground loop, etc. The most practical is a special ground tap at the shield;
3. For safety reasons, various power switches and other protective installations must be installed.

Video: what is the difference between zeroing and grounding

Main difference

The most important thing to remember is that grounding and grounding circuits have different protective effects. Zero guarantees a fast response to potential changes or current leakage for protection installations. Accordingly, at high voltage, all energy consumers are turned off: lighting fixtures, computers and other machines (including machine tools, transformers).

Photo - difference between zeroing and grounding

Grounding provides equalization of potentials and protection against electric shock. Earth is more often used at home, its installation can be easily done by hand. But there is no guarantee that the fuses will respond quickly to a leak. The best option to increase the safety guarantee is the joint use of grounding and grounding of networks and open parts of machines.

Before installing any of these protection options, it is imperative to obtain a work permit. In addition, a protective conductor is calculated, the land is connected to each consumer in the dwelling, and protective equipment is installed.

Zeroing is the intentional electrical connection of a dead-earthed neutral point of a transformer or generator in single-phase networks, with open conductive surfaces of electrical installations and equipment that are not energized in a normal state.

Grounding is performed to ensure the electrical safety of electrical equipment in industrial production.

In everyday life, according to the new PUE standards specified in 1.7.132, this method of electrical protection is prohibited.

The home electrical network is single-phase, since household electrical appliances are powered from ordinary sockets, where there is a phase and a working zero, which must not be combined with a protective wire, making the case zero.

Application in production

Zeroing is used for a guaranteed fast time (no more than 0.4 s) for the operation of protective switches and fuses in production, if a life-threatening voltage appears on the case.

The difference between grounding and zeroing

At the same time, fire safety is also ensured - if grounding alone is used, due to its greater resistance than that of the zero wire, the leakage current may not be sufficient to quickly open fuses designed for high load currents.

Protective grounding scheme. 1) Electrical installation; 2) Explorer; 3) Ground electrodes.

But, these values ​​of the leakage current, and the period of time required for the operation of the protection, may be enough for the insulation of the wires inside the equipment to catch fire and cause a fire.

Thus, with the help of zeroing, a short-term short-circuit current is guaranteed to be achieved, which does not have time to heat up the wiring, but causes the protective devices to work. It must be understood that in this case, grounding and grounding are used together, since the equipment is grounded by a common enterprise that has many grounding devices.

Protective grounding scheme. 1) Electrical installation; 2) Current protection; Ro - grounded neutral wire

In addition, electricity is supplied to production from several inputs, which guarantees phase balance and insures the system against a zero break.

Unauthorized zeroing is deadly!

Often, when upgrading the old electrical wiring in an apartment, with the transition to a new, three-wire system, with a PE protective wire, some “unfortunate experts” say that grounding is zeroing, and they advise to zero the PE bus if the old TN-C system is operated in an apartment building .

This advice is deadly for a number of reasons:

progress in electrical engineering

Previously, zeroing was actively used in everyday life for the electrical safety of electric stoves. But in such houses, increased attention was paid to the neutral wire, in each floor panel there was a re-grounding, so grounding was not dangerous due to. Power supply in those days was carried out through the TN-C system, where the neutral wire simultaneously served as a protective conductor.

TN-C earthing system

The electrical installation of equipment and electrical installations was regulated by the standards of the Electrical Installation Code of the sixth edition, where it was generally forbidden to operate electrical equipment without grounding.

But progress in electrical engineering led to the fact that the old system was abolished due to many shortcomings, some of which were described above.

TN-S earthing system

At the moment, new standards for the seventh edition of the PUE are in force, which require that the power supply of residential buildings and organizations be carried out using the new TN-S, TN-C-S systems.

Earthing system TN-C-S

The use of zeroing in power supply

According to the new PUE standards, in the TN-C-S power supply system, grounding replaces the grounding regarding household electrical appliances, but does not exclude it from the protective process on a global scale, since the grounding of the PE protective wire bus occurs at the input distribution device (ASU) of an apartment building.

In this case, the combined PEN wire is connected to the main ground bus (GZSH), which has a re-ground.

Although zero is attached directly to the GZSH, which is also a PE bus that has contact with metal cases of household electrical appliances through a protective conductor, such grounding differs from simply connecting the PEN neutral wire to the ground terminal of electrical equipment in the apartment.

The difference is that in this case, the ASU is re-grounding the neutral wire, which can theoretically be considered as grounding the grounding device and the PE bus connected to it. But it is not customary to say this, this process is called the separation of the PEN wire into PE (protective conductor) and N (working zero) at the re-grounding point.

