Where to get grounding in a private house. Overview of poe norms for the ground loop. What to make a metal bond

The ground loop of the house, let's try to mount it yourself. Previously, an article has already been written, what is and why we need it.

I will not consider the installation of a ground loop in an apartment of a multi-storey building, for the simple reason that in high-rise buildings, either there is a PE protective conductor (the third wire is in your apartment) or it is not. And trying to make protective grounding in the apartment on your own (connecting the wire to the heating pipes, to the electrical panel on the floor) is the height of stupidity and carelessness!

The ground loop of the house is a metal structure consisting of horizontal and vertical electrodes (ground electrodes) - steel corners, strips, pipes.

The ground electrodes of the grounding circuit of the house, on average 2-3 meters long, are driven into the ground with a sledgehammer and connected to each other with a steel strip by welding. As a rule, the upper layers of the soil have more resistance than the lower ones, so the electrodes must be driven into the ground, as deep as possible, but without fanaticism. According to the PUE, the ground electrodes of the ground loop of the house must be either copper or steel.

There are also ready-made modular-pin grounding systems for a private house on sale, but their cost and installation will, of course, be an order of magnitude higher than you do on your own.

Chernozem, clay, loam, peat are most suitable for installing a ground loop at home. Stone and rocky soil are not suitable for mounting the ground loop. Here I think it is clear that the higher the resistivity of the soil, which rocky and rocky ones have, the greater the resistance value will be of the ground loop itself.

The ground loop of the house is located at a distance of no closer than 1 meter from the dwelling, but no further than 10 meters. It is best to place the ground loop of the house in a place that will most often be in the shade.

The most common ground loop of a house is in the form of an equilateral triangle, into the tops of which electrodes are driven in, interconnected by a steel strip. It is necessary to know that the closer the electrodes of the ground loop of the house are located to each other, the less its efficiency. You can place the electrodes in one line, but in this case you need 4-5 electrodes, the distance between which will be 1 meter. The smallest dimensions of grounding electrodes (ground electrodes) are indicated in the PUE.

To build a ground loop at home, we need to dig a trench in the form of an equilateral triangle with sides of about 3 meters, a depth of 0.6-0.7 m and a width of 0.4-0.5 meters with a shovel.

We hammer electrodes (steel corners 40x40x5) about 3 meters long along the vertices of the triangle of the grounding loop of the house, but we do not hammer it to the end, leaving 0.15-0.25 m above the ground.

To make it easier to clog the electrodes, it is better to sharpen them in advance, for example, with a grinder.

You can drill small wells under the ground electrodes of the ground loop of the house.

We do not forget the places of welding of the ground loop of the house, treat it with a special anti-corrosion coating, but in no case, not paint, which is a dielectric and does not conduct current. Also, do not connect the plates with the corners using bolted connections, over time the connection weakens, rusts, and the ground loop of the house loses its effectiveness.

Then, from the nearest vertex of the triangle of the ground loop to the house, we lay a steel plate to the main ground bus (GZSH) of our. You can connect the ground loop of the house with the GZSH of the electrical panel in a different way, we bring out a steel strip above the ground, for example, at the blind area of ​​​​the house, weld a bolt to it and connect a copper bus, or a copper flexible wire, with a cross section of at least 10 sq. mm.

After completing the installation of the ground loop at home, it is necessary to check the correctness and quality of the installation. To do this, it is necessary to conduct a visual inspection of the ground loop, check the bolted connections, the quality of the welds for cracks, and measure the resistance of the ground loop.

The resistance of the ground loop is measured with special instruments, and according to the PUE, clause 7.1.101, it should be no more than 30 Ohm, both for a three-phase electrical network with a voltage of 380 V, and for a single-phase voltage of 220 V, and the lower the resistance of the ground loop, the better for us . They measure the resistance of the ground loop of the house in dry weather in summer, and maximum freezing of the soil in winter, i.e. when the resistance of the soil itself is maximum.

Many sites on electrical topics, including top ones, as well as energy supervision inspectors, either out of ignorance, or for some selfish purposes, mislead people, citing the ground loop resistance value of 4 Ohms. This is incorrect and if you carefully read the requirements of the PUE, it applies to transformers and generators, the neutrals of which are directly connected to the ground loop. And the resistance of the ground loop of a private house will be, as I mentioned above, no more than 30 ohms.

As a rule, you can order the measurement of resistance and installation of the ground loop of a private house from the network organization that issued you the technical conditions for connecting to electrical networks.

If you orderedprivate house, then all the necessary calculations, the name and parameters of materials for the ground loop of the house will be indicated in the project.

I am not a professional builder or electrician, so when building my frame house, I always start by studying the theory and guiding documents (SNiP, PUE, etc.). When connecting 380 V, when the question of grounding arose, I again turned to theory.

General provisions of the grounding system in a private house (3 phases, 380 V)

According to the PUE (ed. 7), electrical installations with voltage up to 1 kV in relation to electrical safety measures are divided into:

1. electrical installations in networks with dead-earthed neutral;
2. electrical installations in networks with isolated neutral.

open conductive part - accessible to touch conductive part of the electrical installation, normally not energized, but which may become energized if the basic insulation is damaged.

For electrical installations with voltage up to 1 kV, the following designations are accepted:

• - system TN, in which the functions of zero protective PE and zero working N conductors are combined in one conductor in some part of it, starting from the power source (it can be obtained by making some changes to TN-C);
• TT - a system in which the neutral of the power supply is solidly grounded, and the exposed conductive parts of the electrical installation are grounded using a grounding device that is electrically independent of the solidly grounded neutral of the source (i.e. zero N and ground PE are isolated from each other).

Designation of other systems

1. TN- a system in which the neutral of the power source is solidly grounded, and the open conductive parts of the electrical installation are connected to the solidly grounded neutral of the source by means of zero protective conductors;
2. TN-C - system TN, in which the zero protective and zero working conductors are combined in one conductor throughout its entire length (the most common in Russia);
3. TN-S- system TN, in which the zero protective and zero working conductors are separated along its entire length;
4. IT- a system in which the neutral of the power supply is isolated from earth or earthed through high resistance appliances or devices, and the exposed conductive parts of the electrical installation are earthed.

System drawings TN-C, TN-S, TN-C-S

Deciphering letters

Deciphering letters:

1. Subsequent (after N) letters - combination in one conductor or separation of the functions of the zero working and zero protective conductors:
   • S- zero worker (N) and zero protective (RE) conductors are separated;
   • WITH - the functions of the zero protective and zero working conductors are combined in one conductor ( PEN-conductor);
2. The second letter is the state of open conductive parts relative to ground:
   • T - exposed conductive parts are grounded, regardless of the relation to the earth of the neutral of the power supply or any point of the supply network;
   • N- exposed conductive parts are connected to a dead-earthed neutral of the power source.
3. The first letter is the state of the neutral of the power supply relative to earth:
   • T - grounded neutral;
   • I - isolated neutral.
4. N- zero working (neutral) conductor;
5. RE - protective conductor (grounding conductor, zero protective conductor, protective conductor of the potential equalization system);
6. PEN- combined zero protective and zero working conductors.

