Diameter of the portable grounding rod. How to make grounding at the dacha: do-it-yourself grounding with metal parts
Modular grounding- this is a project created specifically for the installation of grounding conductors on residential properties, for example, such as private country houses, country houses, as well as for industrial and administrative facilities.
Practice of installing a modular grounding loop.
A modular ground electrode is a prefabricated structure consisting of steel pins specially treated with copper, each 1.5 meters long. These pins are combined into a single grounding circuit for grounding the object.
The length of the prefabricated grounding rod can reach a depth of about 30 - 40 meters. The 1.5 meter grounding pins have threads at the ends, through which and connecting couplings between them, it becomes possible, as the assembled grounding pin moves deeper, to extend it with the next pin, etc.
Installation of a vertical grounding pin in depth is done as follows. The first pin is equipped with a steel tip at the bottom, and on it top part The mounting coupling with the attachment for the vibrating hammer is screwed on. A hammer or hammer drill is used to strike the nozzle, and a special clamp is used to hold the pin in a vertical position.
When the first pin enters the ground to a length of approximately 1.3 - 1.4 meters, the mounting coupling with the attachment for the vibrating hammer is removed, and instead of them, the second pin is screwed through the coupling. A special clamp to hold the pin in a vertical position moves up the newly mounted structure, and its top is again equipped with a mounting sleeve and a hammer attachment, and the process of driving in the grounding pin continues.
The circuit of the modular grounding pin is shown in the diagram below, where:
1. Attachment for a hammer or vibratory hammer.
2. Mounting coupling.
3. Clamp to hold the ground rod in a vertical position.
4. Coupling coupling.
5. Ground rod.
6. Steel tip.
Several such modular grounding conductors are installed for the grounding loop (according to the design), and then they are connected to each other, by means of a copper strip or wire using clamps, into a single grounding loop. When installing clamps, these places are pre-treated with conductive paste, and after complete installation of the entire grounding loop, it is subjected to anti-corrosion painting.
Measuring the resistance of a mounted vertical pin is possible at the installation stage of each newly screwed 1.5 meter pin, and the service life of such a modular grounding loop is approximately 30 years.
Advantages of modular grounding.
This is a drawn steel rod with a diameter of 14 mm and a length of 1.5 meters, coated by electrolytic deposition (electrolysis) with copper of 99.9% purity, forming a coating with a molecular and inextricable bond with the steel.
Threads are applied along the edges using the knurling method for their mutual connection using a coupling.
In addition to electrical conductivity, high-quality steel in such a grounding device also plays a mechanical role necessary for burying the electrode in the soil. The pins have a high tensile strength (600 N/mm²) and can be driven into the ground with a jackhammer to a great depth - up to 40 meters.
The thickness of the copper coating is at least 0.25 mm along the entire length of the rod (including threads). This guarantees its (coating) resistance to bending, peeling, and scratching during installation. This is especially important on threads, where more thin layer copper will be completely destroyed from loads and friction with the coupling during deepening (installation) *.
These features guarantee the high corrosion resistance of the ground pin and provide such long term service (up to 100 years).
* Features of creating threads
The “correct” thread is applied AFTER copper plating - by knurling, because only this method allows you to achieve high overall quality pin.
An alternative “technology” for copper plating of pins: with already formed threads (before applying the coating) is cheaper, BUT it shows a worse (and dangerous during operation) result.
This is due to a feature of electrolysis: thickening of the coating in the recesses/cavities, due to which the base material (steel) on the thread can only be coated with a thin (0.03 - 0.05 mm) layer of copper.
Such a thin coating is easily damaged during installation by impacts and friction in the coupling. Subsequently, when the grounding electrode is used with such violations, pockets of electrochemical corrosion (“copper-iron”) appear, leading to its complete destruction within 2-3 years.
Copper plating technology
The key to making a quality ground pin is to create a strong, uniform copper coating on the steel workpiece. required thickness with minimal impurities.