Zeroing alternative

In the TN-S system, the grounding of the PE protective wire occurs only at one point - at a transformer substation or generator, where the PEN wire is separated, and after it the protective conductor and the working zero do not intersect anywhere.

In the power supply schemes described above, grounding and neutraling complement each other, providing electrical safety, but in systems with isolated neutral (IT), as well as in the TT system, neutraling is not used at all.

Electrical equipment receiving power supply according to the IT or TT regulations is grounded using its own circuits. Since specific equipment is powered in IT mode, it is worth considering only the TT system in more detail, as the only alternative to unauthorized and incorrect grounding of the PE bus, because the transition to new power supply systems (TN-S, TN-C-S) is a big problem for many older houses. twenty years old.

The electrical network, made according to the TT scheme, will be able to reliably provide electrical protection against damage, and will be much safer than unauthorized zeroing, if it complies with the PUE 1.7.39 standard.

When modernizing home electrical wiring, this method of ensuring safety is more reliable than nulling the PE bus, or leaving it not connected at all, waiting for the power grid of the entire apartment building to be updated.

Zeroing in a private house

It is not forbidden to separate the PEN in a private house if the following PUE standards are met:

In this case, for the combined neutral wire, re-grounding plus zeroing is performed for the PE protective conductor bus.

Based on the foregoing, we can conclude that a properly performed zeroing is an important link for ensuring electrical safety, and together with grounding, it makes it possible to supply power using a cheaper TN-C-S system.

TT system

The difference in price, compared to TN-S, is that the PEN is separated at the entrance to the house, and there is no need to pull the PE wire to the transformer substation. But you also need to remember that ignoring the regulations and prohibitions of the PUE can lead to fatal consequences if you arbitrarily zero the PE conductor or metal cases of the equipment. AT

All independent electrical work must be agreed with the power supply company, and they must also make control measurements and check the correctness of the work.

Introduction

Protective grounding, (zeroing), is the main measure for protecting metal structures. The main purpose of this measure is to protect against a possible electric shock to the user of the device in case of a short circuit to the case, for example, electric shock in the event of a phase wire shorting to when the insulation is broken. In other words, grounding is a substitute for the protective functions of fuses. There is no need to ground all electrical appliances in the house: most of them have a reliable plastic case, which itself protects against electric shock. Protective grounding differs from grounding in that the bodies of machines and apparatuses are connected not to "ground", but to a grounded neutral wire coming from a transformer substation along a four-wire power line. To ensure complete human safety, the resistance of grounding conductors (together with the circuit) should not exceed 4 ohms. For this purpose, twice a year (in winter and summer) they are checked by a special laboratory.

Grounding - a deliberate electrical connection of any point of the electrical network, electrical installation or equipment, with a grounding device.

The grounding device consists of a grounding conductor (a conductive part or a set of interconnected conductive parts that are in electrical contact with the ground directly or through an intermediate conductive medium) and a grounding conductor connecting the grounded part (point) to the grounding conductor. The grounding conductor can be a simple metal rod (most often steel, less often copper) or a complex set of special-shaped elements. The quality of grounding is determined by the value of the resistance of the grounding device, which can be reduced by increasing the area of ​​the grounding conductors or the conductivity of the medium - using many rods, increasing the salt content in the ground, etc. The electrical resistance of the grounding device is determined by the requirements of the PUE

Terminology

Solidly grounded neutral - the neutral of a transformer or generator, connected directly to the grounding device. The output of a single-phase AC source or the pole of a DC source in two-wire networks, as well as the midpoint in three-wire DC networks, can also be solidly grounded.

Isolated neutral - the neutral of a transformer or generator that is not connected to a grounding device or connected to it through a high resistance of signaling, measuring, protection devices and other similar devices.

Notation

Designation on the diagrams (two symbols on the right)

Protective earth conductors in all electrical installations, as well as zero protective conductors in electrical installations with voltages up to 1 kV with a solidly grounded neutral, including tires, must have the letter designation PE (Protective Earthing) and color designation with alternating longitudinal or transverse stripes of the same width (for tires from 15 to 100 mm) yellow and green. Zero working (neutral) conductors are indicated by the letter N and blue. Combined zero protective and zero working conductors must have the letter designation PEN and color designation: blue along the entire length and yellow-green stripes at the ends.

Grounding system symbols

The first letter in the designation of the grounding system determines the nature of the grounding of the power source:

T - direct connection of the neutral of the power supply to the ground;

I - all current-carrying parts are isolated from the ground.

The second letter defines the state of the exposed conductive parts relative to ground:

T - open conductive parts are grounded, regardless of the nature of the connection between the power source and the ground;

N - direct connection of the open conductive parts of the electrical installation with a dead-earthed neutral of the power source.

