Tips from experienced electricians for connecting an additional grounding wire. Ground wire. How it is forbidden to connect grounding to sockets

Modern household appliances and equipment require grounding. Only in this case will manufacturers maintain their guarantees. Residents of apartments have to wait for the networks to be overhauled, while home owners can do everything themselves. How to make grounding in a private house, what is the procedure and connection diagrams - read about all this here.

In general, ground loops can be in the form of a triangle, rectangle, oval, line or arc. The best option for a private house - a triangle, but others are quite suitable.

Grounding in a private house - types of grounding loops

Triangle

Grounding in a private house or country house is most often done with a contour in the form of an isosceles triangle. Why is that? Because with such a structure, in a minimum area we obtain a maximum area for current dissipation. The costs of installing a grounding loop are minimal, and the parameters correspond to the standards.

The minimum distance between the pins in the ground loop triangle is their length, the maximum is twice the length. For example, if you drive the pins to a depth of 2.5 meters, then the distance between them should be 2.5-5.0 m. In this case, when measuring the resistance of the ground loop, you will get normal values.

During work, it is not always possible to make the triangle strictly isosceles - stones come across in the right place or other difficult-to-pass areas of soil. In this case, you can move the pins.

Linear ground loop

In some cases, it is easier to make a ground loop in the form of a semicircle or a chain of pins lined up (if there is no free area of ​​suitable dimensions). In this case, the distance between the pins is also equal to or greater than the length of the electrodes themselves.

With a linear circuit, a larger number of vertical electrodes is necessary so that the dissipation area is sufficient

The disadvantage of this method is that to obtain the required parameters, a larger number of vertical electrodes is required. Since hammering them in is still a pleasure, if there is a meta, they try to make a triangular outline.

Ground loop materials

For the grounding of a private house to be effective, its resistance should not be more than 4 ohms. To do this, it is necessary to ensure good contact of the grounding conductors with the ground. The problem is that grounding resistance can only be measured with a special device. This procedure is carried out when putting the system into operation. If the parameters are worse, the act is not signed. Therefore, when doing the grounding of a private house or cottage with your own hands, try to strictly adhere to the technology.

Pin parameters and materials

Grounding pins are usually made of ferrous metal. Most often, a rod with a cross-section of 16 mm or larger or a corner with parameters of 50 * 50 * 5 mm (5 cm shelf, metal thickness - 5 mm) is used. Please note that reinforcement cannot be used - its surface is hardened, which changes the distribution of currents, and in addition, in the ground it quickly rusts and collapses. What is needed is a rod, not reinforcement.

Another option for arid regions is thick-walled metal pipes. Their lower part is flattened into a cone, and holes are drilled in the lower third. To install them, holes of the required length are drilled, since they cannot be driven in. When soils dry out and grounding parameters deteriorate, a saline solution is poured into the pipes to restore the dissipative capacity of the soil.

The length of the grounding rods is 2.5-3 meters. This is sufficient for most regions. More specifically there are two requirements:

Specific grounding parameters can be calculated, but the results of a geological study are required. If you have any, you can order a calculation from a specialized organization.

What to make metal connections from and how to connect them with pins

All pins of the circuit are connected to each other by metal bonding. It can be made from:

• copper wire with a cross section of less than 10 mm 2;
• aluminum wire with a cross-section of at least 16 mm 2
• steel conductor with a cross section of at least 100 mm 2 (usually a strip of 25 * 5 mm).

Most often, the pins are connected to each other using a steel strip. It is welded to the corners or heads of the rod. It is very important that the quality of the weld is high - this determines whether your grounding will pass the test or not (whether it will meet the requirements - resistance less than 4 ohms).

When using aluminum or copper wire, a large cross-section bolt is welded to the pins, and the wires are already attached to it. The wire can be screwed onto a bolt and pressed with a washer and nut, or the wire can be terminated with a connector of a suitable size. The main task is the same - to ensure good contact. Therefore, do not forget to strip the bolt and wire to bare metal (can be treated with sandpaper) and tighten well - for good contact.

