To ensure the safety of people, protective grounding electrical installations.

Protective grounding/ in a private house will minimize the amount of interference that occurs within the electrical network. In addition, a properly executed protective circuit grounding/ grounding the level of electromagnetic radiation, which negatively affects the physical condition of a person and his well-being, will significantly decrease.

Under protective grounding understand a system of conductors made of metal, which is immersed in the ground. There are certain rules by which this stage is carried out. For example, this applies to geometric shapes. It should be a triangle with equal sides.

Installation (installation) contour grounding/ grounding and zeroing of electrical installations.

Mounting (installation) contour grounding/ grounding electrical installations - a deliberate electrical connection of its body with a grounding device.

Protective grounding There are two types of electrical installations: protective grounding and zeroing, which have the same purpose - to protect a person from electric shock if he touches the body of the electrical installation or its other parts that are energized.

Mounting (installation) contourgrounding/ grounding - deliberate electrical connection of a part of an electrical installation with a grounding device in order to ensure electrical safety. Protective circuit grounding/ groundingdesigned to protect a person from touching the body of the electrical installation or its other parts that are energized. The lower the resistance of the grounding device, the better. To take advantage of the protective circuit grounding, you need to buy sockets with a grounding contact.

In the event of an insulation breakdown between the phase and the body of the electrical installation, its body may be energized. If a person touched the body at that time, the current passing through the person is not dangerous, because its main part will flow through the protective circuit grounding, a grounding has very low resistance. Protective circuit grounding/ grounding comprises grounding conductor and grounding conductors.

Grounding conductor - the conductive part of the protective circuit grounding(or a collection of interconnected conductive parts) in contact with earth directly or through an intermediate conductive medium.

Grounding conductors are one of the constituent parts of the protective circuit grounding. Design grounding/ groundingWith Luzhit for connection with grounded elements of electrical installations. As well as for grounding conductors, as conductors grounding it is possible to use various metal structures of buildings and structures, while observing the instructions of the project and ensuring the continuity and sufficient conductivity of the circuit circuit grounding.

The material of the conductors in the protective circuit grounding.

For specially laid conductors grounding steel is usually used. Only for flexible jumpers to movable pantographs and in other cases where increased flexibility is needed or special requirements for conductivity are imposed, in the protective circuit grounding when making, copper is used.

Quick and complete shutdown of damaged equipment.

Zeroing - a deliberate electrical connection ( mounting) parts of the electrical installation that are not normally energized with a deadly grounded neutral with a neutral wire. This leads to the fact that the short circuit of any of the phases on the body of the electrical installation turns into a short circuit of this phase with a neutral wire. The current in this case arises much greater than when using a protective grounding. Quick and complete shutdown of damaged equipment is the main purpose of zeroing.

Distinguish between a zero working conductor and a zero protective conductor.

1. The zero working conductor is used to power electrical installations and has the same insulation as other wires and a sufficient cross section for the passage of the working current.
2. Zero protective conductor is used to create a short-term short-circuit current for the operation of the system protection grounding and quick disconnection of the damaged electrical installation from the mains. As a neutral protective wire, steel pipes of electrical wiring and neutral wires that do not have fuses and switches can be used.

How is it done installation(mounting) zeroing?

Zeroing does not play the role of a protective circuit 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 circuit. grounding the entire building.

Why do you need to do mounting contour grounding/ grounding for gas boiler.

grounding a gas boiler with the simultaneous installation of an RCD is a necessary and indispensable condition for the arrangement of a gas heating system. In this case, the protective measures of the design grounding/ grounding are aimed not only at preventing electric shock to a person and eliminating damage to electrical equipment, but also at protecting against a possible fire, and hence an explosion.

Gas connection heating equipment according to the safety rules, it is carried out only if there is a protective circuit grounding meeting the required standards. An additional requirement is the mandatory installation (mounting) RCD, which disconnects the device from the network in the event of a short circuit. With respect to this, several important questions arise.

What needs to be done mounting protective circuit grounding?

Run mounting protective circuit grounding/ grounding and ground a gas boiler in a private house is necessary no matter how long it has been in operation.

This is required due to the fact that static voltage is generated on the boiler body. As a result, under certain conditions, the following may occur:

- failure of automation. Electronic devices have a board that is sensitive to voltage drops. Its replacement can be very expensive;

• - risk of fire. The main reason to avoid mounting protective circuit grounding/ grounding for a gas boiler, since natural gas is an explosive substance, for the ignition and explosion of which just one random spark is enough.

Due to the fact that the body of the gas boiler is metal, it accumulates static electricity. The static that accumulates on the boiler casing creates a strong electric field that can easily disable the board responsible for controlling the boiler. Such a board is almost the most expensive part of a gas boiler, and its failure can lead to sad consequences.

In addition, due to the accumulated static electricity on the casing, touching the boiler will bring discomfort, so you still have to do mounting contour grounding/ grounding for gas boiler.

Mounting (installation) protective circuit grounding/ grounding for a gas boiler, it is primarily necessary for your own safety. Costs and difficulties associated with the installation of the circuit structure grounding fully paid off even by the fact that the owners will have the opportunity to avoid costly replacement of the automation board. But more importantly, with the help of such simple measures, it will be possible to prevent the occurrence of potentially life-threatening situations. That's why installation (mounting) protective circuit grounding/ grounded is necessary, both for the installation of new and for previously installed equipment.

How to do it right mounting protective circuit grounding/ grounding for gas boiler.

First you need to take into account that the requirements that apply to how to connect the boiler to the protective circuit grounding, more stringent than in the case of conventional electrical appliances also needing this device. Moreover, not only the total resistance of the circuit design is checked grounding, but also the specific conductivity of the soil.

To produce mounting protective circuit grounding/ grounding required for a gas boiler.

In this case, you will need a welding machine, a corner with the required section. The design of the protective circuit grounding/ grounding in the form of a triangle or an inverted letter “Sh”, it will be necessary to bury it in the ground to a depth of at least a meter.

Selection of earthing conductors to perform mounting contour grounding/ grounding .

Before executing mounting contour grounding/ grounding , you must select the type of ground electrode that you will use.