The letters following through the dash after N determine the nature of this connection - a functional way of arranging a zero protective and zero working conductor:

S - functions of zero protective PE and zero working N conductors are provided with separate conductors;

C - the functions of the zero protective and zero working conductors are provided by one common PEN conductor.

Protective function of grounding

The principle of protective action

The protective effect of grounding is based on two principles:

Reduction to a safe value of the potential difference between a grounded conductive object and other conductive objects that have a natural ground.

Removal of leakage current when a grounded conductive object contacts a phase conductor. In a properly designed system, the appearance of a leakage current leads to the immediate operation of protective devices (residual current devices - RCDs).

Thus, grounding is most effective only in combination with the use of residual current devices. In this case, for 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 a hundredth of a second - the RCD trip time).

Varieties of grounding systems

The classification of types of grounding systems is given as the main characteristic of the supply network. GOST R 50571.2-94 “Electrical installations of buildings. Part 3. Main characteristics "regulates the following grounding systems: TN-C, TN-S, TN-C-S, TT, IT. TN-C system

The TN-C system (fr. Terre-Neutre-Combine) was proposed by the German concern AEG in 1913. Working zero and PE-conductor (Eng. Protection Earth) in this system are combined into one wire. The biggest drawback was the possibility of the appearance of phase voltage on the housings of electrical installations during an emergency zero break. Despite this, this system is still found in the buildings of the countries of the former USSR.

TN-S system

Zero separation in TN-S and TN-C-S

To replace the conditionally dangerous TN-C system in the 1930s, the TN-S system (fr. Terre-Neutre-Separe) was developed, in which the working and protective zero were separated directly at the substation, and the ground electrode was a rather complex design of metal fittings. Thus, when the working zero was interrupted in the middle of the line, the electrical installations did not receive line voltage. Later, such a grounding system made it possible to develop differential automata and automatons that are triggered by current leakage, capable of sensing a small current. Their work to this day is based on Kirchhoff's laws, according to which the current flowing through the phase wire must be numerically equal to the current flowing through the working zero current.

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

TN-C-S system

In the TN-C-S system, the transformer substation has a direct connection of current-carrying parts to the ground. All exposed conductive parts of the electrical installation of the building are directly connected to the grounding point of the transformer substation. To ensure this connection, a combined zero protective and working conductor (PEN) is used in the section of the transformer substation - electrical installations of the building, in the main part of the electrical circuit - a separate zero protective conductor (PE).

TT system

In the TT system, the transformer substation has a direct connection of current-carrying parts to the ground. All open conductive parts of the electrical installation of the building have a direct connection to the ground through a grounding conductor, electrically independent from the neutral grounding conductor of the transformer substation.

IT system

In an IT system, the power supply neutral is isolated from earth, or earthed through high resistance appliances or devices, and exposed conductive parts are earthed. Leakage current to chassis or ground in such a system will be low and will not affect the operating conditions of the connected equipment. The IT system is used, as a rule, in electrical installations of buildings and structures for special purposes, which are subject to increased requirements for reliability and safety, for example, in hospitals for emergency power supply and lighting.

Zeroing is a deliberate electrical connection of open conductive parts of electrical installations that are not normally energized with a dead-earthed neutral point of a generator or transformer in three-phase current networks; with dead-earthed output of a single-phase current source; with a grounded source point in DC networks, performed for electrical safety purposes. Protective grounding is the main measure of protection for indirect contact in electrical installations up to 1 kV with a solidly grounded neutral.

Operating principle

Zeroing principle

The principle of operation of zeroing: if the voltage (phase) falls on the metal case of the device connected to zero, a short circuit occurs. A circuit breaker included in a damaged circuit is triggered by a short circuit and disconnects the line from electricity. In addition, a fuse can cut off electricity from the line. In any case, the PUE regulate the time for automatic shutdown of a damaged line. For the rated phase voltage of the network 380/220 V. it should not exceed 0.4 s.

Zeroing is carried out by conductors specially designed for this. With single-phase wiring, this is, for example, the third core of a wire or cable. In order for the protection device to turn off at the time stipulated by the rules, the resistance of the phase-zero loop must be small, which, in turn, imposes strict quality requirements on all connections and installation of the network, otherwise zeroing may be ineffective. In addition to quickly disconnecting the faulty line from the power supply, due to the fact that the neutral is grounded, grounding provides a low touch voltage on the body of the appliance. This eliminates the possibility of electric shock to a person.