Choosing a grounding system for a private house

For the modern private sector, only two earthing systems TT and TN-C-S are suitable. Almost the entire private sector is powered by transformer substations with a solidly grounded neutral and a four-wire power transmission line (three phases and PEN, a combined working and protective zero, or, in other words, a combined zero and earth).

Features of the TN-C-S earthing system

According to clause 1.7.61 of the Electrical Installation Code, when using the TN system, it is recommended to re-ground the PE and PEN conductors at the input to the electrical installations of buildings, as well as in other accessible places. Those. conductor PEN at the entrance to the house is re-grounded and is divided into PE and N. After that, 5 or 3 wire wiring is used.

Switching PEN and PE is strictly prohibited (PUE 7.1.21. In all cases, it is forbidden to have switching contact and non-contact elements in the circuits of PE and PEN conductors). The separation point must be upstream of the switching device. It is forbidden to break PE and PEN conductors.

Disadvantage of the TN-C-S system

• if the PEN conductor breaks, dangerous voltage may be present on the cases of grounded electrical appliances.

Description of the TN-C-S system - Description of the TN-C-S system

The TN-C-S grounding system is recommended to be made only on modern power lines made with SIP wire at which a break in only one wire is unlikely. Clause 1.7.61 of the PUE establishes that when using the TN system it is recommended to re-ground the PE and PEN conductors at the input to the electrical installations of buildings, as well as in other accessible places. Besides, re-grounding on power lines must be performed. For re-grounding, natural grounding should be used first. The resistance of the re-grounding earth electrode is not standardized. P. 1.7.103 of the PUE establishes that the total spreading resistance of ground electrodes (including natural ones) of all re-groundings of the PEN conductor of each overhead line at any time of the year should be no more than 5, 10 and 20 ohms, respectively, at line voltages of 660, 380 and 220 V three-phase current source or 380, 220 and 127 V single-phase current source. In this case, the spreading resistance of the grounding conductor of each of the repeated groundings should be no more than 15, 30 and 60 ohms, respectively, at the same voltages. These conditions reduce to zero the possibility of a dangerous potential appearing on the housings of electrical appliances.

According to clause 1.7.135 of the PUE, when the zero working and zero protective conductors are separated starting from any point in the electrical installation, it is not allowed to combine them beyond this point in the course of energy distribution. At the place of division PEN- conductor on the zero protective and zero working conductors, it is necessary to provide separate clamps or busbars for conductors interconnected. PEN- the power line conductor must be connected to the clamp or busbar of zero protective RE-conductor.

To ensure a high level of safety against electric shock in the TN-C-S system, it is necessary to use residual current devices (RCDs).

Features of the TT earthing system

Description of the TT system - Description of the TT system

The TT system differs from TN-C-S only in the absence of a connection between the PEN conductor and the grounding of the house, i.e. the protective conductor PE is grounded independently of the neutral conductor N and any connection between them is prohibited. Therefore, in schemes, PEN is usually denoted as N, since we do not receive PE from PEN.

Comment

According to clause 1.7.54 of the PUE, artificial and natural ground electrodes can be used for grounding electrical installations. If, when using natural grounding conductors, the resistance of the grounding devices or the contact voltage has an acceptable value, and the normalized values ​​​​of the voltage on the grounding device and the permissible current densities in natural grounding conductors are provided, the implementation of artificial grounding conductors in electrical installations up to 1 kV is not necessary.

The use of natural grounding conductors as elements of grounding devices should not lead to their damage when short-circuit currents flow through them or to disruption of the operation of the devices with which they are connected.

The following can be used as natural grounding conductors (clause 1.7.109 of the PUE):

1. metal and reinforced concrete structures of buildings and structures in contact with the ground, including reinforced concrete foundations of buildings and structures with protective waterproofing coatings in non-aggressive, slightly aggressive and medium-aggressive environments;
2. metal water pipes laid in the ground;
3. casing pipes of boreholes;
4. metal sheet piles of hydraulic structures, conduits, embedded parts of gates, etc.;
5. rail tracks of the main non-electrified railways and access roads in the presence of a deliberate arrangement of jumpers between the rails;
6. other metal structures and structures located in the ground;
7. metal sheaths of armored cables laid in the ground. Cable sheaths can serve as the only grounding conductors when the number of cables is at least two. Aluminum cable sheaths are not allowed to be used as grounding conductors..

It is not allowed to use as grounding conductors:

• pipelines of flammable liquids, flammable or explosive gases and mixtures;
• sewerage and central heating pipelines.

These restrictions do not exclude the need to connect such pipelines to a grounding device in order to equalize potentials in accordance with 1.7.82.

Artificial grounding conductors can be made of black or galvanized steel or copper, and must not be colored.

The method of mounting vertical grounding depends on the following factors:

1. dimensions of ground electrodes;
2. the nature of the soil, its moisture and condition during installation;
3. season and climatic conditions (thawed, frozen);
4. the number of immersed electrodes;
5. remoteness of objects from each other, as well as the availability and possibility of using the mechanisms and devices necessary for installation.

The smallest dimensions of grounding conductors and grounding conductors laid in the ground

* Diameter of each wire.

Laying aluminum bare conductors in the ground is not allowed.

Rational ways to install ground electrodes in a private house:

• for thawed, soft soils - indentation and screwing in of rod electrodes, driving in and indentation of profile electrodes;
• for dense soils - driving electrodes of any section;
• for frozen soils - vibration immersion;
• for rocky and frozen soils, if deep immersion is necessary - laying in a drilled well.

The denser the soil adjoins the conductor, the lower the resistance (i.e., the minimum resistance to spreading at a clogged electrode, and the maximum - at an electrode laid in a finished well and covered with loose soil).

More

The resistance of the electrodes increases slightly when pressed into the ground and when immersed by vibrators and exceeds the resistance of clogged electrodes by only 5-10%.

After 10-20 days, the resistance of the electrodes immersed in vibrators, pressed in and clogged, begins to level off. Significantly more time is required to restore the soil structure and reduce the resistance of electrodes screwed into the soil, especially when using an extended tip on the electrode, which facilitates immersion, but loosens the soil.