How to make grounding yourself

After all materials have been purchased, you can begin the actual manufacture of the ground loop. First, cut the metal into pieces. Their length should be about 20-30 cm longer than the calculated one - when driven in, the tops of the pins bend, so you have to cut them off.

Sharpen the clogged edges of the vertical electrodes - things will go faster

There is a way to reduce the resistance when driving electrodes - sharpen one end of the angle or pin at an angle of 30°. This angle is optimal when driving into the ground. The second point is to weld a metal pad to the upper edge of the electrode, from above. Firstly, it is easier to hit, and secondly, the metal is less deformed.

Work order

Regardless of the shape of the contour, it all starts with earthworks. It is necessary to dig a ditch. It is better to make it with beveled edges - this way it crumbles less. The order of work is as follows:

Actually, that's all. We did the grounding in a private house with our own hands. All that remains is to connect it. To do this, you need to understand the grounding organization diagrams.

Inserting a ground loop into the house

The ground loop must somehow be connected to the ground bus. This can be done using a 24*4 mm steel strip, copper wire cross section 10 mm2, aluminum wire cross section 16 mm2.

If wires are used, it is better to look for them in insulation. Then a bolt is welded to the circuit, and a sleeve with a contact pad (round) is put on the end of the conductor. A nut is screwed onto the bolt, a washer is screwed onto it, then a wire, another washer is placed on top, and the whole thing is tightened with a nut (picture on the right).

How to bring “earth” into the house

When using a steel strip, there are two options - bring a tire or wire into the house. I really don’t want to pull a steel tire measuring 24*4 mm - it looks unaesthetic. If there is, you can use the same bolted connection to carry out copper bus. It needs a much smaller size, it looks better (photo on the left).

You can also make a transition from a metal bus to a copper wire (cross section 10 mm2). In this case, two bolts are welded to the tire at a distance of several centimeters from each other (5-10 cm). The copper wire is twisted around both bolts, pressing them with a washer and nut to the metal (tighten as best as possible). This method is the most economical and convenient. It doesn't require as much money as using only copper/aluminum wire, and it's easier to run it through a wall than a busbar (even a copper one).

Grounding schemes: which one is better to make?

Currently, in the private sector, only two grounding connection schemes are used - TN-C-S and TT. For the most part, a two-core (220 V) or four-core (380 V) cable (TN-C system) is suitable for the house. With such wiring, in addition to the phase (phase) wire, there is a protective conductor PEN, in which neutral and ground are combined. At the moment, this method does not provide adequate protection against electric shock, so it is recommended to replace the old two-wire wiring with a three-wire (220 V) or five-wire (380 V).

In order to obtain normal three- or five-wire wiring, it is necessary to separate this conductor into ground PE and neutral N (in this case, an individual grounding loop is required). This is done in the entrance cabinet on the facade of the house or in the accounting and distribution cabinet inside the house, but always before the meter. Depending on the separation method, either the TN-C-S or TT system is obtained.

Installation of a TN-C-S grounding system in a private house

When using this circuit, it is very important to make a good individual ground loop. Please note that with the TN-C-S system, protection against electric shock requires the installation of RCDs and breakers. Without them there is no talk of any protection.

Also, to ensure protection, it is necessary to connect all systems that are made of conductive materials - heating, water supply, foundation reinforcement frame, sewerage, gas pipeline (if they are made of metal pipes) to the earth bus with separate wires (inextricable). Therefore, the grounding bus must be taken “with a reserve”.

To separate the PEN conductor and create grounding in a private house TN-C-S, three buses are needed: on a metal base - this will be a PE (ground) bus, and on a dielectric base - this will be an N bus (neutral), and a small splitter bus for four " seating places.