There are zeroing systems TN-C, TN-C-S and TN-S:

Grounding system TN-C

Grounding system TN-C

Grounding device.PNG A simple grounding system in which the neutral conductor N and the neutral protective PE are combined along their entire length. A joint conductor is abbreviated as PEN. It has significant drawbacks, the main of which is the high requirements for potential equalization systems and the cross section of the PEN conductor. It is used to supply three-phase loads, such as asynchronous motors. The use of this system in single-phase group and distribution networks is prohibited:

It is not allowed to combine the functions of the zero protective and zero working conductors in single-phase and direct current circuits. A separate third conductor must be provided as a zero protective conductor in such circuits.

Grounding system TN-C-S

An improved grounding system designed to ensure the electrical safety of single-phase networks of electrical installations. It consists of a combined PEN-conductor, which is connected to the dead-earthed neutral of the transformer supplying the electrical installation. At the point where the three-phase line branches into single-phase consumers (for example, in the floor board of an apartment building or in the basement of such a house), the PEN conductor is divided into PE- and N-conductors, directly suitable for single-phase consumers.

Grounding system TN-S

The most advanced, expensive and safe grounding system, which has become widespread, in particular, in the UK. In this system, the zero protective and neutral conductors are separated along their entire length, which eliminates the possibility of its failure in the event of an accident on the line or an error in the wiring.

Conclusion

Ensuring life safety is a task of paramount priority for the individual, society and the state. From the moment of its appearance on Earth, a person lives and acts permanently in conditions of constantly changing potential dangers. Realized in space and time, dangers cause harm to human health, which manifests itself in nervous shocks, illnesses, disability and death, etc. Prevention of danger and protection from them is the most urgent humane, socio-economic and legal problem, in solving which the state cannot be not interested. To ensure electrical safety, it is necessary to strictly comply with a number of organizational and technical measures established by the rules for the installation of electrical installations, the rules for the technical operation of electrical installations of consumers and the safety rules for the operation of electrical installations of consumers. Dangerous and harmful effects on people of electric current, electric arc and electromagnetic fields manifest themselves in the form of electrical injuries and occupational diseases. Electrical safety in the premises is ensured by technical methods and means of protection, as well as organizational and technical measures.

The concept and distinguishing features of a dangerous and harmful production factor. Occupational safety management system at the enterprise. Stages of the technological process of the work of computer technology users, major injuries and occupational diseases.

Types of briefings on labor protection. Cases in which special training of workers is carried out. Basic requirements for heating and ventilation of industrial premises. Protected against dangerous touch and step voltages.

The system of organizational and technical measures and means that ensure the protection of people from the harmful effects of email. current, el. arcs, EM fields and static electricity. Violation of e-security requirements leads to e-mail. injuries.

Electrical injury at work and at home. The effect of electric current on the human body. Electrical injury. Conditions for electric shock. Technical methods and means of electrical safety. Optimization of protection in distribution networks.

Theoretical substantiation of protective grounding and grounding. The need for protective grounding and zeroing. Calculation of protective grounding of substations, grounding of the engine. Devices used in these processes, their application.

My bitter experience as an electrician allows me to say: If your "grounding" is done properly - that is, there is a place for connecting "grounding" conductors in the shield, and all plugs and sockets have "grounding" contacts - I envy you, and you have nothing worry.

Ground connection rules

What is the problem, why can not you connect the ground wire to the pipes of heating or water supply?

In reality, in urban conditions, stray currents and other interfering factors are so great that anything can turn out to be on the radiator. However, the main problem is that the tripping current of the circuit breakers is quite large. Accordingly, one of the options for a possible accident is a short-circuit breakdown of the phase to the case with a leakage current just somewhere on the border of the machine's operation, that is, at best 16 amperes. In total, we divide 220v by 16A - we get 15 ohms. Just some thirty meters of pipes, and you get 15 ohms. And the current flowed somewhere, towards the unsawn forest. But it doesn't matter anymore. The important thing is that in the neighboring apartment (up to which it is 3 meters, not 30, the voltage on the tap is almost the same 220.), But on, say, a sewer pipe - a real zero, or something like that.

And now the question is - what will happen to the neighbor if he, sitting in the bathroom (connecting to the sewer by opening the plug) touches the tap? Guessed?

The prize is prison. Under the article on violation of electrical safety rules resulting in casualties.

We must not forget that it is impossible to imitate the "grounding" circuit by connecting the "zero worker" and "zero protective" conductors in the euro socket, as some "craftsmen" sometimes practice. Such a substitution is extremely dangerous. Cases of "working zero" burning out in the shield are not rare. After that, on the body of your refrigerator, computer, etc. very firmly placed 220V.

The consequences will be approximately the same as with a neighbor, with the difference that no one will be held responsible for this, except for the one who made such a connection. And as practice shows, this is done by the owners themselves, because. consider themselves sufficient specialists not to call electricians.