The place for wiring the ground loop is preferably located near the grounded electrical installation (power panel). You will need a corrosion-resistant steel angle (50 x 50 x 5 mm) or a rod and a corrosion-resistant steel strip (4 x 40 mm) to connect the actual ground electrodes and the ground loop and power shield. Most often, an equilateral triangle (3 x 3 x 3 meters) is dug out, along the tops of which 3 ground electrodes are clogged (in order for the corner to be freely driven into the ground, its ends must be sharpened with a grinder). To three ground electrodes (corners) installed in the ground, a corrosion-resistant steel strip is welded around the perimeter. Next, a trench is dug (width 0.5 meters and depth 0.8 meters) to the house. We lay a steel strip in the trench. We weld one end of the strip to the ground loop, and connect the other to the PE bus in the ASU. We bury the trenches with a homogeneous soil that does not contain crushed stone and construction debris. All ground loop connections are made by welding.

The length of the vertical electrodes is determined by the project, but should not be less than 1 m; the upper end of the vertical grounding conductors should be buried, as a rule, by 0.5-0.7 m.

Horizontal grounding conductors are used to connect vertical grounding conductors or as independent grounding conductors. The depth of laying horizontal ground electrodes is at least 0.5-0.7 m. A smaller laying depth is allowed at the points of their connection to equipment, when entering buildings, at intersections with underground structures and in areas of permafrost and rocky soils.

Horizontal ground electrodes made of strip steel should be laid on the edge of the trench bottom.

The trenches for horizontal ground electrode systems must first be filled with homogeneous soil that does not contain crushed stone and construction debris, compacted to a depth of 200 mm, and then with local soil.

When driving vertical ground electrodes, steel electrodes of any profile can be used - angled, square, round, however, the lowest metal consumption (with the same conductivity) and the highest resistance to ground corrosion (in the case of equal metal consumption) are achieved when using rod electrodes made of round steel.

When driving into ordinary soils to a depth of up to 6 m, it is economical to use rod electrodes with a diameter of 12-14 mm. At a depth of up to 10 m, as well as when driving short electrodes into particularly dense soils, stronger electrodes with a diameter of 16 to 20 mm are required.

Horizontal earthing switches can be made of round, strip or any other steel. Preference should be given to round steel, which, with the same mass and conductivity, has a smaller surface and greater thickness, as a result of which it has less corrosion vulnerability (it is recommended to use low-carbon round steel).

If there are reservoirs near the objects, extended grounding conductors are laid at the bottom of the reservoirs, and connecting cable or overhead lines to the objects are laid from them.

Cross-sections of grounding conductors in electrical installations with voltage up to 1 kV:

The grounding conductor connecting the working (functional) grounding conductor to the main grounding bus in electrical installations with voltage up to 1 kV must have a cross section of at least:

• copper - 10 mm 2,
• aluminum - 16 mm 2,
• steel - 75 mm 2.

Main ground bus

According to clause 1.7.121 of the PUE, the following can be used as PE conductors in electrical installations with voltages up to 1 kV:

1. dedicated conductors:
   • conductors of multicore cables;
   • insulated or uninsulated wires in a common sheath with phase wires;
   • permanently laid insulated or bare conductors;
2. exposed conductive parts of electrical installations:
   • aluminum cable sheaths;
   • steel pipes for electrical wiring;
   • metal shells and supporting structures of bus ducts and prefabricated complete devices (provided that the design of boxes and trays provides for such use, as indicated in the manufacturer's documentation, and their location excludes the possibility of mechanical damage);
3. some third party conductive parts:
   • metal building structures of buildings and structures (trusses, columns, etc.);
   • reinforcement of reinforced concrete building structures of buildings, subject to the requirements of 1.7.122;
   • metal structures for industrial purposes (crane rails, galleries, platforms, elevator shafts, elevators, elevators, channel framing, etc.).

P. 1.7.122. The use of exposed and third-party conductive parts as PE conductors is allowed if they meet the requirements of this chapter. to the conductivity and continuity of the electrical circuit.

Zero protective conductors of circuits are not allowed to be used as zero protective conductors of electrical equipment powered by other circuits, as well as to use open conductive parts of electrical equipment as zero protective conductors for other electrical equipment, with the exception of shells and supporting structures of busbars and complete factory-made devices that provide the ability to connecting protective conductors to them in the right place.

The use of specially provided protective conductors for other purposes is not permitted.

The main ground bus can be made inside the input device of the electrical installation with a voltage of up to 1 kV or separately from it (clause 1.7.119. PUE).

Inside the input device, the PE bus should be used as the main ground bus.

When installed separately, the main ground bus must be located in an accessible, convenient place for maintenance near the input device.

The cross section of a separately installed main ground bus must be at least the cross section of the PE (PEN) conductor of the supply line.

The main ground bus should usually be copper. It is allowed to use the main earthing bar made of steel. The use of aluminum tires is not allowed.

The busbar design shall provide for the possibility of individual disconnection of the conductors attached to it. Disconnection must only be possible with the use of a tool.

External conductive parts may be used to connect several main earth busbars if they comply with the requirements of 1.7.122 for the continuity and conductivity of the electrical circuit.

Connections and connections of grounding, protective conductors and conductors of the potential equalization and equalization system

Connections and connections of grounding, protective conductors and conductors of the potential equalization and equalization system must be reliable and ensure continuity electric circuit (i.e. it is not allowed to break the indicated circuits with fuses, circuit breakers, etc., clause 1.7.139).

Connections of steel conductors are recommended to be made by welding. It is allowed indoors and in outdoor installations without aggressive environments to connect grounding and neutral protective conductors in other ways that ensure the requirements of GOST 10434 “Electrical contact connections. General technical requirements” for the 2nd class of connections.

Connections must be protected from corrosion and mechanical damage. For bolted connections, measures must be taken to prevent contact loosening.

Connections of protective conductors of electrical wiring and overhead lines should be carried out by the same methods as the connections of phase conductors.

When using natural grounding conductors for grounding electrical installations and third-party conductive parts as protective conductors and potential equalization conductors, contact connections should be made using the methods provided for by GOST 12.1.030 “SSBT. Electrical safety. Protective grounding, zeroing.

The connection of each open conductive part of the electrical installation to the neutral protective or protective earth conductor must be carried out using a separate branch. Sequential connection of open conductive parts into the protective conductor is not allowed. (clause 1.7.144. PUE).

According to clause 1.7.145, it is not allowed to turn on switching devices in the circuits of PE and PEN conductors, with the exception of cases of power supply to electrical receivers using plug connectors.

If the body of the socket outlet is made of metal, it must be connected to the protective contact of this socket.

The need for grounding in a private house is undeniable. Protecting relatives and friends from the possible receipt of various electrical injuries is a guarantee of safe living in your home. But what if a private house has already been built and there is no grounding in it?

Then you have to do it yourself or hire electricians to do all the work. But in fact, there is nothing complicated in its device; any owner who knows how to handle a grinder and a welding machine is able to perform work on creating a ground loop. Therefore, we will analyze the issue in detail, point by point.