The metal “earth” bus must be attached to the metal body of the cabinet so that there is a good electrical contact. To do this, at the fastening points, under the bolts, the paint is removed from the body to bare metal. The zero bus - on a dielectric base - is best mounted on a DIN rail. This installation method fulfills the basic requirement - after separation, the PE and N buses should not intersect anywhere (should not have contact).

Grounding in a private house - transition from the TN-C system to TN-C-S

• The PEN conductor coming from the line is connected to the bus splitter.
• We connect the wire from the ground loop to the same bus.
• From one socket with a copper wire with a cross-section of 10 mm 2 we place a jumper on the ground bus;
• From the last free socket we place a jumper on the zero bus or neutral bus (also 10 mm2 copper wire).

Now that's it - grounding in a private house is done according to the TN-C-S scheme. Next, to connect consumers, we take the phase from the input cable, zero from the N bus, and ground from the PE bus. We make sure that ground and zero do not intersect anywhere.

Grounding according to the TT system

Converting a TN-C to TT circuit is generally simple. There are two wires coming from the pole. The phase conductor is further used as a phase, and the protective PEN conductor is attached to the “zero” bus and is then considered zero. The conductor from the made circuit is directly supplied to the grounding bus.

Do-it-yourself grounding in a private house - TT diagram

The disadvantage of this system is that it provides protection only for equipment that requires the use of an “earth” wire. If there are also household appliances made using a two-wire circuit, they may be energized. Even if the housings are grounded with separate conductors, in case of problems, the voltage may remain at “zero” (the phase will be broken by the machine). Therefore, of these two schemes, preference is given to TN-C-S as it is more reliable.

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

The main elements of the grounding connection diagram for a country house and the rules for their implementation

Ground connection diagram in country house looks like this: electrical appliance - socket - electrical panel - grounding conductor - ground loop - ground.

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

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

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

Dependence of the grounding connection diagram on the grounding loop

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

For a grounding device, first of all, natural grounding conductors should be used - third-party conductive parts that have direct contact with the ground (water pipelines, well pipes, metal and reinforced concrete structures country house And so on). (see clause 1.7.54, 1.7.109 PUE 7th edition).

If there are none, we create an artificial grounding device using vertical or horizontal electrodes that we dig into the ground. The choice of grounding configuration mainly depends on the required resistance and the characteristics of the local area.

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

Dependence of the connection diagram on the type of grounding system

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

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

Electrical safety is fully ensured when a decrease in the resistance of the ground electrode does not entail an increase in the ground fault current. Let's consider how the grounding connection diagram depends on the electrical network system implemented at the facility.

Grounding system TN-S

Figure 1. TN-S system

At facilities equipped with an electrical network using the TN-S system, the neutral working and protective conductors are separated along the entire length, and in the event of a phase insulation breakdown, the emergency current is discharged through the protective PE conductor. RCD devices and automatic circuit breakers, which react to the occurrence of current leakage through the protective zero, disconnect the network with the load.

The advantage of the TN-S grounding subsystem is reliable protection electrical equipment and people from injury from emergency current when using electrical networks. Due to this, this system is considered to be the most modern and safe.

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

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

Figure 2. TN-S system

Grounding using the TN-C system is most common for old residential buildings. The advantage is that it is cost effective and easy to implement. A significant drawback is the absence of a separate PE conductor, which eliminates the presence of grounding in the sockets of a country house and the possibility of equalizing potentials in the bathroom.

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

Grounding connection using the TN-C-S system

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

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

Figure 3. Main distribution board diagram

As already noted, to obtain three-wire wiring, it is necessary to correctly separate the PEN conductor in the distribution panel of the house. We start by installing a busbar into the electrical panel, ensuring a strong metal connection with it, and connecting the combined PEN conductor coming from the side of the power line to this busbar. We connect the PEN bus with a jumper to the next installed PE bus. Now the PEN bus acts as the bus of the zero working conductor N.

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

Figure 5. TN-C-S ground connection diagram

Having completed the indicated connections, we connect the distribution panel to the grounding device: from the grounding device we connect a wired PE bus. Thus, as a result of a simple modernization, we equipped the house with three separate wires (phase, neutral protective and zero working).