On a separate page "Copper-plated steel" are presented detailed description main characteristics, manufacturing processes and tests of the coating.
Comparison with galvanized pins
From 1910 to 1955, The National Institute of Standards and Technology (NIST) conducted an extensive study of underground corrosion, during which 36,500 samples representing 333 types of ferrous and non-ferrous metal coatings and protective materials were tested at 128 locations throughout the United States*. This study is widely regarded as one of the most comprehensive corrosion studies ever conducted.
One of the results of this study was the fact that a ground pin coated with 254 microns of copper retains its specifications for over 40 years in most soil types. And rod electrodes coated with 99.06 microns of zinc in the same soils can retain their qualities only for 10-15 years.
In addition, the protection period zinc coverage decreases in proportion to the increase in the amount metal structures in the ground located next to the electrodes (than more designs- the shorter the coating lasts / the faster it “disappears”). Examples of these structures can be: reinforcement of building foundations, pipes, etc.
Grounding pin with copper coating 254 microns thick, extracted from soil (loam) after 10 years
Grounding rod with zinc coating 99 microns thick, removed from soil (loam) after 10 years
Another study of the corrosion properties of copper coating was carried out by the Polish company GALMAR. Artificial aging samples under conditions simulating aggressive soil (an “acidic” swamp), showed that a grounding pin with a 250 micron copper coating retains the necessary technical characteristics for at least 30 years.
Modular grounding is a technically advanced method electrical connection conductive material with soil. Another name for the technology is the modular-pin system.
This article will discuss the advantages and options for installing this type of grounding. Attention will also be paid to the issue of controlling loop resistance.
Modular-pin grounding system
This system consists of vertically arranged steel rods and couplings (shown in Figures No. 1 and No. 2). The length of each rod, coated with a copper layer, is 1.5 meters. Brass couplings are used to fasten the rods to each other.
Ground rod Technical specifications:
- part length – 1500 millimeters;
- rod diameter – 14.2 millimeters;
- thread: 5/8” (double-sided, copper plated);
- thread length – 30 millimeters;
- weight – 1.85 kilograms.
Technical specifications:
- material – brass L63 (bronze can be used);
- length – 70 millimeters;
- diameter – 22 millimeters;
- internal thread – 5/8”;
- thread length – 60 millimeters;
- weight – 114 grams.
The package includes a brass clamp, which is used to fasten the vertical and horizontal elements of the ground loop. As vertical element a steel rod protrudes, and the horizontal one - copper wire from the switchboard or a strip of steel.
As can be seen from Figure No. 4, the equipment set includes two types of steel tips. They are screwed onto a rod that is installed vertically in the ground. Tips are designed for different types soils: for special hard soils and for ordinary soils.
Technical specifications:
- tip length – 42 millimeters;
- steel tip diameter – 20 millimeters;
- internal thread – 5/8”;
- thread length – 20 millimeters;
- weight – 45 grams.
In addition to the main device, a landing pad is supplied (shown in Figure No. 5), as well as a special nozzle (Figure No. 6). These devices will be needed to apply and transmit the movements of the vibratory hammer.
Technical details:
- length – 53 millimeters;
- diameter – 23.6 millimeters;
- external thread – 5/8”;
- thread length – 35 millimeters;
- weight – 110 grams.
Impact attachment - length – 265 millimeters;
- diameter of the main part – 18 millimeters;
- diameter of the working part – 11.7 millimeters;
- the length of the working part is 14.5 millimeters.
In addition, the main kit includes an anti-corrosion conductive liquid paste(Figure No. 7). It is designed to prevent corrosion. The package also includes a protective tape (Figure No. 8), which is used to clamp the system elements vertically and horizontally.
Anti-corrosion electrically conductive lubricant Conductive paste based on graphite allows you to achieve a constant electrical circuit of the vertical grounding electrode. This paste composition can be used regardless of the seasonal factor. The threads of all used connections are treated with lubricant.