During the operation of electrical appliances, they are influenced by many different factors:

1. vibration at work.
2. Moisture condensation out of the air
3. Temperature changes and much more.

Accordingly, over time, the likelihood increases that the insulation of wires or other current conductors will be broken and a short circuit will occur on the device case. This is a dangerous situation and the consequences can be very different.

Consider 4 main options:

1. Grounding is not done, there is no circuit breaker. This is the most dangerous situation, in this case, you can find out about the breakdown of the current to the case when a person receives an electrical injury. The degree of damage to the body depends on many factors and can lead to death.
2. Grounding is done, there is no circuit breaker. Since the fuse is triggered when the current leakage exceeds certain limits, it is not always that during a breakdown of the current to the body of the electrical appliance, the power is turned off. Therefore, an electric shock with a voltage of up to 100 volts is possible. This can cause serious damage, and is deadly for people with pacemakers.
3. There is no grounding, the circuit breaker is installed. In this case, the machine will not work if there is a breakdown of the current to the case. The power will turn off only when a person touches the case, and will have contact with another conductor. That is, the human body closes the circuit and current leakage occurs. In this case, the RCD will trip within 0.1 - 0.3 sec. and turn off the power. The blow will be weak, but unpleasant.
4. Grounding has been made and a circuit breaker has been installed. Only then is complete security guaranteed. In the event of a current breakdown to the case, current will leak through the ground. Within 0.1 - 0.3 sec. RCD trips and turns off the power. If the leak is too large, then the fuse may also work, reliably protecting people from.

Only the installation of all protection systems will make it possible to protect the people living in the house, so do not neglect safety precautions.

Necessary materials and tools

For installation you will need:

1. metal pins(fittings, pipes, profile or corners) in an amount sufficient to create electrodes.
2. metal strip 50 - 100 mm wide, at least 3 mm thick. The length of the strip is determined by the length of the ground loop and is calculated in advance.
3. Stainless steel strip. The width is also 50 - 100 mm. It is used as a current-carrying element, so its length should be enough for laying from the wall of the house to the contour.
4. Welding machine. Only a welded joint will ensure sufficient electrical conductivity between the elements. It is worth noting that for cooking stainless steel it is necessary to use specialized electrodes, which must be stocked up in advance.
5. Bulgarian. The metal will need to be cut and the electrodes sharpened to facilitate the process of clogging them.
6. Sledgehammer. The easiest way is to dig a hole half a meter deep - a meter and hammer the pins to the desired length than bury them or drill wells.
7. Bolt M8-M10. A bolt is installed at the end of the stainless steel strip to connect the wire leading out of the building.
8. Copper wire with a cross section of at least 6 mm 2. It is bolted to the current-carrying plate and brought out to the switchboard for connection to a common ground loop.

Step-by-step instructions for installation in a private house

The installation process of the structure consists of the following steps:

1. At the chosen location we dig a hole or a trench for electrodes and a trench to the house for a current-carrying strip. The depth should be such that the top cut of the pins is 20-30 centimeters above the bottom. This will make welding easier. If you are digging a trench, then take into account its width. If it is too narrow, it will be inconvenient to work and it is better to spend an extra hour on earthworks than to drive in electrodes and install strips twice as long.
2. Future electrodes are driven into the ground. To facilitate this action, it makes sense to lubricate the metal and periodically pour water into the place of driving. There will be some dirt, but the process will go easier.
3. Circuit installation. Metal strips are welded to the electrodes, then the welding points are covered with an anti-corrosion coating. This cannot be neglected, since the metal will be in the ground and actively corrode. And the integrity of the circuit is a guarantee of the operation of the circuit.
4. Installation of a current-carrying conductor. A strip of stainless steel is laid on the bottom of the trench, welded to the ground loop at one end, and led out near the wall above ground level with the other. The output must be vertical so that there is a minimum level of dissipation of the transferred charge on the soil surface.
5. Digging holes. All installation is done, and the pits can be filled up.
6. On the withdrawn part of the current-carrying strip with the help of a bolt, a copper wire is attached, which is then output to the switchboard of the building.

Examination

When the installation of grounding is completed, it is necessary to check it. This requires a special device. Due to its specificity and high cost, it is not common in a professional environment, so it is difficult to find it.

There is a way to check using a voltmeter and an ohmmeter, but the process of performing it and processing the results requires special knowledge of electricity. Therefore, it is not suitable for most people.

But do not give up and hope that everything is done correctly.

There is an easy way to check if grounding is working:

1. For this, a socket is installed, in which the phase is connected as usual, and instead of zero, a wire is connected leading to ground.
2. Then an ordinary table lamp with incandescent lamp. The brighter the lamp burns, the better the circuit works.
3. Respectively if an RCD is installed, then there will be a bright flash, and then the automation will work.
4. After verification it is necessary to return the socket to its normal state, otherwise the automation will turn off every time it is used.

Operating principle

Purpose of grounding installation- this is to divert electrical current away from people, in the event of a power failure to the case. Therefore, together with a residual current device (RCD), it plays the role of a malfunction indicator.

If a current breakdown occurs, a large leakage immediately occurs due to grounding, because of this, the RCD turns off the power. And it becomes clear to the owner that something is wrong with the electrical appliances in the house and it is necessary to take action.

Let's consider the whole situation step by step:

1. For some reason a power failure has occurred. It does not matter whether it is spilled water, electrical wiring that has peeled off from time to time, or some other reason, a breakdown has occurred.
2. Since the case is grounded, the current begins to flow through the ground wire to the electrodes dug in the street.
3. Thanks to the large area electrodes, the voltage drops and dissipates in the surrounding soil.
4. Protection device trips due to a large current loss and turns off the power to the circuit. The leakage current stops.

These 4 stages take place in 0.1 - 0.3 seconds, so a person may not even have time to notice what happened when the automation protects him from electrical injury.

Device in a private house

The ground loop is very simple. These are several pins dug in or driven in to a sufficient depth and interconnected by strips of iron 5-10 cm wide. A strip of stainless steel departs from them to the house, and already a ground connection is made to it.

The location of the electrodes does not play a big role, but the most common are the following schemes:

1. Row. The pins are deepened in one line, a current-carrying strip is welded to the last one. The disadvantage is the absence of a second circuit, if the connection of the strips and electrodes is broken, then only the pin to which the current-carrying strip is attached will work.
2. Triangular. The most popular scheme, due to its simplicity. The pins are arranged in the form of an equilateral triangle, connected with iron strips, and a current-carrying strip is welded to one of the corners. The presence of a closed loop guarantees the operation of the ground, even if one strip is damaged or poorly welded.
3. Rectangular. It is similar to triangular, but the contour is cooked in the form of a square or rectangle.
4. Circular. An option when the pins deepen in a circle or oval. The benefits are the same as the previous two, but more difficult to perform.