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

Grounding connection according to the TT system

Figure 6. TT system

Another option for the circuit is to connect the grounding of a country house using a TT system with a solidly grounded neutral of the current source. The exposed conductive elements of the electrical equipment of such a system are connected to a grounding device that has no electrical connection with the neutral grounding electrode of the power source.

In this case, the following condition must be met: the value of the product of the response current of the protection device (Ia) and the total resistance of the grounding conductor and grounding conductor (Ra) should not exceed 50 V (see clause 1.7.59 of the PUE). Ra Ia ≤ 50 V.

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

Grounding according to the TT system does not require separation of the combined PEN conductor. We connect each of the individual wires approaching the house to a bus isolated from the electrical panel. And the PEN conductor itself, in this case, is considered to be the neutral wire (zero).

Figure 7. TT ground connection diagram

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

As follows from the diagram, the TN-S and TT systems are very similar to each other. The difference lies in the complete absence of an electrical connection between the grounding device and the PEN conductor in the CT, which, in the event of the latter burning out from the power source, guarantees the absence of excess voltage on the housing electrical appliances. This is the obvious advantage of the TT system, providing more high level safety and reliability in operation. The only disadvantage of its use is its high cost, since to protect users from indirect contact, it is necessary to install additional protective power switch devices (RCDs and voltage relays), which, in turn, requires testing and certification by an energy supervision specialist.

Conclusion

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

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

• method of powering the electrical network ( by air lines or cable from a transformer substation)
• the type of soil in the local area where the ground loop is being made.
• the presence of a lightning protection system, additional power supplies or specific equipment.

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

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

Do you need advice on organizing grounding and lightning protection for your facility? Contact

An integral element of most modern electrical installations is the ground wire. This device is used for the electrical connection of any elements with zero ground potential, which in electrical calculations is assumed to be zero.

Purpose

The grounding wire is designed to protect a person from electric shock in emergency situations. For example, when the insulation breaks down, electrical contact occurs between the current-carrying elements and the device body. If a person touches such a device electricity will leak through it to the ground, which can lead to electrical injury and even death. A current of 100 mA is considered dangerous for humans, which is why the probability of current flow must be minimized.

Rice. 1: Diagram of current flow during an electric shock

To eliminate the threat to human life, a grounding wire is installed in electrical installations. The grounding wire ensures electrical connection all conductive elements not normally at any operating potential, with . And if a potential arises on the case or other elements, the charge will flow through the ground wire, and if there is protection, it will initiate its operation.

Despite the fact that the vast majority of grounding electrodes are installed for the purpose of human protection, there is also a category that is intended for performing work processes. Therefore, all grounding wires, in accordance with their purpose, can be divided into working and protective conductors. It should be noted that the danger of electric shock exists not only in the absence of a grounding conductor, but also in the event of its non-compliance with the requirements.

Requirements

Requirements for the grounding wire are made in accordance with the local conditions in which electrical installations are operated. They may also differ in accordance with the assigned tasks or operating mode. All requirements can be divided according to the following parameters of grounding wires:

• Single or stranded– are applied depending on the specific equipment. Thus, stranded wires should be installed in areas where a certain level of flexibility is required and the ground must be easy to move (cell doors, test equipment, etc.). Single-core wires provide rigid fixation and are attached to the housings of stationary equipment.
• Presence or absence of insulation– an insulating layer is required when laying openly or along equipment casings.
• Separately routed or contained in a single cable– with an integrated design, in single-phase systems it should be carried out with a three-core cable, and in three-phase systems with a five-core cable. If the system is already installed, it must be carried out with a separate grounding conductor.
• Conductive element material (copper, aluminum, steel)– determines the resistivity of the conductor itself and its chemical resistance to various environmental influences. Copper conductors are the most resistant to corrosion and have the lowest resistivity, followed by aluminum and steel.