The grounding conductor is an integral part of the grounding device (protective circuit). grounding/ grounding, which is a single ground electrode that is in direct electrical contact with the ground. They are divided into two types: natural grounding and artificial. The dispute about which type is better to use when installing the ground loop / grounding has not yet been resolved.

Mounting (installation) natural grounding devices.

Natural grounding devices used for grounding.

Foundation ground electrode is a natural grounding, which is installed in the concrete foundation of the building. It is a steel reinforcement interconnected by a potential equalization conductor or a plate grounding. The foundation ground electrode is laid in a reinforced concrete foundation at the time of its installation. For it to function as grounding external leads must be drawn from the foundation to connect the down conductor.

natural elements grounding most often used to ground, make mounting contour grounding protective grounding natural type. For example, metal parts (reinforcement) included in the arrangement of reinforced concrete elements, for example, the foundations of power transmission lines and substations, as well as the foundations of buildings. In addition, as a natural grounding various types of metal underground communications can be used, for example, pipelines, armor or cable sheaths. In some cases, it is allowed grounding use ground communications, for example, railroad tracks.

It is worth remembering that the natural contour grounding must be connected to the gas boiler with at least two grounding conductors (the conductor that connects the parts of the gas boiler to the elements grounding).

By the way, as a natural contour grounding It is strictly forbidden to use flammable liquid pipelines, pipelines that are covered with corrosion insulation, sewage pipelines or central heating pipelines.

Than using natural elements grounding better than artificial ones?

Natural contour elements grounding it is permissible to use if they are able to ensure the fulfillment of absolutely all the requirements that apply to grounding structures.

artificial elements grounding.

The artificial elements grounding must be used when it is necessary to significantly reduce the currents that through natural elements grounding will go to the ground.

This means that in most cases, doing mounting protective circuit grounding, You can only use natural elements grounding without resorting to artificial ones. With this constructive step, it is possible to significantly reduce the amount of materials required for the construction of the circuit. grounding, in addition, financial and labor costs will be reduced, and the operation of the grounding device will be much easier than when using artificial grounding.

In case you decide to do mounting contour grounding/ grounding and use exclusively natural elements grounding for the safety of your home, the electric currents flowing through the ground wire should not exceed the allowable for each component of the grounding device.

Grounding straps.

Grounding strap clamps for connecting one or two conductors to a protective circuit grounding and inclusion of pipes in the protective system grounding and functional potential equalization according to DIN VDE 0100-410/540, with continuously adjustable tension.

clamp grounding- this is a metal screed with a terminal block, which allows you to transfer the unexpected potential of the electric field to the conductor grounding, thereby preventing a person from getting an electric shock and protects the device on which the clamp is fixed from damage.

clamp grounding pipes are widely used both at gas and oil industry facilities and in housing construction. It is designed for mounting on pipes made of steel or copper.

Artificial grounding devices used to install a protective circuit grounding.

artificial elements grounding/ artificial grounding are made of several single ground electrodes (electrodes grounding), hammered into the ground and interconnected by a strip of steel strip. as electrodes grounding pieces of angle steel 50 X 50 x 5 are used, 2 5 - 3 m long, located at a distance of 2 5 - 5 m from each other, depending on local conditions. Driving ground electrodes, producing mounting with the use of artificial grounding devices, at a distance of less than 25 m from each other, cannot be recommended due to the deterioration of the conditions for the spreading of currents in the ground.

Mounting protective circuit grounding using artificial grounding devices.

artificial elements grounding.

1. Recessed elements - strips or round steel contour chain grounding laid horizontally on the bottom of the pit or trench in the form of extended elements;
2. Vertical contour elements grounding- steel screw-in rods with a diameter of 12-16 mm, angle steel with a wall thickness of at least 4 mm or steel pipes (substandard with a wall thickness of at least 3.5 mm).

The most common artificial grounding performed using vertical electrodes combined by connecting strips into a single structure grounding, to which electrical installations are connected with the help of grounding conductors.

Grounding device electrodes are made of steel pipes (wall thickness of at least 3-5 mm), steel corner profiles (shelf thickness of at least 4 mm), round (diameter of at least 10 mm) or rectangular (cross-section of at least 48 mm2) steel bars. In electrical installations with voltages up to 1 kV and higher with an insulated neutral, the conductivity of the grounding conductors must be at least 1/3 of the conductivity of the phase conductors.

In mountainous areas, in the presence of aggressive underground waters of deep origin, saturated with gases that can destroy the artificial grounding, a special design of the ground electrode is used. Circuit electrode grounding It is made in the form of a cylinder made of roofing steel 2 m high, 150-180 mm in diameter, filled with an electrode mass tightly enclosing a current-carrying rod made of round steel. Electrode mass, in the electrode grounding, of the usual composition used for electrodes of arc furnaces, is a good conductor of electric current and at the same time an insulating material from moisture, resistant to aggressive waters of carbonic or alkaline nature.

artificial elements grounding should be used only when the possibility of using a closely located natural grounding.

Electrodes and ground conductors - structural elements grounding must not have color, must be cleaned of rust, traces of oil, etc. If the soil is aggressive, then in the structure grounding use galvanized electrodes. Immersion of electrodes grounding into the ground is carried out with the help of special devices.

Connecting Parts of Contour Elements grounding between themselves, as well as the connection of grounding conductors with grounding conductors, in the presence of sources of electricity, should be performed - by welding. The length of the overlap when welding should be equal to twice the width of the strip for rectangular strips or six diameters for round steel. Welds in construction grounding located in the ground, it is necessary to cover with bituminous varnish to protect against corrosion.

To piping elements grounding attached with clamps. If there are valves or bolted flange connections on the pipes, bypass jumpers are made.

In outdoor installations, as well as in damp rooms with caustic vapors or gases, the bolted joints of the structure grounding protect with grease (marine AMS is recommended), in internal installations they are coated with neutral vaseline or glyptal varnish.

• Mounting (installation) grounding devices of the protective circuit grounding consists of the following operations:
  • installation of chain elements grounding;
  • laying grounding conductors of the circuit grounding;
  • connecting elements in a chain grounding together;
  • connection of grounding conductors to the elements of the contra-protective grounding and electrical equipment.