Calculation

The process of accurately sizing the ground loop and the number of electrodes needed is very complex and takes many factors into account.

However, for a private house, high accuracy and the use of complex formulas are not necessary, only an approximate calculation is enough, which will cover possible current leaks with a margin.

The number of electrodes primarily depends on the soil and the level of underlying groundwater:

1. If the soil is sandy or sandy, contains stones and gravel, then it has a high resistance.
2. clay soil and various loams are better suited.
3. The lowest resistance have ash and saline soils.

Therefore, in the first case, 7-10 electrodes are required, in the second, 5-7, and in the third, 3-5 pieces are enough. The high level of groundwater makes it possible to get by with a minimum number of electrodes, but if the soil is dry and far from water, then it is worth increasing their number.

The length of the electrode also matters. The NEC safety standard requires the lower end of the pin to be at least 2.4 meters below ground level. To achieve full grounding, it would be better if it reaches the mark of 3 m.

The top edge should be at least 0.5 meters from the surface. The length of the pin is calculated depending on your wishes and possibilities. The section should not be less than 1.5 cm if it is a rod or reinforcement, if it is a corner or a profile, then the minimum size is 30 by 30 mm.

Rules and requirements for grounding

1. It is important to properly position the electrodes in the ground. The distance between them should not be less than a meter, 1.8 - 2 m is considered ideal. Then even high voltage will dissipate in the soil without problems, the operation of the electrodes will be independent.
2. Also, it is worth choosing the right place for burying the contour. In the event of its operation, a charge of electric current will be dissipated around it. Therefore, it is important to choose a place so that there are no people within a radius of 1-2 m from it. It can be a place in the middle of a flower bed or under an alpine hill, which is rarely approached by anyone, preferring to admire from a certain distance. The current strength will be small and it is impossible to get a serious electrical injury, but health is not an area that you can joke with.

Errors and cost

1. The most common mistake is the small distance between the electrodes. In no case should it be allowed to be less than 1.5 meters. This is due to the fact that the current decreases with distance from the electrode if there is no charge in the soil. If the fields from 2 electrodes intersect, then the dissipation process will deteriorate significantly and the time after which the RCD will de-energize the network will increase.
2. The second most common mistake is the savings on electrodes. They are made 3 or 6, regardless of the type of soil and the level of water occurrence. Somewhere this is enough, but somewhere it may not be enough. As in the previous case, the rate of dissipation of the charge decreases and the increase in the operation of automation.
3. 3rd most popular, but not in importance, the mistake is that they do not install an RCD. Hoping that grounding saves, protective automation is not mounted. This approach can lead to gigantic current leakage, heating of the wires and, as a result, a fire. Only in combination they can provide full protection, and installation of one without the other is unacceptable.

The main expenses for do-it-yourself grounding installation are metal. The purchase of reinforcement and metal strips, depending on the size of the circuit and the region, costs from 3 to 10 thousand rubles. A stainless steel sheet is bought separately, cut into short strips and welded into one. Its price ranges from 2 to 4 thousand rubles, depending on the thickness.

Accordingly, the minimum cost of creating a ground loop is about five thousand, the maximum can be ten or even more.

Despite the apparent complexity, the process of making grounding is simple. Having analyzed all the stages in detail, and having considered all the main points, you can make sure that anyone can do it. A sufficiently skillful owner will cope without involving outsiders and hired workers.

More recently, the most powerful electrical appliances in the house were an iron, a stove and a boiler. Nowadays, the list of electricity consumers is regularly updated with equipment that makes life more convenient and comfortable. The flip side of the coin is that an increase in the number of household electrical appliances increases the risk of electric shock. To protect against the dangerous effects of high voltage, the housing of the electrical appliance is connected to the ground loop. In apartment buildings, wiring is laid taking into account the connection to the "ground", and in a private courtyard you can build reliable grounding with your own hands.

What is grounding: a little theory

Before proceeding with the construction of grounding, let's figure out what it is and how it works. Standard voltage is supplied to household consumers in two ways - through two or four wires. In the first case, there is a voltage of 220 V between the so-called phase and neutral conductors - such a network is called single-phase. In the second case, we are dealing with a three-phase network, in which electricity is transmitted by three phases and one zero. The potential between adjacent phases is 380 V, while the voltage between the neutral conductor and each phase is 220 V.

The scheme for connecting a house to a 220 V network with a ground loop is called single-phase

The neutral wire is often called "ground" and it is no coincidence. The fact is that it has a direct connection with the surface of our planet, as a result of which the potential between them is zero. If for any reason the connection to the neutral wire disappears, then a person can become a conductor of electricity. Getting under the reference voltage is deadly, so scientists have come up with a way to put the current on a different path. To do this, the case of modern electrical appliances is connected to a device that has good contact with the ground. According to the norms, its resistance should not exceed 4 ohms, while our body has a resistance of 100,000–500,000 ohms. Naturally, in this case, the current will flow along the path of minimum resistance and the person will be safe.

To connect the cottage to a three-phase network, four wires are used

The device mentioned above is called a protective earth loop. Thanks to him it is possible:

• reduce the risk of electric shock;
• avoid damage to household appliances when zero breaks;
• reduce the level of electromagnetic interference emanating from household electrical equipment and wiring;
• smooth out noise interference present in electrical networks.

Ground loops are not arranged arbitrarily, but in strict accordance with the following regulatory documents:

1. Safety regulations for the operation of electrical installations (PTBE).
2. Rules for the device of electrical installations of consumers (PUE).
3. Rules for the technical operation of consumer electrical installations (PTEE).

After reading all three documents, you will not find any mention anywhere that only qualified representatives of energy supply organizations are allowed to install ground loops. Accordingly, work to ensure electrical safety can be done independently. The main thing is that the ground loop is built in accordance with all the rules and complies with accepted standards.

Determining the type of protective device

The operation of electrical equipment requires the use of several types of grounding devices, the purpose of which is not only to protect people from high voltage, but also to ensure the normal functioning of the electrical appliances themselves. Therefore, today in production and in private households, two different connection schemes are used - the so-called protective and working grounding. Connections according to one scheme or another differ fundamentally and are never shared.

Protective earth

Protective ground loops are created for one purpose - to protect people from the damaging effects of current if the casing or other accessible parts of the equipment become energized for any reason. The connection to the ground is made with a small resistance (from 4 to 10 ohms), as a result of which the current passing through the human body is significantly reduced.

Protective grounding allows you to significantly reduce the current when you touch the device, the case of which is energized

This type of protective connection is made for the following mains and connections:

• two-wire DC networks built according to the scheme with an insulated common point of the coils of the supply voltage sources;
• household single-phase networks insulated from the ground with voltage up to 1 kV;
• three-phase AC networks with voltage up to 1 kV with insulated neutral wire;
• electrical networks of both types with voltages above 1 kV - with any zero mode.