The most important requirement for the grounding loop and the conductor connected to it is the total ohmic resistance. Which is determined by the cross-section of the ground wire, and the transition resistance between the circuit blades and the ground, and the places of bolted (terminal) or welded connections in the common circuit. The total value of the circuit resistance is determined by clauses 1.7.101 - 1.7.103 of the PUE, depending on the linear or phase voltage of the electrical installation and its type, these parameters are given in the table below:

Table: grounding resistance value

In addition to copper wires in accordance with clause 1.7.121 of the PUE, for grounding it is allowed to use a metal armored shell used to protect against mechanical damage when laying cables, ducts and trays, if their placement excludes the possibility of their damage, rails and beams in the construction of buildings and structures .

But, according to the requirements of clause 1.7.123 of the PUE, it is prohibited to use metal parts of gas pipelines or water supply pipes, loaded reinforcement of reinforced concrete structures as grounding conductors.

Marking and color

Marking of grounding wires provides them with quick recognition and ease of installation work. So, according to the requirements of clause 1.1.29 of the PUE, grounding conductors have both letter and color markings. The letter designation of the land is made by a combination of the Latin letters PE. The letters are intended for marking on the corresponding circuit components, cable ends and ground terminals. The color designation is made in the form of a yellow-green color located in stripes along the entire length or another combination of these two colors, which corresponds to the cable brand and manufacturer standards.

Depending on the method of powering electrical consumers, a system may be used in which the protective and neutral conductors are combined. Since the marking of the neutral wire in accordance with the same clause 1.1.29 of the PUE is carried out in blue or light blue and is designated by the letter N, in such power supply systems where the neutral wire and grounding are combined and carried out as a single line, they are designated as PEN. In terms of color, the combined PEN conductor has a combination of blue and yellow-green insulation.

It should be noted that the above color marking order does not apply to tires, since in them yellow indicates phase A, green – phase B, red – C. A zero tire may have no color at all and be used in its natural form. The PE busbar is painted black, and the application areas are organized in the form of bare metal areas.

Ground wire size

Since the response efficiency protective device and ensuring human safety directly depends on such a parameter as ohmic resistance, the grounding wire must have an appropriate cross-section that meets the operating parameters of the laid line or electrical installation. Due to the fact that, unlike the phase and neutral busbars, protective grounding does not have to withstand the load for a long time, its cross-section can be made with excellent parameters.

So the cross-section of the PE conductor is determined in accordance with clause 1.7.126 of the PUE, most simple option is to calculate the value based on the area of ​​the phase conductors:

• For phase wires up to 16mm 2, the grounding cross-section should be the same;
• For models from 16 to 35mm 2, grounding can be at least 16mm 2.
• For lines with a phase wire cross-section of 35 mm 2 or more, the grounding wire must be selected with an area of ​​at least half the phase wire.

This option is the simplest, but it is not always advisable to install a large cross-section conductor on the grounding, as this affects the total cost of cable and wire products. In such cases, it is possible to determine the cross section by calculation:

• S – area of ​​the grounding wire;
• I – value;
• t – response time of protective devices;
• k is a coefficient determined by the materials of current-carrying and insulating elements and temperature.

Connection

Before connecting, it is necessary to mark the main terminals of five or three-wire wires. If you are only doing installation work, you will be able to independently determine which wire to connect where, otherwise you will have to understand the existing wiring. In practice, to determine the location of all types of wires in the connection diagram, use their color designation:

• Phase conductors - have a wide variety of spectrum (brown, red, gray, purple, etc.);
• Grounding conductors are made in yellow-green color, some manufacturers use only bright green color;
• Neutral conductor – blue or cyan.

However, note that not all installers follow the standard procedure or the wire itself may not correspond to the power supply diagram, so before using a ground or phase wire, it is worth ringing them first.

The connection itself is made in such a way as to ensure the most reliable contact with zero or close to it transition resistance. Therefore, the most acceptable is soldering, crimping or tightening under a nut or tip.