To do mounting contour grounding/ grounding for a grounding device, it is necessary to perform several stages of installation work.

In welding of studs in the structure grounding most often fasteners with diameters M3-M8 are used, although there are especially powerful studs M10 and more, which are used to create strong connections with very thick metals.

Preparation of material for mounting the circuit grounding.

For structural elements grounding, steel is most often used, in view of its relatively cheap cost, although the best option is an electrode made of copper or copper-plated steel.

One of the most important
indicators, when choosing an electrode in the design grounding is its cross-sectional area. When using a rectangular profile or corner, the cross-sectional area should be from 150 square millimeters. The steel pipe should be a minimum diameter of 32mm, not less than 3.5mm with wall thickness. The ground electrode must be at least 2 meters long. Grounding conductors should not have any coatings that interfere with contact grounding with soil.

Mounting (installation) tire design grounding/ grounding for a private house with an internal ground loop.

The main ground bus (GZSH) of the design of the protective grounding should usually be copper. It is allowed to use the main earthing bar made of steel. The use of aluminum tires in construction grounding not allowed.
In design grounding, to the bus, it must be possible to individually access and disconnect the conductors connected to it.

Protective loop system designations grounding.

System grounding differs in connection schemes and the number of zero working and protective conductors.

The first letter in the designation of the contour system grounding, determines the character grounding power supply:
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 in the designation of the circuit system grounding, determines the character grounding open conductive parts of the electrical installation of the building;
T - direct connection of the open conductive parts of the electrical installation of the building with the ground, regardless of the nature of the connection between the power source and the ground;
N - direct connection of open conductive parts of the electrical installation of the building with a point grounding power source.

The letters following through the dash behind N determine the method of constructing the zero protective and zero working conductors:

• C - the functions of the zero protective and zero working conductors are provided by one common PEN conductor.
• S - functions of zero protective PE and zero working N conductors are provided by separate conductors.

Requirements applied to quality at your facility.

In order for the gas services not to make any claims against you, the resistance grounding, in the protective grounding Your gas boiler must have:

• - for ordinary clay soil, loop resistance grounding, must be up to 10 ohms (for a standard voltage of 220 V or for a three-phase current source with a voltage of 380 V);
• – for sandy soil, resistance grounding- no more than 50 Ohm (for a standard voltage of 220 V or for a three-phase current source with a voltage of 380 V).

Protective circuit grounding for a gas boiler is an integral part of the home heating system, so this procedure must be done as quickly as possible.

After the installation of the structure grounding draw up an act (protocol) for hidden work and indicate on the drawings the bindings of grounding devices to stationary landmarks.

Insulation control of wires in a structure grounding.

To prevent accidents from electric shock, it is necessary to monitor the condition of the insulation of the wires of electrical installations connected to the protective circuit. grounding. The condition of the wire insulation is checked in new installations, after reconstruction, modernization and a long break in work.

Preventive control of wire insulation is carried out at least 1 time in 3 years. The insulation resistance of the wires is measured with a megohmmeter for a rated voltage of 1000 V in the areas with the fuse-links removed and with the current collectors turned off between each phase wire and the neutral working wire, and between each
two wires. The insulation resistance must be at least 0.5 Mohm.

How to check the protective circuit grounding/ grounding.

Conducting mounting protective circuit grounding it is necessary to take into account the requirements that apply to such a device.

Depending on the situation applied normative documents PUE 1.7.103 or PUE 1.7.59, the requirements for resistance may vary significantly. You should find out exactly what indicators will be used to evaluate the quality of the protective structure made. grounding/ grounding.

For private houses, with a connection to the mains 220 Volt / 380 Volt, it is necessary to have a local grounding with a recommended resistance of not more than 30 ohms.

• When connecting a gas pipeline to a house, the standard requirement for grounding. However, due to the use of hazardous equipment, local grounding with a resistance of not more than 10 ohms.
• 2. Specific conductivity. Also, certain requirements are imposed on this criterion. So the maximum allowable value for ordinary soil is not more than 50 ohms.

Specialists of the Pushkin Energy and Gas Company will professionally conduct electric installation work to install a grounding device and make mounting protective circuit grounding/ grounding which will protect you and your loved ones from electric shock.

Due to the presence of an electrical laboratory and equipment, our specialists will immediately conduct control electrical measurements of the protective circuit grounding and draw up an act grounding/ resistance measurement protocol grounding.

In the modern world, it is almost impossible to imagine life without technology that works with electricity. We can say that it has become quite firmly established in the lives of many, and without it it is difficult to imagine a “normal” life. But it happens that the equipment you love and need can suddenly turn into a source of danger to life. It is to avoid such situations that you need to use a ground loop. (Fig. 1)

Almost all modern homes are equipped with all sorts of electrical appliances that are part of our daily lives. But if the insulation is broken, it can turn from an indispensable assistant into equipment that poses a real threat to life. To prevent it from arising, a ground loop is arranged in the houses.

What is a ground loop for?

Grounding is a device of a special design that will be connected to the ground (ground). In this case, electrical appliances are included in such a connection, which in their normal state are not energized. But in case of violation of operating conditions or other reasons that led to damage to the insulation, it can occur. Therefore, it is so important to comply with the grounding standards of the ground loop.

The whole point is as follows - the current always tends to where there is the least resistance. So in the event of a violation in the equipment, current flows out to the body of the product. The equipment begins to work intermittently and gradually becomes unusable. But something else is much worse - when you touch such a surface, a person receives such a discharge that he simply dies.

But when using a - ground loop, the following will occur. The voltage will be shared between the existing circuit and the person. That's just the ground loop in this case will have less resistance. And this means that although a person will feel inconvenience, all the same, the entire main current will go through the circuit into the ground.

Important! When arranging a ground loop, it will be important to remember and observe everything necessary for arranging it with minimal resistance.