In household electrical appliances, protective earthing is provided by a third contact, which is located on the power supply plug and is attached to the outer frame or casing of the equipment. The counterpart of the system is a separate contact in the socket, which, using grounding conductors, is connected to grounding conductors - metal elements dug into the ground.

Working ground

Grounding with a working circuit implies the connection to the ground of various current-carrying components of electrical installations, in particular, the neutral points of transformer coils or generator windings. It differs from the protective devices discussed above by its purpose - to ensure the normal functioning of the equipment in the event of an insulation breakdown, short circuit of one of the conductors to the ground, or to be able to quickly turn off the problematic part of the installation.

A working protective circuit with a dead-earthed neutral makes it possible to quickly turn off the faulty part of the installation

According to the standards, the resistance of the working ground loop should not exceed 4 ohms. Such a condition is due to the potential that can occur on the neutral wire relative to the ground at the time when the fault current begins to flow towards the ground electrodes.

For safety reasons, it is forbidden to combine the working and protective ground loops, since in this case current interference from atmospheric discharges can penetrate the network. This is fraught with disruption of the normal operation of electrical installations, up to equipment failure. In addition, the effectiveness of protective grounding is reduced, which in emergency situations will take over the functions of a worker or will be completely inactive.

Grounding networks 220 V and 380 V is practically the same in terms of the arrangement of the protective circuit. There are differences only in the connection method - in a 220 V network, switching is carried out using three wires (phase, neutral and earth), while 380 V connections require five wires (three phases, zero and earth).

Varieties of ground electrodes

It has already been repeatedly noted above that ground electrodes are used to drain the current - metal electrodes that are in direct electrical contact with the ground.

Distinguish grounding of natural and artificial type. As the first allowed use:

• metal parts of buildings, subject to low resistance at the points of their contact with the ground;
• casing pipes;
• underground parts of engineering communications built of metal;
• steel sheet piles of hydraulic structures;
• armored casings for underground cables.

It is not allowed to use in the form of natural grounding:

• engineering lines used for pumping flammable materials;
• pipelines that have anti-corrosion insulation;
• central heating pipelines;
• sewer pipes.

If it is not possible to connect to one of the natural protective structures, then you will have to resort to the help of artificial ground electrodes. Unlike natural structures, they are installed on purpose. To do this, they drive into the ground or lay at a certain depth:

• structural steel pipes with a diameter of 25–62 mm and a length of 2–3 m;
• steel corners with shelves of at least 50x50 mm;
• metal rods with a diameter of 10–12 mm;
• strip or tire steel, provided that its cross section exceeds 1.5 cm 2.

The surface of the electrodes should be as smooth as possible - this is necessary in order to achieve maximum contact with the ground. It is impossible to completely protect grounding from the harmful effects of corrosion. Destruction can be partially prevented in two ways - using a protective coating with anti-corrosion conductive compounds or choosing copper-plated or galvanized steel as electrodes.

Choosing a grounding scheme for a private house

Today, there are two protection schemes against the damaging effect of current - the connection of TN-C-S and TT. The peculiarity of the first is that in the neutral wire the protective zero is combined with the working one, while the second has a solidly grounded neutral. The supply of electricity to a private house most often occurs using overhead lines with a TN-C grounding scheme, which are characterized by the presence of a phase conductor (L) and a PEN protective conductor aligned with zero. To connect your own earth circuit, two methods are used:

• conversion of the traditional scheme to TN-C-S;
• ground connection via TT system.

Looking ahead, we note that the TT connection has become more widespread, since it implies the grounding of all current-carrying parts of the equipment. However, consider both of these methods.

TN-C-S connection

It has already been repeatedly said above that a separate protective wire is not provided in the TN-C system. To get a connection point to ground, the combined PEN conductor is divided into two separate lines - protective (PE) and zero working (N).

When connecting TN-C-S, the PEN wire is divided into two separate lines

For this purpose, an insulated N busbar is mounted in the electrical panel, in addition, a PE busbar is installed connected to the cabinet casing. The PEN wire from the power line is connected to the latter. As tires, pieces of copper tape are used, the cross section of which corresponds to the maximum current strength. Then a jumper is installed between the two buses, and the shield itself is connected to the ground loop. The phase wire is mounted on a separate insulated bus.

TT connection

This type of protection does not require any separation of the PEN wire. As in the previous case, the phase wire is attached to a separate insulated bus, and the PEN conductor combined with the working neutral is connected to another bus isolated from the shield. In the future, it is considered an ordinary neutral wire. The ground loop is connected to the metal casing of the cabinet, so it is not connected to the PEN wire.

Grounding connected according to the TT scheme assumes isolation of the N and PE lines

Due to the features of this connection, there are advantages in comparison with the TN-C-S scheme:

• when the PEN conductor combined with the working neutral burns out, the case of any consumer will not be energized (the potential will be zero);
• the lack of communication between the zero of the network and the protective wire makes it impossible for a situation where a phase imbalance voltage appears on the electrical equipment case.

Skeptics may argue that the cases described above will trigger the residual current device (RCD), which is equipped with almost all protective systems today. However, do not tempt fate and rely on electronics - it is better to provide yourself with double protection. It should be noted that due to the need for additional voltage relays and RCDs, the TT system is more expensive for consumers than TN-C-S, so when choosing it, one must be prepared for additional expenses.

Video: TN-C-S and TT earthing systems

Do-it-yourself installation of a ground loop

Work on the arrangement of the ground loop is carried out in stages, starting from the design and calculation of the system and ending with the installation of the loop.

Choosing a working scheme

At the first stage, it is necessary to decide on the scheme according to which the grounding of a private house will be built. There are mainly two types of systems in use today:

In addition, the rods can be driven in any arbitrary way - in the form of an oval or a rectangle. The main thing is that the requirements regarding the reliability and resistance of grounding conductors are observed.

Calculation of the parameters of the ground loop

Grounding parameters are determined based on the maximum resistance of the "ground" loop, which should not exceed 4 ohms. Experts recommend counting the protective system on the resistance of an artificial ground electrode equal to 1 ohm.

At home, it is very difficult to carry out a full-fledged design, since a fundamental approach requires the determination of many parameters - soil resistivity, taking into account its freezing and dehydration, spreading resistance, changes in soil moisture, etc. In principle, such a serious approach is required for industrial power plants. On a private courtyard, you can use a simplified method.

To determine the parameters of the vertical circuit, the formula P1 = 0.84 × p / L is used, where P1 is the resistance of the circuit in Ohm, p is the resistivity of the soil, Ohm × m, and L is the length of the pin, m.

For cases involving the use of several vertical ground electrodes, the parameters of individual rods are calculated P = P1 / 0.9 × m, where P is the resistance of a single rod in Ohm, and m is the number of ground electrodes in the circuit.