It is strictly forbidden to make an electrical connection to the grounding wire by twisting or other non-standard methods. If a copper and aluminum conductor are connected, a brass gasket must be installed between them or they are crimped into a sleeve. Next, the grounding wire is connected from the circuit to the equipment body, metal elements to equalize the potential, or to the corresponding socket contact.

Video to develop the topic

The use of grounded sockets ensures the safety of household members when using electrical appliances. But home craftsmen are in no hurry to update electrical wiring, considering the process of installing grounding outlets difficult. Although the standard scheme of work is quite simple.

We will help you understand this issue. Before you connect a grounded outlet, you need to study it design features and find out the type of wiring in the house. The information in the article is supplemented with visual photo and video instructions for a better understanding of the electrical installation process.

The instructions for any electrical appliance clearly state that it is prohibited to use it without grounding. The main purpose of grounding is to ensure stable operation of complex household devices and protect against electric shock.

According to the PUE clause 1.7.6, grounding is a deliberate connection of one of the elements of an electrical installation with a grounding loop. It is constructed with the purpose of draining currents of values ​​that are damaging or not damaging to humans through the grounding protective conductor into the ground.

If earlier in apartment buildings laid two-core electrical cables, today it is mandatory to use wiring consisting of three cores

In the outdated system, the “neutral” partially served as grounding. The zero was connected to the metal body of the device, and in case of overload it took over it.

The calculation was that if the load was exceeded, current would flow through one of the phases, resulting in a short circuit and, as a consequence, disconnection of a section of the network by an automatic circuit breaker or fuse.

This solution simplified electrical installation work, but carried the risk of electric shock.

When choosing products, pay attention to the size of the inlet holes for the plug and the distance between them. Models from European manufacturers have slightly larger diameters and distances between holes. To avoid mistakes, choose universal models that come with connectors for different types forks

Determining the wiring type

Installation of a grounded socket is carried out in those houses where three-wire wiring is laid. In homes with wiring that includes only two cores, there is no point in installing such a grounding socket, since it will not perform the task assigned to it.

Therefore, the first thing to do is determine what type of wiring is in the apartment. If the electrical wiring in the house is outdated two-wire, it will have to be replaced with a three-wire analogue. Modern three-wire wiring meets all safety standards in all respects.

Replacing wiring is an additional cost item, but the costs will certainly be recouped by the long “life” of electrical appliances and the safety of household members

You can find out whether the electrical panel has a grounding bus from the electrician servicing your entrance or house. The type of wiring is also determined by the number of wires. If a two-core cable is connected to the connection point, then only “phase” and “neutral” are available.

If the socket line is laid from the switchboard with a two-wire cable, you only need to connect a third grounding wire from the electrical panel to each point. But this procedure can only be performed if the shield is equipped with a grounding bus.

Clause 1.7.127 of the current PUE clearly states that the grounding conductor must be made of copper insulated wire with a cross section of at least 2.5 sq. mm.

To introduce a new line of sockets, it is worth using a ready-made three-core cable, already equipped with a ground wire

It is not advisable to lay a cable with a cross-section of 1.5 mm2 from the junction box to the outlet. Indeed, in this case it is impossible to “power” a powerful device from it. For a single-phase network, it is better to take a cross-section with a margin of 2.5 mm 2.

To organize electrical wiring, choose a cable marked VVG, and for fire hazardous premises - VVGng.

The main requirement for a protective conductor is that there should be no disconnecting devices in its circuit. Therefore, it is installed in addition to any fuses, circuit breakers and circuit breakers.

Before installing and grounding the outlet, the first step is to turn off the power to the electrical panel. The technician’s task is to remove voltage from the distribution box feeding the lines with the socket to be replaced.

Wires laid from the electrical panel in an open or closed way are led into the cavity of the socket box. Using an electrical tester, they determine where “phase” is and where “0” is.