"Grounding" and "grounding"

One of the options for "grounding" is. But not as in the case described above. The fact is that on the switchboard housing, on your floor, there is zero potential, or more precisely, the neutral wire passing through this very shield simply has contact with the shield housing by means of a bolted connection. Zero conductors from apartments located on this floor are also connected to the shield body. Let's look at this point in more detail. What we see is that each of these ends is wound under its own bolt (in practice, the truth is often found in pairs of these ends). This is exactly where our newly made conductor should be connected, which will later be called "grounding".

This situation also has its own nuances. What prevents "zero" from burning out at the entrance to the house. As a matter of fact, nothing. One can only hope that there are fewer houses in the city than apartments, which means that the percentage of such a problem is much less. But again, this is a Russian "maybe", which does not solve the problem.

The only correct solution in this situation. Take a metal corner 40x40 or 50x50, 3 meters long, hammer it into the ground so that they don’t stumble over it, namely, we dig a hole two bayonets of a shovel deep and hammer our corner there as much as possible, and from it conduct a PV-3 wire (flexible , stranded), with a cross section of at least 6 mm. sq. to, your switchboard.

Ideally, it should consist of 3-4 corners, which are welded with a metal strip of the same width. The distance between the corners should be 2 m.

Just do not drill a hole in the ground with a meter drill and lower the pin there. It is not right. And the efficiency of such grounding is close to zero.

But, like any method, it has its downsides. Of course, you are lucky if you live in a private house, or at least on the first floor. And what about those who live on the 7-8 floor? Stock up on 30-meter wire?

So how do you find a way out of this situation? I am afraid that even the most experienced electricians will not give you an answer to this question.

What is required for house wiring

For wiring around the house, you will need a copper ground wire of the appropriate length, and with a cross section of at least 1.5 mm. sq. and, of course, a socket with a "grounding" contact. Box, plinth, bracket - a matter of aesthetics. The ideal option is when you are doing repairs. In this case, I recommend choosing a cable with three cores in double insulation, preferably VVG. One end of the wire is wound under the free bolt of the switchboard busbar connected to the shield body, and the other end - to the "grounding" contact of the socket. If there is an RCD in the shield, the grounding conductor should not have contact with the N conductor anywhere on the line (otherwise the RCD will work).

We must also not forget that the "earth" does not have the right to be torn apart by means of any switches.

The function of grounding and zeroing is one - to protect a person from electric shock. The current-carrying core was exposed, there was a current leakage to the body of the electrical appliance, the socket housing was damaged - such a problem can lead to unpleasant consequences. The considered protective devices, which are designed to neutralize the dangerous factor, to ensure the safety of a person and his property, will help to avoid this. In the article we will talk about grounding and zeroing, what is the difference and similarity, consider their purpose and installation schemes.

What is the difference between grounding and grounding

Grounding scheme indicating splitting into N and PE on the terminal block of the shield

It is most convenient to consider the difference between grounding and grounding using the example of connecting household electrical appliances. Modern houses are equipped with three-wire electrical wiring, where the PE conductor is grounding and does not depend on the working zero conductor N. Thus, the electrical appliance case connected to the PE conductor receives a reliable connection to the ground - grounding.

Old buildings have a two-wire power supply, consisting of a conductor L - phase, N - working zero. N is derived from the ground bus in the general house or access electrical panel. Initially, it is called a PEN conductor and can be split into N and PE.

Splitting must be done before entering the apartment switchboard, or directly in the switchboard. Further, the PE wire is connected to the body of the electrical appliance in the same way as in the first embodiment, but such a circuit will be called zeroing, since the connection with the ground is not direct, but is carried out through a neutral conductor. Read also the article: → "".

Which system is more reliable

For comparison, here are a few points:

• As practice shows, there are frequent cases of a break or burnout of the neutral wire in the electrical panel, which makes the zeroing protection system inoperative. In this case, there is a real threat of electric shock to a person. To avoid such a problem, the switching points must be periodically inspected, which creates certain inconveniences.

The burnt neutral wire in the switchboard is close to a complete break

• The grounding system is free from these disadvantages, since the PE conductor does not participate in the overall operation of the electrical wiring and is activated only when a leak occurs in order to drain the current to the ground.
• The zeroing device requires certain knowledge and skills in working with electrical circuits, which, if they are not available, also causes some inconvenience associated with the need to call an electrician.

Taking into account the above, we can conclude that the grounding system is more reliable and safe, so it is better to use it. However, in the absence of such an opportunity, you can resort to an alternative option. It is forbidden to ground directly in the socket by installing a jumper between the zero connector and the grounding bracket. This poses a threat to humans (electric shock) and household appliances.