Ground loop - types and its device

Basically, metal rods are used for grounding, which play the role of electrodes. They are interconnected and deepen a sufficient distance into the ground. This design is connected to the shield installed in the house. For this, a strip of metal of the required thickness is used. (fig.2)

The very distance to which the electrode is immersed directly depends on the height of the location. ground water. The higher their occurrence, the higher the grounding system. But with all this, its removal from the desired object is from one meter to ten meters. This distance is important condition and must be strictly observed.

The location of the electrodes is often in the form of a geometric figure. Often it is a triangle, line or square. The shape is affected by the area that must be covered and ease of installation.

Important! The grounding system is necessarily located below the level of soil freezing that exists in a particular place.

The main types of ground loops

So there are two main types of technological solutions. These are ground loops - deep and traditional.

So with the traditional method, the location of the electrodes is as follows - some are located horizontally, and the rest are vertical. The first electrode is a steel strip, and the second are, respectively, metal rods. All of them must have valid values ​​for their size.

It must be borne in mind that the place for the device of the kennel must be selected from the fact that it should be less crowded. The best for this will be the shady side with constant soil moisture.

But this ground loop has its drawbacks:

• rather difficult and physically heavy device;
• the metal products that make up the circuit are subject to corrosion, which not only destroys it, but will burn them to cause a deterioration in conductivity;
• since it is located in the upper part of the earth, it is very dependent on environmental parameters, which can change its conductive characteristics.

The deep method is much more efficient than the traditional one. It is produced by specialized manufacturers. And it has a number of advantages:

• complies with all established standards;
• service life is significantly longer;
• does not depend on the environment, due to the depth of occurrence;
• installation is quite simple.

It must be borne in mind that after the device of any type of ground loop, it is necessary to check its compliance with all requirements and reliability. For this purpose it is necessary to invite specialized experts. They must be licensed to carry out such activities. After verification, an appropriate conclusion is issued. It is necessary to bring a passport to the ground loop, attach a test report and a permit for use to it. (Fig. 3)

Important! It is impossible to save on materials when constructing a ground loop (Fig. 4). Otherwise, his work will be completely reduced to zero.

External ground loop

This system serves as a transformer substation and is closed. Consists of a small number of electrodes. They are located vertically. Horizontal grounding, it is made, and steel strips 4 * 40 mm.

The ground loop should have a resistance of 40 m, no more, and the earth should be maximum 1000 m / m. Currently, according to the rules, you can increase the values, but not more than ten times for the ground. From this we can conclude that in order to achieve a value of 40 m, it is necessary to vertically install eight electrodes of five meters each. They must be made from a circle with a diameter of 16 mm. Or you can use ten three meters, when using a corner made of steel 50 * 50 mm.

The outer contour is removed from the edge of the building by more than a meter. Elements located horizontally are buried in a trench at a distance of 700 mm from the level of the soil surface. The strip has a rib.

Thus, it is clear that existing norms should be strictly guided. So the ground loop of the PUE is reflected in chapter 1.7. It is also necessary to keep track of all changes in requirements, which can happen quite often.

The main element of ensuring the safety of electrical installations is protective grounding. Related systems: automatic protective switches, fuses, lightning protection - cannot function in its absence, and become useless.

What is grounding

This is a complex consisting of metal structures and conductors, which provides electrical contact between the electrical installation housing and the physical earth, that is, with the ground. The system starts with a ground electrode: a metal electrode grounded into the ground. These elements cannot be single; for reliability, they are combined into a ground loop.

How it works

The external ground loop (which is located directly in the ground) is connected using a reliable conductor to the internal loop in the room, or to the ground shield. Further, with the help of an internal network of protective conductors, a connection is made to the housings of electrical installations, and grounding contacts on switching devices (switchboards, boxes, sockets, etc.).

Devices that generate electricity also have a grounding system to which the neutral bus is connected. In the event of an emergency (the phase is connected to the body of the electrical installation), an electrical circuit occurs between the phase conductor and the neutral bus along the ground line. The current in the emergency circuit increases spontaneously, the residual current device (circuit breaker) trips or the fuse link blows.

The result of a working system:

• the power cable does not ignite (fire hazard);
• the possibility of electric shock when touching the emergency housing of the electrical installation is prevented.

The resistance of the human body is ten times higher than the ground resistance. Therefore, the current strength (in the presence of a phase on the body of the electrical installation) will not reach a life-threatening value.

What is grounding

1. External ground loop. It is located outside the premises, directly in the ground. It is a spatial structure of electrodes (ground electrodes) interconnected by an inseparable conductor.
2. Internal ground loop. Conductive bus located inside the building. Covers the perimeter of each room. All electrical installations are connected to this device. Instead of an internal circuit, a ground shield can be installed.
3. Grounding conductors. Connecting lines designed to connect electrical installations directly to the ground electrode system, or to an internal ground loop.

Consider these components in more detail.

External, or external contour

The installation of the ground loop depends on the external conditions. Before starting the calculation and making a design drawing, it is necessary to know the parameters of the soil in which the ground electrodes will be installed. If you have built a house yourself, these characteristics are known. Otherwise, it is better to call surveyors to get an opinion on the ground.

What are the soils, and how do they affect the quality of grounding? Approximate resistivity of each soil type. The lower it is, the better the conductivity.

• Plastic clay, peat = 20–30 Ωm m
• Plastic loam, ash soils, ash, classic garden soil = 30–40 Ohm m
• Chernozem, shale, semi-hard clay = 50–60 Ohm m

This is the best environment to install outer contour grounding. Current spreading resistance will be quite low even at low moisture content. And in these soils, the natural humidity is usually above average.

• Semi-solid loam, mixture of clay and sand, wet sandy loam - 100–150 Ohm m

The resistance is slightly higher, but with normal humidity, the grounding parameters will not go beyond the standards. If prolonged dry weather sets in in the installation region, it is necessary to take measures to forcibly moisten the installation sites of the ground electrodes.

• Clay gravel, sandy loam, wet (permanent) sand = 300–500 ohm m

Gravel, rock, dry sand - even with high overall humidity, grounding in such soil will be ineffective. To comply with the regulations, it is necessary to install deep ground electrodes.

Important! Incorrect calculation of the ground loop, ignoring the parameters often lead to sad results: electric shock, equipment failure, cable fire.