Anti-corrosion paste has good adhesion and resistance to high temperatures. In other words: the paste does not flow when heated. The use of lubricant can reduce the resistance of the joint by 9-10%.
The tape is used to prevent corrosion on pipes (regardless of their location), as well as on any other metal elements designs. Anti-corrosion tape is flexible even with high temperatures, as well as acid resistance, resistance to alkaline and salty environments. The tape is not afraid of harmful microorganisms and moisture.
It is more convenient to carry out assembly work using a vibrating hammer (Figure No. 9). The spreading resistance is controlled by a resistance measuring device (Figure No. 10).
Resistance measuring device Installation work
Do-it-yourself installation consists of several successive steps, which will be discussed below.
Meter Installation
We place the device for measuring resistance near the place where the ground loop will be installed. As a location, we choose a hole with a height, width and depth of 200 millimeters for each parameter. The pit should be located one and a half meters from the wall of the building, where the horizontal element of the ground loop is located. The element can be copper wire or a strip of steel.
To carry out measurements, you will need measuring electrodes, which we install with an indentation of 25 and 10 meters along different sides device. We hammer the electrodes into the ground and connect them to the measuring device.
Electrode installation diagram
Installing the first module pin
- Screw the tip onto one side of the rod. Before screwing, the tip must be treated with anti-corrosion lubricant.
- We screw the coupling onto the other rod end. It is also treated with an anti-corrosion compound.
- We install the landing head designed to apply pressure from the vibrating hammer.
- We install the assembled rod (tip down) as deep as possible into the ground in the hole.
- We turn on the vibrating hammer, point it at the rod site and hammer the rod into the ground in about 15-20 seconds. In this case, we leave 20 centimeters on the surface so that the rods can be connected to each other.
Intermediate resistance measurement
We remove the landing pad and measure the resistance. To achieve the required resistance, you need to deepen the vertical pins by installing grounding sections on top of each other.
Installing other vertical pins
- After treating the coupling with lubricant, screw another copper rod into it.
- We put another coupling on the rod and install the landing head again.
- We repeat the operation with a vibrating hammer.
- Checking the resistance to spreading.
We increase the rods until the resistance drops below 4 ohms.
Installation of a horizontal ground electrode
- We begin to connect the vertical and horizontal conductive grounding elements. To connect a steel strip or copper wire to a rod, use a brass clamp. One side of the clamp is adapted for a pin, the other for copper wire or steel strips.
- We fix the clamp with bolts on the rod.
- We screw the horizontal part of the grounding to the clamp. The horizontal component is separated from the pin by a separating plate, which avoids bimetallic corrosion.
- We apply anti-corrosion tape to all bolted connections (Figure No. 12).
Deep modular-pin grounding system The grounding loop, manufactured according to the modular-pin system standard, can be made in both single-point and multi-point versions. The specific choice depends on the task at hand - the required resistance of the grounding conductors.
Advantages of modular pin grounding
Figure 13 shows the relationship between spreading resistance and ground rod depth. The commissioned grounding system made it possible to achieve a spreading resistance of approximately 4 ohms in less than an hour.
Graph of grounding resistance versus depth at which the rod is located.
Let's figure out what conditions are needed installed system. To install a grounding loop using the pin method you need:
- a vibrating hammer that will make the installation process easier for the installer;
- measuring device;
- another installer who will act as an assistant holding the rod while operating the vibratory hammer.
The following are the advantages that modular grounding has over the most commonly used standard ground loop:
- The area on which the modular-pin system was located occupied no more than one square meter, which indicates the possibility of compact installation.
- No need for labor intensive earthworks ah thanks to the use of a vibratory hammer.
- Not needed welding work, since all connections in the modular-pin system are made using couplings.
- Long service life of the system (over 30 years) due to coatings resistant to corrosion processes (indicates resistance to corrosion of soil and electrolytic origin).