End indicator screwdriver alternately immersed in the holes for the plug: if upon contact with the conductor the light on the screwdriver handle lights up - this is a “phase”

But when working with electrical wiring equipped with a grounding wire, it is still better. This is a multifunctional device, even if it is the most simple execution It will also become an indispensable assistant in detecting a broken wire and determining the integrity of radio and electrical components.

Using the device is not difficult. The measuring range is set on the multimeter alternating current above 220 Volts. After which one tentacle is applied to the phase contact, and the second to the “ground” or “0”. When contacting “0”, the voltage of 220V will be reflected on the device; on “ground” the voltage will be slightly lower.

The electricity brought into our homes is an impressive force that can easily kill a person. Therefore, when installing electrical wiring, it is first necessary to take care of the safety of users.

In electrical engineering, the word “grounding” can rightfully be considered a synonym for the word “safety”.

In this article we will talk about why a grounding wire is needed and what requirements it must meet.

Under normal conditions, live parts of electrical equipment are separated from all others by insulation, so touching, say, the body does not pose any threat to the user.

But as a result of an accident, aging of the material or its damage by rodents, the insulation may be broken, as a result of which the housing or other element becomes energized. As soon as you touch it, an electric shock will immediately follow.

Ground wire

In order to weaken or even completely prevent (when connected via an RCD) the effect of current on the user in such a situation, all parts of the equipment that may be energized are connected with a separate wire to a ground loop immersed in the ground. Now, upon contact, the charge will flow through the user only partially, since some of it will go into the ground.

If the device is connected through an RCD (residual current device), then, as already mentioned, electrical injury can be avoided altogether: the device will detect a current leak in the circuit and immediately disconnect it.

Grounding system in residential or industrial building must be present - this is a requirement of the PUE and other regulatory documents. Moreover, a special act must be drawn up to this effect.

Marking

You need to know what color the ground wire is.

Typically, the ground wire, in the form of a separate conductor, is part of the stranded wire that powers an electrical appliance or outlet.

Thus, in a 1-phase network it will be the 3rd conductor, and in a 3-phase network it will be the 5th.

In this case, a special marking is provided for the grounding wire, which makes it possible to distinguish it from the phase or neutral conductors and thus prevents confusion when connecting:

1. Letter. PUEs require that the letters “PE” be applied to the insulation of the grounding wire. The same designation is provided for in international standards. Indication of the cross-sectional area, grade and material is optional.
2. Colored. Domestic and foreign standards specify a combination of yellow and green colors for the ground wire. Some foreign manufacturers of cable products designate such a core only in yellow or only in green.

In addition to grounding conductors, combined conductors are used, which simultaneously perform the functions of zero working and zero protective. They are designated by the letters “PEN” and a combination of blue with yellow or green. One color of the ground wire is the main one, the second is applied in the form of stripes at the ends.

Installation of the ground wire

Thus, it is quite simple to distinguish the ground wire from the neutral wire, which is marked with a blue color and the letter “N,” and from the phase wire (it has brown, black or white insulation, designated by the letter “L”). Color coding has simplified not only the installation of electrical systems, but also such tasks as finding and replacing burnt, broken or overloaded wires.

Some manufacturers paint the phase conductor in other colors: gray, purple, red, turquoise, pink, orange.

Please note that color coding cannot determine whether the network is 1-phase or 3-phase, or whether it is supplied with alternating or direct current. So, the cores and buses of networks direct current(used in construction, electric transport, substations, etc.) are also painted in red (“+”), blue (“-”) and blue (zero bus) colors. In 3-phase networks, phases A, B and C are usually designated yellow, green and red, respectively.

Core designation different colors It is not used in all wires. So, in a 3-core cable of the PPV brand, which seems attractive due to its relatively low cost, you will not find yellow-green insulation, so it is very easy to confuse the cores when connecting.

Working ground

If the marking is not visible or missing, you can determine the grounding conductor in a wire connected to the network using a voltmeter: the voltage is measured between the phase conductor (it is determined by the phase indicator) and each of the two remaining ones. When the probe contacts the “ground”, the value on the device display will be higher than when it contacts “zero”.