The device of protective current taps when working with three-phase electrical equipment

The switching of three-phase consumers of electricity differs from the connection of conventional household electrical equipment, so the installation of protective systems is carried out in a different way. In this case, one should not confuse the neutral or ground wire involved in the control system, that is, involved in the starting and stopping circuit of the unit, with protective conductordesigned to discharge a dangerous discharge to the ground.

Design, wiring, connection of electrical equipment

The work is carried out in several stages:

1. Along the perimeter of the room, a separate line (route) is arranged, made of a narrow metal strip 40x3 mm or copper wire with a cross section of 16 mm2.
2. A tire (preferably copper) with contact devices (studs or holes for bolted connections) is mounted on it in a hidden place. It is allowed to use a metal tire, but in this case, welding the studs is a prerequisite.
3. This line is connected to the ground or ground loop, which is brought out by a separate wire from the switchboard and has a reliable connection to the ground either directly or through a working zero.
4. The housings of all consumers (three-phase electric motors) are connected to the described bus through a copper wire.

In the event of a short circuit from voltage leakage due to a violation of the insulation or “breakthrough” of one of the phases on the body of grounded electrical equipment, the current will immediately go to the ground along the path of least resistance, that is, through a core connected to working zero or ground. This will save a person from electric shock when touching the body of the device.

The main condition for the safe operation of electrical installations is the choice of the correct protection scheme against accidental contact with high potential on metal parts that are not used for energy transmission (housings, beds, etc.). To solve this problem, the requirements of the current standards (PUE, in particular) provide for the use of special protective devices called grounding devices - GD. They are arranged in close proximity to the protected structure and have the form shown in the figure below.

The process of arranging structures that protect structures and people from electric shock or lightning is commonly called grounding in electrical engineering. In order to have a complete and clear idea of ​​what grounding is, it will be necessary to study its distinctive features and principles of organization in more detail.

The essence of grounding

Grounding refers to the intentional connection of metal parts of electrical installations and other equipment that are not currently energized with elements of special devices called grounding conductors. The design of the latter usually consists of several steel pins driven into the ground or pieces of reinforcement welded together by strips of the same metal.

Complete with a set of flexible copper wires and thick strips (tires), grounding conductors form the so-called "grounding loop", to which the cases of all electrical appliances available at the facility and in need of protection are connected. Since the circuit itself is partially or completely immersed in the ground and has almost perfect contact with it, its potential under normal conditions is close to zero, which allows us to draw the following conclusions:

• If high voltage hits the metal parts of a protected object or device, its value will immediately drop to a level that is safe for humans (photo below);

• If a person or animal accidentally touches the body of an emergency, but protected in this way, equipment, they will practically not suffer from high voltage;
• In a situation where a sensitive device is installed in the supply line that reacts to third-party leakage currents (RCD, for example), when a dangerous voltage appears, it will work and instantly disconnect this section from the power supply.

This is the essence of the grounding effect, which should not be confused with another protection technique often used in electrical engineering, called zeroing.

The concept of nulling

Each user inexperienced in electrical terms may have a question: how does grounding differ from zeroing, and also when is the latter used?

To understand the difference between grounding and zeroing, it will be necessary to consider the principle of protecting equipment of distribution substations, the essence of which is as follows:

• The equipment of any power plants, including step-down transformers installed on them, has a zero point or neutral;
• In accordance with the requirements of the PUE, this point is necessarily connected to the local charger, equipped directly on the territory of the substation;
• Grounding is carried out in the form of a direct connection with the ground, as a result of which such a point is called dead-grounded;
• The action of this grounding applies to all consumers connected to this electrical substation through an extensive power supply system.

Thus, the so-called “zero protective” conductor, already grounded tightly on the side of the substation, is supplied to each consumer along with the phase wires (see photo).

Note! In modern power supply systems (TN-C-S, for example), it is laid separately from the operating busbar N with a PE wire.

When zeroing the receiving equipment, its metal parts are deliberately connected not to the charger (as is done when grounding), but to the combined neutral wire that is part of the power supply system. In a TN-C-S system, they are connected to a separate PE conductor.

Zeroing provides a reduction in the threat of electric shock in case of accidental contact with open metal parts of the equipment, which, due to an accident, become energized. When questions like “what is the difference between zeroing and grounding” appear, you should always remember that the first guarantees automatic disconnection of the damaged line from the mains, and the second does not.

Differences between grounding and grounding

Often, users wonder if it is possible to do grounding instead of grounding, and how this will affect consumer safety. Answering all such questions, one should proceed from the definition given to this type of protection in the previous section. It follows from this that zeroing is functionally more efficient, since in a short period of time before the operation of station automation, it performs the same function as a conventional memory.