Many owners of objects, saving "on matches", simply do not understand why a ground loop is needed. Its task, when connecting the phase to the ground, is to ensure the maximum value of the short circuit current. Only in this case, the residual current devices will quickly operate. This cannot be achieved if the current flow resistance is high.

Having decided on the soil, you can choose the type, and most importantly, the size of the ground electrodes. Preliminary calculation of parameters can be performed using the formula:

The calculation is given for vertically installed earthing switches.

Deciphering the formula values:

• R0 - the resistance of one ground electrode (electrode) obtained after calculation in ohms.
• Req - soil resistivity, see information above.
• L is the total length of each electrode in the loop.
• d is the diameter of the electrode (if the section is round).
• T is the calculated distance from the center of the electrode to the earth's surface.

By setting known data, as well as changing the ratio of values, you should achieve a value for one electrode of the order of 30 ohms.

If the installation of vertical grounding is not possible (due to the quality of the soil), it is possible to calculate the resistance value of horizontal grounding.

Important! Installation of a horizontal circuit is more laborious and is associated with increased material consumption. In addition, such grounding is highly dependent on seasonal weather.

Therefore, it is better to spend more time hammering vertical rods than to follow the barometer and air humidity.

And yet we give the formula for calculating horizontal ground electrodes.

Accordingly, the decoding of additional values:

• Rv - the resistance of one ground electrode (electrode) obtained after calculation in ohms.
• b - the width of the electrode - ground electrode.
• ψ - coefficient depending on the weather season. The data can be found in the table:

• ɳГ is the so-called demand factor for horizontal electrodes. Without going into details, we get the numbers from the table in the illustration:

A preliminary calculation of the resistance is necessary not only for the correct planning of material purchases: although it will be a shame if you do not have enough to complete the work, a couple of meters of the electrode, and several tens of kilometers to the store. A more or less neatly drawn up plan, calculations and drawings will be useful for solving bureaucratic issues: when signing documents on the acceptance of an object, or drawing up technical specifications with an energy sales company.

Of course, no engineer will sign papers only on the basis of even beautifully executed drawings. Spreading resistance measurements will be made.

Work technology

We choose the location of the ground electrodes. Of course, not far from the house (object), so that you do not have to lay a long conductor, which will have to be mechanically protected. It is desirable that the entire area of ​​\u200b\u200bthe contour is located in the territory that you control (you are the owner). So that at one fine moment, your protective "earth" is not dug up by a drunken excavator. So we will not hammer the pins behind the fence.

A garden is suitable (with the exception of a potato bed), a front garden, a flower bed near the house. Cultivated areas are preferred, they are regularly watered. And additional moisture in the ground will benefit grounding. If your soil has low resistivity, you can install grounding on the site, which will then be covered with asphalt or tiles. Under artificial turf, the earth does not dry out. And the risk of damaging the ground loop is minimal.

Of course, it is necessary to take into account future plans. If a garage with a viewing hole appears at the installation site of the circuit in a year, it is better to immediately choose a quieter place.

Depending on the shape of the site, we choose the order of the electrodes: in a line, or in a triangle.

Important! Regardless of the location, there must be at least three vertical ground electrodes.

If a triangle is selected, we mark out a platform of the appropriate shape with sides of 2.5–3 meters. We dig a trench in the shape of an equilateral triangle to a depth of 70–100 cm, a width of 50–70 cm. We know that all ground electrodes are interconnected. The conductor must be deepened to a distance of at least 50 cm, taking into account the minimum ground level (for example, digging up beds). If a coating is laid on top, its thickness is not taken into account. Only clean soil.

You can select the entire soil, not only along the perimeter of the trench. A triangular pit with a depth of 0.7–1.0 m will be obtained. The finished contour can be covered with soil with low resistivity. For example, ash or ashes. Salts will penetrate into the ground, and will help reduce the overall resistance to current spreading.

After that, at the corners of the pit (trench), we begin to clog the electrodes.

Grounding parameters (we consider the vertical arrangement)

• Steel without galvanized coating:

Circle - diameter 16 mm.

Pipe - diameter 32 mm.

Rectangle or corner - cross-sectional area 100 mm².

• Steel galvanized

Circle - diameter 12 mm.

Pipe - diameter 25 mm.

Rectangle or corner - cross-sectional area 75 mm².

Circle - diameter 12 mm.

Pipe - diameter 20 mm.

Rectangle or corner - cross-sectional area 50 mm².

The soil should tightly fit the metal surface of the ground electrode. It is forbidden to paint the electrodes!

But what if, according to calculations, the length of each of the three electrodes exceeds 1.5–2 meters? There are little secrets.

We connect the electrodes with a conductor. If the reinforcement is steel, welding is best. Copper rods are connected with a bolted tie, the conductor must have a cross section of at least 30% of the cross section of the electrodes.

After assembling the circuit, we measure the resistance to current spreading. Requirements for the ground loop for individual housing - 10 ohms. It is better to entrust the measurement to certified specialists who have the appropriate equipment. Moreover, when receiving technical specifications from power engineers, you still have to provide a grounding system for measurements. If the resistance is above the norm, add electrodes and weld them to the circuit. Until we get the norm.

Ground loop inside the object

As a rule, this is a steel tire laid open way along the inner surface of the walls, near the floor.

In individual residential buildings, the installation of an internal ground loop is not carried out. Due to the low hazard class of the premises, and a small number of electrical installations. Instead of an internal circuit, a grounding shield, or main grounding bus (GHSh), is installed.

The shield is connected either to the internal circuit (as in the illustration), or with the help of a conductor to the external ground circuit. Protective ground conductors are routed directly from the shield to electrical installations. Often, instead of the grounding shield, the “PE” terminal block can be used directly in the entrance shield of the apartment.

Outcome

We examined in detail what a ground loop is, why it is needed, and what it should be like according to the PUE. Self-installation does not reduce responsibility: your life and the lives of household members depend on compliance with safety requirements.