In these formulas, the "dark horse" is only the resistivity of the soil. Knowing its value, using the first formula, it is easy to calculate the resistance of the circuit. By substituting this value into the second equation, the required number of ground electrodes is obtained with the chosen length of each electrode.

If it is not possible to determine the resistivity of the soil using special equipment, then you can take the data from the table for any type of soil.

Table: soil resistivity

In addition, a practical method can be used to determine the soil resistance in the area selected for the installation of a ground loop. To do this, the electrode is driven into the ground, periodically measuring the resistance. If, upon further immersion, its value has ceased to change, then it is considered that the rod is at a depth where the resistivity of the soil remains constant. Further, this ground electrode is connected to other electrodes of the circuit, which are installed in a similar way.

We determine the place of installation of the protective structure

Before proceeding with the installation of a protective structure, a flat area is selected, which is at least 1.5 m and not more than 10 m away from the house.

The place for the ground loop should be close to the house

When placing a structure, the following rules are followed:

1. It is forbidden to install a ground loop in places where people or animals regularly stay, since when current is drained into the ground, living beings fall under the action of step voltage. If it is not possible to comply with this rule, then the site must be protected.
2. It is better if the grounding device is installed on the north side of the house - as a rule, the soil there is damper, which means that contact with the rods will be better.
3. It is not recommended to install system elements near thermal engineering systems, since excessive drying of the soil increases the resistance of the circuit.
4. The electrodes are mounted below the freezing point of the soil. The minimum installation depth of ground electrodes is 0.5 m.

Too wet soil on the selected site has a positive effect on the resistance of the system. In such places, grounding works best, but there is a danger of rapid corrosion of the rods. In this case, electrodes of increased thickness are used, as well as rods coated with special conductive materials.

Painting or coating of ground electrodes with paint or other protective compounds that reduce current conductivity is prohibited. This will lead to an increase in the resistance of the circuit, which will negatively affect its performance.

What tools and materials will be needed

To build your own grounding system, you should prepare the following materials:

• a steel corner 50x50 mm, a pipe with a diameter of at least 32 mm with a wall thickness of 3.2 mm or a bar with a thickness of 10–12 mm - three segments of the estimated length;
• a metal bus with a cross section of at least 40x4 mm - three segments of 120 cm each and one strip length from the installation site of the circuit to the electrical panel or entry point to the house;
• bolt with nut M8 or M10;
• copper conductor with a cross section of at least 6 mm 2.

If you are interested in making a ground loop, then most likely you will find the following tools in your workshop:

• welding transformer or semiconductor inverter;
• angle grinder, which we call the "grinder";
• electric drill and metal drills Ø 10 mm or Ø 12 mm (depending on the diameter of the bolt used);
• circle for cutting metal;
• bayonet shovel;
• sledgehammer;
• perforator or impact drill;
• roulette.

After the necessary materials and tools are prepared, you can proceed to the construction of grounding with your own hands.

Excavation

Circuit installation

The assembly of the ground loop is the main part of the process, so the installation is carried out in strict accordance with the previously developed project.

1. After all the rods are driven into the ground to the desired depth, their ends are welded to form a metal frame in the shape of a triangle.

   The connection of the pins to each other is carried out by welding

2. According to the adopted scheme, electrodes are driven into the ground at the corners of a triangular trench. To facilitate the work, one end of the ground electrodes should be made sharp. To do this, the grinder cuts off the metal, getting a semblance of a spear or arrowhead.

   Ground electrodes must have sharp edges

3. The minimum depth to which the ground electrodes must be driven into the ground is 2 m. The tops of the pins must remain on top in order to be able to connect them by welding.

   To connect the rods into a closed system, instead of a steel strip, you can use metal corners

4. A separate tire is placed in a trench that leads towards the house, after which it is welded to the nearest rod. At its other end, drilling Ø10–12 mm is performed in a metal strip. Using a bolt and nut, the ground cable is attached to a metal bus, after which the structure is covered with soil.

   Reliable connection of the ground loop to the cable is obtained using a threaded connection

To increase the current conductivity of the soil, the places where the electrodes are installed are watered with a solution of kitchen salt in water. Being an excellent electrolyte, saline solution helps to reduce the resistance of the circuit. The disadvantage is that this mixture is also a good oxidizing agent, so the metal begins to actively rust, and the resistance of the system grows. However, this method can be used without problems in systems with stainless steel bars and electrodes.

Checking the correct installation

The inspection is carried out after the completion of the installation work. If there is access to special equipment, then you can use devices such as TN-200, EP-183M, Extex GRT300. Their principle of operation is based on measuring the resistance value between ground electrodes and two electrodes buried in the soil. For this:

1. Complete rods are driven into the ground to a special mark or to a depth of more than 50 cm and clean a small area on the tire.
2. According to the instructions, the device is connected to the pins and the connecting bus, after which the readings are taken. In a 220 V network, the device should show a resistance of no more than 4 ohms, and for a three-phase system, even less - up to 2 ohms.

The correctness of installation is checked with special devices - ground resistance meters

When using the ground resistance meter M-416, the electrodes are stuck into the ground at a distance of at least 10 m from each other and more than 20 m from the nearest ground electrode.

If you don’t have access to such precise instruments, then you can check the operability of grounding for 220 V networks in the old “old-fashioned” way, which, nevertheless, can give an answer about the suitability of the design you made.

1. They take a 100 W light bulb with a cartridge to which two stranded conductors are connected.
2. Their ends are cleaned and plugged into the outlet - the light should be brightly lit.
3. After that, using an indicator screwdriver, they determine which socket contact corresponds to the phase and connect an impromptu “probe” to this output and the ground loop.

You can check the performance of the grounding system using an incandescent lamp

If the light at the same time is no less bright than when it is connected to a 220 V network, then everything is done correctly. A dim glow indicates high resistance or poor contact between the individual elements of the ground loop. If the light does not light up at all, then this indicates a break in the system or improper installation.

Video: how to build a reliable grounding of a private house with your own hands

A grounding system must be equipped in every home. Installing a protective circuit with your own hands is not some kind of overwhelming task. All that is needed to solve it is the correct calculation and accurate installation. It is only important not to forget about the safety rules when carrying out work related to a voltage of 220 V or 380 V. If you are not confident in your abilities, then the system check should be entrusted to a familiar electrician or a person well-informed about where to look for that very “phase ".

Quite often, owners of private houses say that if there is a “good” zero, it’s useless. But this is a rather dangerous delusion - after all, the "earth" provides additional protection not only for household appliances, but also from electric shock to a person. Today we will consider the possibility of making 220 V grounding in a private house with our own hands, we will try to understand how it differs from 380 V, and we will also figure out how difficult this work is. But the main question to be solved is whether grounding is really so important and necessary.