However, this does not mean that this type of protection should be applied always and everywhere. The fact is that zeroing has a number of shortcomings, which are a consequence of the peculiarities of its organization. They appear as follows:

• The neutral wire of power supply systems is long and is constantly used in active mode (as a conductor through which the operating current flows), as a result of which it can collapse over time;

Additional Information. This phenomenon in the technical literature, as well as among specialists, is most often referred to as “zero burnout” (see photo below).

• Unlike grounding, during the arrangement of which there is no dependence on the phase of the protected line, when grounding, certain conditions for connecting the protective conductor must be observed;
• It is limited in its capabilities, since it can only be used in circuits with a tightly grounded neutral in TN-C-S, TN-C, TN-S networks (in the presence of N, PE, PEN conductors).

In lines where the connection is organized according to an isolated neutral scheme (in IT and TT systems), which are more suitable for industrial facilities by their purpose, it will not be able to work.

Also, these two types of deliberate protection differ in their scope, namely:

• Zeroing is usually used in multi-storey residential buildings, where it is almost impossible to organize a full-fledged grounding;
• Re-grounding is more often used in industrial enterprises, where, according to safety standards, increased requirements are imposed on personnel safety;
• The same type of protection is most often used in everyday life (in country houses, in particular), where there are plenty of opportunities for arranging a protective circuit (see photo below).

It should be added that protective grounding and zeroing differ in another important factor. The fact is that in the first case, protection applies only to the section of the electrical circuit, in which, in emergency mode (during the breakdown of insulation), the operating voltage has decreased due to the flow of current into the ground. At the same time, the rest of the electricity supply system continues to function.

Unlike the action of the grounding effect, when grounding, this section of the power line is turned off completely.

So trying to answer the question, what is their difference, will not be entirely correct. It is much more correct to say that grounding and grounding of electrical installations should be used together. Such a combined use of them will provide more effective protection against electric shock.

Summing up their comparison, we note that the principle of zeroing is to turn an emergency into a single-phase short circuit, leading to the operation of the station protective automation. Grounding, on the one hand, is a decrease in the potential of a dangerous point (a decrease in the resistance of the ground electrode), and on the other, their equalization.

In this case, it consists in raising the potential of the support with a person standing on it to the voltage level on the grounded case.

Additional elements

Both in the case of grounding and zeroing, for the implementation of protective functions, additional conductors (copper wires) must be used to ensure a reliable connection with the charger or with a neutral contact, respectively.

In the first case, this conductor is pulled from the protected point to the ground electrode contact and is made in the form of a copper braid. In a zeroing situation, the same copper conductor is laid through hidden places in rooms and other buildings to a switch cabinet, where its end is fixed on the main ground bus (GZSH). A zero working conductor, which is part of the power cable supplying electricity, is also brought here.

Important! According to the requirements of the organization of grounding (see the PUE), the use of one bolt or terminal contact for fastening these two conductors is unacceptable, which is explained by the different modes of their operation.

At the end of the comparison of the two methods of protecting objects from electric shock, the following should be noted. Both of these methods (both zeroing and grounding), in fact, perform the same function, which consists in reducing the dangerous potential to an acceptable level. You zap some point of the equipment or protect it with the help of a memory, the effect will be about the same.

Video

The difference between grounding and grounding is significant. Let's try to understand this issue. Zeroing according to the PUE is a deliberate protection that is used exclusively for industrial purposes and should not be practiced at the household level.

But still, very often, zeroing is done in apartments. According to all forecasts, such a system is far from perfect and not at all safe. Why, then, resort to such an extreme measure? Partly due to a lack of knowledge in this area, or because of a hopeless situation.

During the repair of an apartment, many make a complete or partial electrical installation, not only for the convenience of locating sockets and switches, but also to replace worn-out electrical wiring. Also, a modern person wants to make his home safer, therefore, the wishes of the customer come down to ensuring that the house has grounding.

What is used in new buildings: grounding or grounding?

New buildings, by all rules, are provided with a three-wire cable (phase, zero, earth) in a single-phase system and a five-wire cable (three phases, zero, earth) in a three-phase system, i.e. according to the TN-C-S or TN-S earthing system. In such systems, zeroing does not smell.

Is it possible to make grounding in the old fund?

The old foundation is very rarely reconstructed. In order to transfer from the TN-C system, i.e. a two-wire system (phase and zero), on such efficient systems as TN-C-S and TN-S, in which a protective conductor PE (ground) is provided, is practically impossible on its own. Modernization is mainly carried out by a specialized electrical company.

There is no protective conductor (earth) in the TN-C system. No one will pull a separate ground wire from their apartment in order to make grounding, for example, in the basement. Although, some decide to provide themselves with grounding if the apartment is located on the first floor. But for the majority of the population, such a maneuver is not possible.