Related videos

Recently, a lot of useful electrical appliances have appeared that make our life as comfortable as possible. For example, if gas is not supplied to your country mansion, then you can heat the premises using ceramic heaters, cook food on an electric stove, and install a boiler to heat water. But the more devices you use, the higher the likelihood of electric shock when in contact with them. To protect your life, you need to make grounding devices operating from the network. Unlike multi-storey buildings, the implementation of this electrical safety measure in a private house is not particularly difficult. Therefore, today we will talk about the grounding device, give its calculation and step by step instructions by installation.

Purpose of protective earthing

A properly made ground loop in a private house will save you from electric shock when there is an insulation breakdown on the device case

When the insulation of the supply wire breaks down, a potential appears on the metal case of an ungrounded device. If you touch such a device, you can get an electric shock. At best, you will be “pinched” a little, and at worst, you will get serious injuries that are incompatible with life.

Why does a person get stressed? Current follows the path of least resistance. And he tends to the ground, because it has a large electrical capacity. Therefore, when in contact with a faulty device, your body (having a resistance of the order of 1 kOhm) becomes the only conductor. But what if we “offer” the current an easier path by connecting the equipment case to the ground with a metal conductor of less resistance? In this case, most of the charge will go through it.

In addition to ensuring safety, grounding allows you to:

• stabilize the operation of electrical installations;
• protect devices from power surges;
• reduce network interference, as well as the intensity of electromagnetic radiation of increased frequency.

Important: It is necessary to ground all consumers operating from networks with a voltage of more than 42 V AC and 110 V DC.

Device

The ground loop consists of two elements: the ground electrode itself and conductors. The latter are any parts of the device that connect electrical equipment to the circuit. As a rule, these are cables with yellow-green insulation and a busbar located in a switchboard (RShch). The grounding conductor includes electrodes and other circuit elements that are in direct contact with the ground and ensure the spreading of an electric charge.

Grounding conductors are natural and artificial. In the first case, the role of the grounding device is performed by the buried parts of the building structures of buildings, and in the second, a specially made conductor. According to the Electrical Installation Rules (PUE), preference should be given to natural grounding conductors. For example, in a private house it could be:

• well casing;
• metal pipelines;
• armor of power cables;
• all kinds of metal structures on the street, for example, a fence;
• buried reinforced concrete parts of the building (columns and foundations).

If the resistance of natural grounding conductors is less than the established norms, then it is allowed to use artificial ones. It is about them that we will talk today.

How to calculate

First of all, it is necessary to determine the conductivity of the ground electrode. That is, it is necessary to choose an electrode so that the resistance of the circuit is within the normal range. According to the provisions of the PUE, the maximum values ​​​​of the spreading resistance of ground electrodes are as follows:

• 2 Ohm - for line voltage 660/380 V of a three-phase / single-phase current source;
• 4 Ohm - for 380/220 V;
• 8 Ohm - for 220/127 V.

The conductivity of the protective structure depends on the area of ​​its contact with the ground, as well as the resistivity of the soil. The larger the pins (electrodes), the larger their surface area and, consequently, the higher the conductivity and efficiency of the circuit. At the same time, to achieve good characteristics of the grounding device, it is more correct to increase the length of the electrodes, and not the cross section. This is very important when creating contours in hard soils such as sandstone, rocky ground and others.

So, to determine the conductivity of one electrode of circular cross section, the following formula is used:

R1 = ρ(ln(2L/d) + 0.5ln(4T+L)/(4T-L))/2ПL,

where d and L are the diameter and length of the electrode, T is half the depth of the pin, ln is the natural logarithm, P is a constant (3.14), ρ is the resistivity of the soil (Ohm × m).

Soil resistivity is also an important parameter. The larger it is, the worse the conductivity of the ground loop will be. The value of resistivity for a certain type of soil can be found in publicly available tables.

The lower the soil resistivity, the better the contour will be

This is interesting: With the onset of cold weather, the resistance of the earth increases sharply. The reason for this is frozen water, because ice is a dielectric. Therefore, in areas with permafrost soils, the depth of grounding should be greater than in latitudes with a warmer climate.

When installing a ground loop consisting of several electrodes, the calculation changes slightly. First, the resistance of each individual pin is determined using the above formula. Then the obtained indicators are summed up taking into account the so-called "utilization rate". The calculation formula here is:

R = R1/(KN), where R is the total loop resistance, N is the number of electrodes, K is the utilization factor, R1 is the resistance of one pin.

The value of K depends on the distance between the electrodes. Moreover, the further apart the pins are located, the greater this coefficient will be. Electricians also recommend placing the electrodes at a distance of 2.2 of their length. In this case, K can take the following values:

• when using two electrodes - 0.9–0.92;
• three - 0.85–0.88;
• five - 0.79–0.83.

To determine the depth of the bars, you need to use the formula:

N = R1 / KR, where R is the previously obtained design resistance of the circuit, R1 is the resistance of one pin, K is the utilization factor.

As for the horizontal parts connecting the pins into one ground loop, their conductivity is not calculated here.

Choosing a contour scheme for a private house

The ground loop, made according to the "triangle" scheme, is the most reliable

There are many schemes of ground loops, and the most popular of them is the arrangement of electrodes in a triangle (closed circuit). The pins are driven into the ground at three vertices of an equilateral figure and connected on top with a horizontal strip. The main advantage of such a scheme is that if one of the ground electrodes fails, the circuit will continue to function.

The pins can also be driven in one row (linear scheme). This option is used if one narrow strip of land is allocated for grounding installation. The stakes are interconnected by one or two metal tires. On the one hand, the installation of this scheme is much easier to perform, since there is no need to dig three trenches. However, this variation of the contour is less reliable. The fact is that if at least one horizontal jumper fails, the efficiency of the entire system deteriorates sharply.

The choice is yours, but of the two above schemes, it is better to give preference to a closed ground loop configuration. If you decide to make groundings in a linear pattern, then add several electrodes and horizontal stripes. This will increase the reliability of the circuit.