Read in the article:

What is grounding for and how necessary is its installation in a private house

Let's start with what almost all owners of household appliances often face - a slight but sensitive electric shock from the body of some device in the house. And this happens from breaking the insulation and touching the current-carrying parts with the body of the device.

Let's consider another option. Sometimes it happens that by opening a water tap, a person feels a tingling electric current from the water. The neighbors who are trying to steal electricity are already to blame for this. Of course, with newer metering devices, such a number will not work, but with the old ones it worked out quite well. This happens due to the fact that an unscrupulous consumer, having taken the phase for the device from, connects zero to the water pipe. In this case, the consumption drops by 2 times.

Important information! If the consumer is convicted of such theft, then he will definitely face administrative punishment.

So, returning to our topic - why do we need grounding. It is it that will save you from such unpleasant sensations, and sometimes from more serious electric shocks. We will not consider its device in apartment buildings - after all, a common circuit is mounted there. It is to him that all living quarters are connected. It will be much more interesting to deal with grounding for a private house, which you can mount yourself.

The main task is to understand how to do this kind of work. Moreover, usually old household appliances are taken to the dacha, which require special attention. It is the installation option in such areas that will be a priority for us. But first, let's analyze the general concepts and nuances that grounding has in the country.

The concepts of "grounding" and "zeroing": what is the difference between them

The fundamental difference between these concepts is as follows. Grounding reduces the voltage in the damaged circuit to a minimum that is not dangerous to humans. Zeroing, with the help of automation, turns off the power supply in the event of a short circuit. The danger of the second is that the automation may not have time to work, and the person will receive an electrical discharge that is dangerous to health or even life.

In houses where it is not possible to install a ground loop, a neutral wire is sometimes used as this, but in this case it is necessary to install protective shutdown devices and automatic machines together, or to install difavtomatov. But most often there is a possibility of grounding and lightning protection in a private house, which means that you need to understand the technology of installation and operation.

Related article:

What to avoid when installing a ground loop - the most common mistakes

Of course, when installing the ground loop with your own hands for the first time, mistakes cannot be avoided. You can say more - they are allowed even by experienced craftsmen. But, as they say, "forewarned is forearmed." That is why it is worth mentioning the most common of them.

Expert opinion

Engineer-designer of ES, EM, EO (power supply, electrical equipment, interior lighting) ASP North-West LLC

“Ground from the loop cannot go directly to the device. Grounding must come to the device from the bus located in the power shield. That is why the first and most common is, of course, the wrong connection.”

The next mistake is the use of a gas supply or sewer pipe as a circuit. Under no circumstances should this be done. The rules for the installation of electrical installations also speak of this. Also, the metal fence around the house cannot be used as an outline.

Another common mistake is using too thin conductors (tires and electrodes). This will lead to very rapid corrosion and decay of the metal, nullifying all the work. Just as important is the length of the welds when installing the ground loop. This parameter should not be less than 10 cm (for example, the connection of two tire sections). As for the connection of the tire with the electrode, it is necessary to boil the place of contact along the entire length and on both sides. Welded seams must be treated with an anti-corrosion compound. But this does not apply to the entire ground plane.

Further. The grounding strip, which is located above the ground level and on which the contacts for connecting the grounding wire are fixed, must be painted (preferably black). In this case, the composition of the paint material does not matter. It can be either nitro paint or any bituminous mastic. It is also desirable to apply a “grounding” sign to the wall in this place (see photo).

Also, electrodes should not be made smaller than 1.5 m. This will lead to a loss in the quality of the entire ground loop. Also, you can not leave the tire on the surface or with a small depth. The depth of the ground bus should be 0.5-0.8 m. This is a must!

One more thing. Many, by conducting ground from the bus contacts to the power shield, make the wire long. After that, they have to twist it into a spiral in order to achieve the required size. This cannot be done. Surely someone remembers from a school physics course that any coil of wire is already a coil that creates inductive currents. And in the grounding system, any inductance is unacceptable.

Installation of grounding for a lightning rod in private homes

There are quite a lot of disputes in our time around whether lightning protection is needed for private houses. And yet, most tend to believe that it is necessary. Moreover, its device will not require a lot of time, effort and money. Let's figure out what is needed for this. You will need the following material:

• three iron electrodes, 1.5-2.5 m long;
• iron bus for connecting pins;
• steel wire rod, with a diameter of 6-8 mm 2 for grounding to the lightning rod;
• copper single-core wire, with a cross section of at least 6 mm 2 and a length of 1-1.5 m as a lightning rod;
• wooden support for mounting a lightning rod, 3 m long.

Now you can get to work.

Important! The ground loop for the lightning rod should be located at a distance of 5-8 m from the entrance to a private house.

At the required distance, we dig a trench 0.5 m deep in the form of an isosceles triangle with edges of 1 m. We hammer electrodes in the corners and perform the same actions as with home grounding. The difference is that a steel wire will go from the circuit to the house as a down conductor.

Now a wooden support is attached to the roof, on top of which a copper lightning rod is fixed. The wire rod should come to him. At the same time, when mounting the wire along the wall and along the roof, it makes sense to lay asbestos fabric between it and the surface as an insulator. As you can see, the process is not complicated at all and will take a little time. If desired, you can make a lightning rod on a tower, separate from the house. At the same time, you should be prepared for the fact that its length should be 3-4 m above the roof ridge.

Well, now, having figured out how to make a lightning rod in a private house, you can move on to the cost of ready-made kits for grounding installation, as well as clarify the prices for such work when hiring professionals.

The cost of grounding kits for private houses

Many do not know that grounding kits for giving can be purchased ready-made. Let's try to figure out what is included in them, in what quantity and how much it can cost. In addition to the main supplier to the Russian market - the Polish company ZANDZ-GALMAR, it makes sense to pay attention to the Russian manufacturer - the company Elkom.

Company manufacturer	Name	Quantity, pcs.	The cost of the set, rub.
ZANDZ-GALMAR	Stainless steel rod steel 16mmX1.5 m	4	24 000
	Coupling for connection	4
	Tip	1
	impact head	1
	Conductive paste 0.15 gr	1
	Insulating tape	1
	conductor clamp	1
Zandz ZZ-000-015, universal grounding kit 15 meters (Galmar)
Elkom	Stainless steel rod steel 14mmX1.5 m	4	5800
	Coupling for connection	4
	Tip	1
	impact head	1
	Conductive paste 0.15 gr	1
	Insulating tape	1
	conductor clamp	1
Earthing kit "ZN - 6", galvanized

As for the cost of grounding installation in private houses, it varies from 10,000 to 15,000 rubles. Of course, the cost of Russian-made kits is significantly lower. It is for this reason that some people buy grounding for a private house, the price of which is 5-6 thousand rubles. Much easier than making it yourself.

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