- The use of a deep modular-pin design eliminates the dependence on soil characteristics.
- The design does not contain any complex elements; even a less-trained person can assemble it.
Another issue worth mentioning is the cost of the system. Overall costs are approximately equivalent to US$500. The installation cost will add another $120 to the cost. At the same time, a classic grounding system will cost approximately $240, including installation work. However, despite the loss in price terms, the advantages of the modular-pin system listed above clearly indicate its favor.
When the grounding loop is installed, you will need to draw up the appropriate documentation for it, including a measurement protocol, a grounding passport (with a diagram included in it) and a hidden work report. Documents must be kept throughout the entire life of the system.
The device of the so-called buried grounding loop externally consists of electrodes - metal rods that are driven into the ground and connected to each other. The most effective design is considered to be one in which the electrodes are arranged in one line. However, when favorable conditions A design in which the rods are arranged in a triangle will also work quite well.
Grounding device if the pins are located in one line
Grounding device in case of pin arrangement in the form of a triangle
The arrangement in a triangle is somewhat worse, since the electrodes shield each other much more, which means that the material consumption when organizing such a design, all other things being equal, will be greater. On the other hand, at a short distance, the triangular arrangement significantly reduces the number of excavations, and it is much more convenient to connect the pins with the bus together in a triangular-shaped pit than in a narrow trench. 
Design of a deep grounding loop using an angle: 1. Angle made of steel 50 by 50 by 5 millimeters, 2. connecting strip of steel 50 by 5 millimeters, 3. Steel grounding bus 50 by 5 millimeters.
The distance of the ground loop from the house walls must be at least 1 meter.
Grounding electrodes should be buried to a sufficient depth for possible soil freezing. The thing is that, when frozen, the soil conducts very poorly. electricity. In particular, when the topmost soil layer half a meter high freezes, its resistance increases approximately ten times, and at a depth of about a meter - three times. In summer, the surface layers of the soil (up to about a meter deep) dry out noticeably, which quite sharply increases its resistance. That is why it is necessary to bury the electrodes deeper into the so-called stable soil layers, which lie at a depth of 1-2 meters. At this depth, soil parameters remain almost unchanged throughout the year.
Of course, it is quite possible to take longer metal electrodes, but this will increase material consumption. The calculation of the grounding loop is given in the article entitled “Grounding Calculation” on our resource. In addition, it is worth noting that manually driving grounding rods over 2.5 meters long into the ground can be quite problematic.
Table 1 Coefficients for using 3 electrodes placed in a row 
Construction fittings are not suitable for grounding rods
Table 1 shows how the distance between the 3 rods affects the coefficient of their use. The distance ratio between the rods is the ratio of the rod length used to the distance between them. For example, if you take a pair of electrodes 2.5 meters long, completely buried in the ground to the required freezing depth (their entire length is used) and place them at a distance of two and a half meters from each other, then their ratio will be 1 = 2.5 /2.5.
Looking at the table, we can conclude that the most optimal distance between the ground loop rods is usually equal to their length. With an increased distance, the effective increase will be small at quite large volume work on the ground and the consumption of material for connecting the rods with a tire.
For the production of depth electrodes, you can use any materials having the minimum dimensions indicated in Table 2.
It should be noted that Table 2 does not contain reinforcement with the so-called periodic profile, which is usually used for concrete reinforcement. Rods of this kind of reinforcement are completely unsuitable for deep grounding, since when driven into the ground, they loosen it near them, which leads to an increase in resistance.