Materials and tools for self-production

Use rods made of materials with high electrical conductivity as electrodes

After completing the calculation and selecting the ground loop scheme, you can proceed to the purchase of materials. To create a structure with your own hands you will need:

• black steel rods with a diameter of 16 millimeters or more - vertical electrodes;
• steel strip (tire) with a section of 5 × 40 millimeters - a horizontal ground electrode;
• copper wire with a cross section of at least 10 square millimeters - connecting the circuit to the switchboard;
• bolts with a diameter of 10 mm;
• black exterior paint or mastic.

Important: Structural rebar is not suitable for use as earth rods. The fact is that the outer layer of such rods is red-hot, so the electric current is distributed unevenly over the cross section. And this, in turn, leads to the destruction of the metal. In addition, the reinforcement is subject to corrosion.

The quantity and dimensions of materials are selected in accordance with the calculated data.

In addition, we will need the following tools and equipment:

• shovel (development);
• welding machine (connection of circuit elements);
• grinder (cutting materials);
• pliers (bending a horizontal strip);
• a sledgehammer and a puncher, preferably with a special nozzle for rods (driving vertical electrodes).

Work progress (with photo)

Site selection and soil development

Dig trenches under the contour near the house. So, you do not have to dig a long trench to build

First of all, you need to choose a place where the ground loop will be located. To minimize the amount of work and the consumption of materials, the installation of a grounding device should be carried out near the house of the building.

After site selection, earthworks are carried out. We take a shovel and dig trenches. In our case, there will be three of them, that is, we make a contour according to the "equilateral triangle" scheme. The depth and width of the trench should be more than half a meter, and the length should correspond to the calculation. It is also necessary to dig a recess from the nearest vertex of the triangle to the force shield.

Assembling the ground loop

If the soil is not homogeneous, then use a hammer drill to drive in the pins.

1. First, we prepare vertical ground electrodes. We cut them with a grinder in accordance with the calculated data. Then we grind the ends of the pins under the cone. This is done so that the electrode enters the ground more easily.
2. Then we cut the steel strip. The length of each segment should be slightly longer than the side of the triangle (about 20–30 centimeters). It is advisable to bend the ends of the strips in advance with pliers for tight contact with the pins during welding.
3. We take the prepared pins and hammer them into the vertices of the triangle. If the ground is sandy and the electrodes go in easily, then you can get by with a sledgehammer. But if the soil density is high or stones often come across, then you will have to use a powerful hammer drill or even drill wells. We hammer the rods so that they protrude above the base of the trench by about 20-30 centimeters.
4. Next, we take a metal strip 40 × 5 millimeters and grab it by welding to the pins. As a result, you will get a contour in the form of an equilateral triangle.
5. Now we make a contour approach to the building. For this we also use the strip. It must be taken out and fixed against the wall (if possible, near the switchboard).

Weld the bolt to the bus well, since the resistance of the ground loop depends on the quality of the contact

Helpful Hint: Protect welding seams from corrosion. Paint the connection points of the contour elements and the bus outlet at the building with black exterior paint. The remaining parts of the grounding device must not be painted over!

All welded joints must be painted, as these places are most susceptible to destruction.

After installing the protective grounding circuit of the house, we fill the trenches with homogeneous soil without construction debris and rubble. It is recommended to use dense homogeneous fine-grained compositions for these purposes.

Video instruction for installation of the ground loop

Shield connection

To connect the circuit to the electrical panel, you need to use a copper wire with a cross section of 10 square millimeters. Screw one end of it to the ground electrode terminal, and lead the other end into the building and screw it to the power shield. By the way, if the switchboard is located in the house, then the same strip can be used to establish grounding, and the bolted transition can be done already indoors.

In a private house, the ground loop is connected according to the TN-C-S or TT scheme

Here it is also worth paying attention to the connection diagram of the circuit to the shield. In private homes, power is often provided by overhead lines (VL) over the TN-C grounding system. In this circuit, the source neutral and the protective conductor are combined. That is, a phase wire (L) and a combined "zero" and "ground" (PEN conductor) are suitable for the shield. Therefore, when connecting the circuit to the electrical installation, the TN-C system must be converted to TN-C-S, in which the PEN conductor is divided into zero working (N) and zero protective (PE) conductors. In this case, three wires will already come to the consumer: “phase”, separately “zero” and “ground”.

But how to connect a house to a grounding device using the TN-C-S system? This is done quite simply. To get a three-core electrical wiring with a separate protective conductor, you need to perform the following steps in the switchboard:

1. Install a metal bus in the shield (you can buy it at any electrical supply store). Then connect it with a copper wire to the RSH housing. This will be the PE ground bus.
2. We connect the combined PEN conductor coming from the power source to the PE bus.
3. Then we make a jumper between the ground bus and the zero working conductor N, the bus of which must be isolated from the switchboard.
4. At the end, we connect the phase wire to a separate bus, which is also not connected to the RSH case.

You can connect the building to the circuit in another way - using the TT system. In this case, you do not need to share anything. The phase wire is connected to an isolated bus, and the combined PEN conductor from the power source sits on a second separate bus and is considered "zero". Well, the shield body is connected to a grounding device. Thus, when connecting the circuit according to the TT scheme, it is not electrically connected to the PEN conductor. The only drawback of such a connection is the need to install additional protective devices, such as an RCD.

Earth resistance measurement

The measurement of the spreading resistance of the ground electrode is carried out by means of a verified instrument F4103-M1

After installing and connecting the circuit, it is imperative to check whether it will protect you from electric shock. To do this, it is necessary to measure the resistance of current spreading and metal bonding.

As noted earlier, in accordance with PUE 1.7.101, the resistance of the grounding device at any time of the year should not exceed 2, 4, 8 Ohms at line voltages of 660, 380, and 220 V of a three-phase current source or 380, 220 and 127 V of a single-phase current source . To measure the resistance of the circuit, you need a special device F4103-M1. It is expensive, so it makes no sense to buy it. It is much easier to invite employees from the energy department or electrical laboratory, who will take measurements and issue a passport and a protocol for the grounding device. If the resistance of the circuit exceeds the norm, then additional pins will have to be driven in.

Measuring the resistance of a metal bond allows you to determine the presence of a circuit between grounding and grounding elements. This parameter is measured with an F4104-M1 microohmmeter. In accordance with PTEEP clause 28.5, the contact resistance should not be more than 0.05 Ohm. If the resistance of the metal connection is above the norm, then all bolted and welded connections of the circuit elements will have to be checked.