You can also measure the voltage between the conductors being tested and any grounded device, for example, an electrical panel housing or a heating battery. If the core is zero, the device will show some small value; if it is “ground”, the display will display zero.

The phase indicator, which is used to determine the conductor connected to the phase, is similar to a screwdriver, only on the handle there is a diode light bulb and a special contact (usually in the form of a ring under the light bulb). To determine the phase, you need to place your finger on this contact and at the same time the tip of a screwdriver on the conductor being tested. If it is energized, the light will light up.

It should be understood that connecting a consumer to a ground wire is not a sufficient safety condition. The wire itself, on the other side, must be connected to the ground loop.

A resident of an apartment in a city high-rise building just needs to find the appropriate contact in switchboard, but the owner of a private house will have to create such a circuit himself.

Usually it consists of metal pins driven into the ground (in the form of an isosceles triangle) connected by reinforcement.

Wire size for grounding

This parameter is primarily determined by the power of the protected equipment. Regulated by the following documents:

1. Chapter 1.7 PUE (“Grounding and protective safety measures”).
2. Chapter 54 in part 5 of GOST R 50571.10-96 “Electrical installations of buildings” (repeats the international standard IEC 364-5-54-80).
3. Appendix RD 34.21.122-87 “Instructions for the installation of lightning protection of buildings and structures.”

Yellow-green color for grounding terminals

The main task when selecting the cross-section of the grounding wire is to prevent it from heating when the maximum current flows (single-phase short circuit) above a temperature of 400 0 C. The maximum cross-section for copper wire is 25 square meters. mm, aluminum - 35 sq. mm, steel - 120 sq. mm. It makes no sense to use wires with a cross-section larger than specified.

When installing a household electrical network for grounding, it is enough to use a wire of the same cross-section as the cores of the supply wire.

Popular brands

Wires of the following brands contain a separate conductor for grounding:

NYM

It is used for connecting stationary installations and is designed for voltages up to 660 V. Can be used in explosive areas: class B1 b, B1 g, VPa - in power and lighting networks; class B1 a - only in lighting.

NYM cable

NYM grounding cable specifications:

• core material: copper;
• core type: single-wire;
• there is an intermediate shell;
• the cores have standard color markings.

Cutting and installation are very easy.

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VVG

The cables of this brand have the following in common:

• core material: copper;
• core type: stranded (twisting class - I or II);
• insulation and sheath material: PVC (color-coded);
• there are two steel strips that serve as armor;
• the outside of the cable is wrapped in fiberglass and coated with a bitumen compound.

The outer cover of the VVG cable does not spread combustion and is not destroyed under the influence of ultraviolet radiation. Versions are available with the number of cores from 1 to 5.

If the wiring is already done with 2-wire or 4-wire cable, the ground wire can be installed separately.

The following brands of cables are suitable for this:

PV-3

Multi-wire single-core copper cable. Insulation - single-layer, PVC. During installation, it should be easily removed from the core. If the insulation sticks to the copper, it means that violations were committed during production or storage.

The PV-3 cable is available in cross-sections from 0.5 to 240 sq. mm.

PV-6-ZP

Like the previous one, it is a copper stranded single-core, but it also has some differences:

• the core class is higher (No. 6 versus No. 2, 3 and 4 for PV-3);
• the insulation is made of a transparent type of PVC, which allows you to visually monitor the condition of the core;
• withstands temperatures from -40C to +50C;

PV6-3P is not afraid of alternating bends (at an angle of up to 180 degrees and a bend radius of at least 50 mm).

ESUY

This cable is produced in Germany. Designed for use as a grounding wire in short circuit protection systems. Capable of withstanding high temperatures and has a particularly durable and chemical-resistant shell.

Since the ESUY cable is originally intended for grounding, the rated voltage for it is not standardized.

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