Table 2 Minimum dimensions of grounding electrodes from the point of view of mechanical and corrosion resistance
Material | Surface | Minimum size |
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Diameter, mm | Sectional area, mm 2 | Thickness, mm | Coating thickness, microns |
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Black 1 metal without anti-corrosion coating | Rectangular 2 | |||||
Hot-dip galvanized 5 or stainless steel 5,6 | Rectangular | |||||
Round rods for recessed electrodes 3 | ||||||
Round wire for surface electrodes 4 | ||||||
Copper sheathed | Round rods for recessed electrodes 3 | |||||
Electroplated copper plated | Round rods for recessed electrodes 3 | |||||
Uncoated 5 | Rectangular | |||||
Round wire For surface electrodes 4 | ||||||
each wire | ||||||
Tinned | each wire | |||||
Galvanized | Rectangular 9 | |||||
1 Service life 25-30 years at a corrosion rate in normal soils of 0.06 mm/year. 2 Rolled or cut strip with rounded edges. 3 Ground electrodes are considered to be buried when they are installed at a depth of more than 0.5 m. 4 Grounding electrodes are considered to be surface electrodes when they are installed at a depth of no more than 0.5 m. 5 Can also be used for electrodes laid (embedded) in concrete. 6 Used without coating. 7 In the case of using wire manufactured by continuous hot-dip galvanizing, a coating thickness of 50 microns is adopted in accordance with current technical capabilities. 8 If it is experimentally proven that the likelihood of damage from corrosion and mechanical stress is low, then a section of 16 mm 2 can be used. 9 Sliced strip with rounded edges. |
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Galvanized clamps for fastening grounding conductors
Connecting a galvanized rod to a galvanized strip using a bolted clamp
In order to connect contour rods to the grounding bus and connectors, two methods are used:
In the case of using galvanized steel, a connection can be used without welding, using crimp threaded clamps. Moreover, the connection point must be protected from corrosion using an anti-corrosion bandage or coating with hot bitumen;
When using rolled black steel without any coating, it is connected using electric arc welding.
Carrying out anti-corrosion treatment of connections on clamps
Regarding the wire (the so-called protective conductor), which is connected directly to the grounding structure (that is, to the grounding bus), it is best to use a copper wire. The size of the minimum cross-section of the grounding wire should be selected according to Table 3. For example, if you simply connect a copper wire to a steel busbar using a galvanized threaded connection, and the connection is located in a plastic distribution box, the wire itself is hidden in a plastic corrugation, then this type of connection is necessary be considered poorly protected from corrosive effects, since it is in direct contact with air. However, the connection between a ground loop of this kind and a conductor is mechanically protected, which means the minimum possible cross-section of a copper wire will be 10 millimeters2. Details on arranging protective home grounding yourself are given in the article entitled “Installing a grounding loop yourself.”
Traditional grounding
Grounding pin
As can already be seen in the figure - arrangement of the ground loop on our own is not particularly difficult. Today there are two main methods of grounding. The first, which has already become traditional, is when three or more metal pins are driven into the ground to a depth of 3 meters. And more modern method, when one pin is driven into the ground to a depth of 30 m, i.e. to the maximum possible depth of the first aquifer.
1. Grounding using the traditional method
Select a location on the site as close as possible to the input cabinet (power panel). A distance of no more than 10 m is considered optimal.
To install the grounding loop, you will need a steel corner measuring 50x50x5 mm in the amount of 9 m and a steel strip measuring 4x40 mm in the amount of 9 m plus the distance from the grounding loop to the power panel.
We dig a trench approximately 0.5 m wide and at least 0.8 m deep. The trench is dug in the shape of an equilateral triangle (3 x 3 x 3 m) with a branch to the power cabinet.
Then, at the corners of the triangle, we drill 3 wells 3 meters deep and hammer in 3 corners of 3 meters each. If the ground is soft area, you can try to drive it in with a sledgehammer without drilling a hole. The end of the angle should protrude slightly from the ground so that a metal strip can be welded to it.
We weld a steel strip around the perimeter to three ground electrodes (corners) installed in the ground. We lead one end of the strip from the ground loop to the power cabinet. Weld the strip to the cabinet body.