Before connecting the protective conductor PE (ground) from the apartment, you need to determine what possibilities are available. Determine the presence of grounding in the switchboard, to which a third conductor can be connected. The switchboard room must either have a PE ground bus, or all floor switchboard rooms must be interconnected by a metal bus, and as a result connected to the common ground loop of the house, i.e. It's about re-grounding. This makes it possible to connect a grounding conductor from the apartment to the shield. If these two options are absent, then there is no grounding in the house, and in this case, a prohibited grounding is done. As mentioned earlier, this method in the residential sector is not at all safe.

How is nulling done?

Zeroing does not play the role of grounding, such a circuit is designed for the effect of a short circuit. In production, the loads are more or less evenly distributed, and zero performs mainly protective functions. Here, the neutral conductor is hooked to the motor housing. If the voltage of one of the phases hits the motor housing, a short circuit will occur. In turn, the circuit breaker or differential protection circuit breaker will trip. One more indisputable fact should be taken into account - all electrical installations in production are interconnected by a metal ground bus and brought to a common ground loop of the entire building.

Is it possible to make zeroing in the apartment?

It is possible, but not necessary. What does it threaten? Suppose your equipment (washing machine, boiler, etc.) is zeroed. If the neutral wire burns for some reason or the electrician accidentally mixed up the wire connection (connected the phase instead of zero), then your equipment will simply burn out due to high voltage.

If you have planned electrical work in your home, and then find out that there is no grounding in the house in any form, it is still better to lay a three-core cable. We connect two cores (phase and zero) as planned, but we leave the third conductor of protective grounding unused until waiting for the reconstruction of the risers, where grounding will be provided.

If you still decide to make a zeroing in the apartment, you need to remember that you are taking on a huge responsibility. In any case, in the presence of grounding or grounding, the installation of protective equipment, such as an RCD (Residual Current Device) and a voltage limiter, cannot be neglected.

Another measure of protection for indirect contact in electrical installations up to 1 kV with a solidly grounded neutral against electric shock, along with, is nulling.

Zeroing- this is a deliberate electrical connection of open conductive parts of electrical installations that are not normally energized with a dead-earthed neutral point of a generator or transformer in three-phase current networks; with dead-earthed output of a single-phase current source; with a grounded source point in DC networks, performed for electrical safety purposes.

To connect the open conductive parts of the consumer of electricity with a solidly grounded neutral point of the source, a zero protective conductor is used.

Zero protective conductor(PE - conductor in the TN - S system) is a conductor connecting zeroed parts (open conductive parts) with a solidly grounded neutral point of a three-phase current power source or with a grounded output of a single-phase current power source, or with a grounded midpoint of a power source in DC networks.

Zero protective conductor should be distinguished from zero working and PEN - conductors.

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Zero working conductor(N - conductor in the TN - S system) - a conductor in electrical installations with voltage up to 1 kV, designed to power electrical consumers connected to a solidly grounded neutral point of a generator or transformer in three-phase current networks, with a solidly grounded output of a single-phase current source, with a solidly grounded source point in DC networks current.

Combined(PEN - conductor in the TN–C system) zero protective and zero working conductor- a conductor in electrical installations with voltage up to 1 kV, combining the functions of a zero protective and zero working conductor.

The principle of operation of zeroing: if the voltage (phase) falls on the metal case of the device connected to zero, it occurs. A circuit breaker included in a damaged circuit is triggered by a short circuit and disconnects the line from electricity. In addition, a fuse can cut off electricity from the line. In any case, the PUE regulate the time for automatic shutdown of a damaged line. For the rated phase voltage of the network 380/220 V. it should not exceed 0.4 s. Zeroing is carried out by conductors specially designed for this. With single-phase wiring, this is, for example, the third core of a wire or cable.

In order for the protection device to turn off at the time stipulated by the rules, the resistance of the phase-zero loop must be small, which, in turn, imposes strict quality requirements on all connections and installation of the network, otherwise zeroing may be ineffective.

In addition to quickly disconnecting the faulty line from the power supply, due to the fact that the neutral is grounded, grounding provides a low touch voltage on the body of the appliance. This eliminates the possibility of electric shock to a person.

Now let's move on to practice. We will descend, so to speak, from heaven to earth and move to your apartment or private house.

Grounding will be simply necessary if your apartment or house does not have grounding (See Fig.). To neutralize a socket or sockets, you will need to divide the neutral conductor (PEN) into a zero working conductor (PE) and a zero protective conductor (N). Then we lay a third wire to the outlet and connect it to the ground contact on it. This method is used in the TN-C-S earthing system.