As for the frequency of checking the condition of grounding devices, it is determined by the schedule of preventive maintenance. It is approved by the technical head of the consumer. In accordance with clause 2.7.9. PTEEP, visual inspection of the outer parts of the ground electrodes must be carried out at least once every six months. A survey with a selective opening of the earth - once every 12 years.

Important: The loop resistance must be below normal all year round, so it is advisable to check the ground electrode during drought or frost (when the soil resistivity increases).

The most common mistakes when doing work

Mistakes that should not be made when arranging a protective ground loop in a private house:

• If you decide to seek help from installers, then you need to make sure that they use only suitable materials. The fact is that many organizations are trying to save on electrodes and dig pins with low conductivity into the ground, for example, rusty fittings. And this, as you already know, greatly worsens the protective properties of the circuit or even makes it useless.
• Grounding device at a great distance from the building. The circuit does not pose a danger to humans, so it should be installed closer to home. And it is desirable that the ground electrode is located in the wettest place. After all, water improves conductivity, which leads to a faster circuit closure and instantaneous operation of protective equipment.
• Connection of the ground loop with lightning protection. If your switchboard does not have an SPD device that opens the circuit in the event of an overcharge, then a large current from the lightning rod can damage the electrical equipment or the switchboard itself.

The protective ground loop is a mandatory safety measure when using electrical appliances in a private house. If you decide to do the grounding yourself, then do all the work in accordance with the above rules and recommendations. At the same time, do not forget about safety precautions when working with welding and power plants.

Modern a private house equipped with a large number of household electrical appliances. To connect them to the power supply, it is necessary to carry out grounding for safety reasons. From this article you can learn how to properly make a ground loop in a private house with your own hands.

What is grounding?

This is the name of a specially made connection to the ground of electrical equipment elements. Its main purpose is guaranteed protection against the effects of electric current in the event of a household appliance failure.

Grounding kit

On sale you can find special grounding kits, the price of which is about 4,600 rubles. You can also purchase separate accessories for installation, they are inexpensive. For example, a steel rod (electrode) 1.5 m long will cost 500 rubles, a coupling - 200 rubles, a connecting bus - 850 rubles. Each grounding kit has a corresponding installation manual, which takes into account the specifics of all products.

However, most of the required elements can be made independently. In addition, the choice of materials is quite wide. You just need to know the requirements that apply to them.

Vertical earthing

• Corner 50x50x5 mm.
• A pipeline with a diameter of at least 32 mm, while the wall thickness must be 3.5 mm or more.

These electrodes can be used at power consumption volumes not exceeding 15 kW.

Horizontal earthing

• Steel wire with a cross section of at least 10 mm 2.
• Strip mm.

conductors

As conductors, you can use a metal strip, or a copper wire. For example, a SIP wire with conductors of the appropriate section and without insulation. When laying in a trench - at least 25 mm 2, with open laying - at least 16 mm 2.

Circuit Features

Marking and site selection

The installation of the ground loop should be carried out closer to the house, taking into account the distances indicated above. The length of the connecting "line" in this case will be minimal, which will reduce material consumption. And most importantly, in the future it will not interfere with the conduct of economic activities - the laying of engineering communications, the laying out of flower beds.

Calculation

To make an accurate calculation is beyond the power of a person who does not have deep knowledge. Since a complex form is used for the calculation, which contains many coefficients characterizing the properties of the soil, soil moisture, as well as the climatic conditions of the zone. These coefficients can only be obtained through complex additional analyzes and calculations, which requires a certain qualification and, accordingly, will be expensive.

For this reason, consider how to make a ground loop in a private house with your own hands more in a simple way. Taking into account the fact that household equipment operates in a certain range of circuit resistance, in which it will function normally.

Mounting

It is not so easy to make a ground loop in a private house with your own hands. This process is quite laborious and includes the following steps:

How to bring into the house?

The ground loop is connected to the metal strip that was used to connect the electrodes, as follows:

Checking the ground loop

For an accurate contour, special equipment is required. In its absence, you can use the popular method, which will allow you to determine the performance of the resulting circuit.

It is necessary to take a powerful consumer (from 2 kW) and connect it in this way: to the phase in the apartment - one end of the supply wire, to the ground - the other, and the device should work. Then you should measure the voltage in this network with the equipment turned off and on. A slight voltage difference (5-10V) indicates that you have made the correct ground loop, which is completely ready for use.

If the test showed a significant difference in voltage, then you will need to add more electrodes. From the top of the triangle, another trench 2.5 m long is dug in any direction, and at its end an additional corner is driven into the ground, which is connected to the strip, and the check is carried out again. If everything is fine, then the ground loop (diagram above) can be considered ready.

Forbidden

• Connect conductors to metal pipelines of any engineering communications.
• Coat the elements of the scheme with paintwork compositions.
• Use a "neutral" wire to connect the ground.
• Position horizontal earthing and connectors at the top (ground laying is used in rare cases).

1. Before starting work, it is recommended to draw up a temporary circuit diagram, which it is desirable to save. After all, over time, a lot is forgotten, and in order not to subsequently guess where the connector goes and where the electrodes are laid, there will always be a circuit diagram at hand.

2. Electrodes may be placed not only at the vertices of the triangle. They can be arranged in an arc, on a line. It is important that the total resistance of the grounding system does not exceed 3 ohms (voltage circuit up to 500 V) and 4 ohms (up to 1 kW). If necessary, this indicator is reduced by installing another 1-2 rods.

3. If it is not possible to make a measurement on your own, then for absolute confidence in the quality of the installation of the circuit, it is advisable to invite a specialist. This service will cost an average of 400-500 rubles.

Very often, this service is literally imposed on the power industry, convincing that only licensed organizations have the right to carry out this type of work. However, in none of the regulatory documents there is no indication of a ban on self-installation of the circuit.

Naturally, the installation can be ordered from power engineers, accept the finished work and pay for it. But if you are confident in your own abilities, why not mount the ground loop yourself.