Before filling the trench, we check the resistance of the ground loop. To do this you need to arm yourself with an Ohmmeter, for example: brand ES 0212 or any other similar. The resistance should not be higher than 10 Ohms (usually 4-6 Ohms). This is very little; for comparison, the average resistance of the human body is 7000 Ohms. If the loop resistance is higher than 10 ohms, drive another pin into the ground and weld it to the loop. Natural grounding agents ( metal poles fence, support, etc.) if they are connected to the circuit. Don't forget - all connections are made by welding.
The trench is buried with homogeneous soil that does not contain crushed stone and construction waste.
A properly made grounding loop will allow you to further install lightning protection, i.e. lightning protection.
2. Grounding with one pin
Grounding installation procedure
- Preparing the first pin.
Treat the inside of the starting tip with an anti-corrosion conductive lubricant and then put it on the pin.Treat the inside of the coupling with anti-corrosion conductive grease and screw it until it stops on the other side of the pin.
Screw the guide head for the jackhammer all the way into the coupling screwed onto the grounding pin.
Please note that the guide head must be screwed in until it makes full contact with the pin. This is necessary so that during installation the impact energy of the jackhammer is transferred through the head directly to the pin, and not through the coupling. Otherwise, the coupling may be destroyed.
- Drive the pin into the ground using a jackhammer (impact energy 20-25 J) to a level convenient for subsequent operations.
- Unscrew the guide head (without the coupling - it should remain on the pin).
- Once again treat the remaining coupling screwed to the pin with anti-corrosion conductive paste.
- Screw the next pin into it (the coupling from step 4) until it stops.
- Take a new coupling and process it inner part anti-corrosion conductive lubricant.
- Screw the guide head for the jackhammer all the way into this coupling (from step 6).
- Screw the coupling with the mounted head onto the pin connected to the already mounted pin (from step 5).
- Repeat steps 2 through 9 sequentially until you obtain the grounding electrode of the required depth.
Please note that when installing the last pin, it is necessary to leave on the surface the portion of this pin necessary for connection to the grounding conductor. - A clamp is installed on top of the mounted electrode to connect the grounding conductor.
- A grounding conductor (round wire or strip) is connected to the terminal.
- The connection point (clamp) is tightly wrapped with waterproofing tape.
ANDinformation about components modular grounding(on a separate page).
Conductor laying depth
P The surface layer of soil is subject to seasonal and weather influences. High humidity, freezing/thawing of the soil in this layer negatively affects both the grounding conductor and the grounding/connecting conductors located in it.
Moreover, the probability mechanically Damaging conductors in the surface layer during maintenance work creates inconvenience and increases the likelihood of creating a dangerous situation associated with an emergency grounding condition.
Nand in most parts of the Russian Federation and CIS countries, the depth of the surface layer of soil that is subject to the types of impact described above is 0.5 - 0.7 meters.
Therefore, the grounding and connecting conductors in the ground must be laid at this depth (0.5 - 0.7 meters) in a previously prepared channel.
Nand the vertical grounding electrodes are buried at the same depth.
Connection of ground electrodes
WITH The connection of the grounding electrodes with each other and the grounding electrode with the object is made with a steel or copper conductor (wire or strip).
M The minimum cross-sectional area of the grounding conductor depends on the tasks performed by the grounding conductor.
PThe conductor is laid at a depth of 0.5 - 0.7 meters in a pre-prepared channel (in which the electrodes are also installed).
DTo connect the grounding electrode to the conductor, use a special clamp included in the kit modular grounding ZandZ.
Sequence of work when installing grounding on site
- Dig a channel 0.5 - 0.7 meters deep in the place where the connecting conductor is laid
- Install grounding electrodes in the prepared channel. As instructions for installing grounding electrodes, you must use the list of operations “Procedure for installing grounding”
- Place the connecting conductor in the channel
- Connect the grounding electrodes to the conductor using the clamps included in the ZandZ kits
- Connect the resulting ground electrode to the electrical panel
- Fill the canal with soil