DIY grounding installation in a private house

In any country house or private building located within the city limits, the owners have at their disposal household appliances and power equipment, the use of which can lead to emergency situations. They usually manifest themselves in the fact that in some equipment the insulation is damaged, after which the supply voltage phase hits the metal case. If one of the residents accidentally touches it, he receives a strong electric shock, which can lead to irreparable consequences. To avoid such situations, protective grounding is organized in any modern building, designed to reduce the dangerous potential affecting a person during emergency operation of the equipment.

Is grounding necessary in a private house?

Reliable grounding in a private home is necessary, if only because the requirements of the PUE do not allow the operation of household appliances in it without protection from dangerous voltages.

Please note: In addition, unlike city apartments, in country houses a 4- or 5-core cable with a three-phase power supply of 380 Volts is allowed.

Such an input allows you to install a small milling machine on the site, for example, as well as connect asynchronous motors and other types of power equipment to the power supply line.

Grounding of all metal components in a private house

Grounding principle

To make it clearer why grounding is needed in houses or in the country, we need to consider the principle of its operation, based on the fact that electric current always chooses the shortest distance for drainage. In other words, electronic carriers always flow into circuits that have minimal resistance. In an emergency situation, when the current-conducting body of the device becomes energized due to insulation damage, this is precisely what happens. If this has already happened, the only thing that can protect the user working with them is the presence of a chain to drain dangerous current.

Its branching can be achieved by installing a special grounding circuit (GC), the individual elements of which are connected to the housing of the protected electrical equipment. Thanks to this, the emergency current that poses a threat to humans is reduced to a safe value. The latter is explained by the fact that most of it flows into the ground along a parallel chain formed by the ZK design (see photo below).

The principle of operation of the grounding system

Important! The magnitude of the current component flowing through the human body largely depends on the isolation of his legs from the ground.

If you wear rubber shoes or a thick protective mat, it decreases in absolute value, ideally approaching zero. With this in mind, professional electricians usually work on equipment while sitting on a rubber mat and wearing rubber boots.

What is the purpose of grounding in a home?

Grounding is carried out for two reasons:

protection is the main reason for using grounding in home networks.
work - for the proper functioning of electrical devices (there are only a few devices in homes that require grounding to function properly, such as computer power supplies).

We are mainly interested in security, which gives rise to another question: how does an iron pin buried in the ground protect us from anything?

Let's assume that the earth (soil, soil) has an electrical potential of 0V (this is true in 99.99% of cases). Therefore, if you bury a wire in the ground, then there will be no electrical potential in all the grounded wires laid in the house and connected to it.

Next, we connect these wires to the devices through electrical connectors. Inside these devices, the protective (grounded) conductors are usually connected to the housing (metal) or to any other metal element that is easily accessible to humans during operation of the device and, therefore, should not be energized under any circumstances.

Since the case is connected to ground, whose potential is 0V, the case will have the same potential. If the housing has zero potential and zero potential approaches it, no current flows, that is, an electric shock will not threaten a person.

If the body of the device is not connected to the grounding wire and there is a breakdown inside for unknown reasons, an electric potential will arise, and since it is not connected in any way to the ground (directly or indirectly), it has nowhere to “escape”. Therefore, the risk is obvious: a person who has an electrical potential of 0 V, touching a body that has a potential of 220 V, actually becomes a conductor of current with this voltage, with all the ensuing consequences.

In total, as a result, the connection of all devices to ground prevents the long-term maintenance of electrical potential on the housings (and other elements) that are accessible to humans during normal operation of the device. In the event of an electrical fault in the frame where the latter is grounded, the formation of a short circuit will trip the circuit breaker (not to mention the residual current switch, if any) on the household distribution panel and cut off the power before anyone touches the frame.

Grounding schemes, which one to choose

Before making grounding in your private home, you will need to familiarize yourself with the features of the arrangement and operation of protective systems that involve the use of one of the well-known schemes. To do this, you need to consider the following important points:

When organizing the power supply of any modern facility, in addition to the neutral and phase buses, a so-called “grounding” conductor must be connected to it.
Its main purpose is to protect people from dangerous potential that enters the body of devices when the insulation of conductors is broken.
To do this, the grounding bus on the substation side is connected to a special grounding element (circuit), which is installed directly on its territory.

Additional information: Thanks to this, the protection function via the neutral core (combined with the working zero or via a separate conductor) is transferred to the consumer side.

At the same time, the grounding devices considered here in the house are usually classified as “repeated” chargers, duplicating station ones in case of a break in the neutral (combined PEN conductor).

According to the method of grounding the neutral core of the transformer at the substation and the facility on the consumer side, all used circuits are divided into the following two categories:

Firstly, these are systems with a solidly grounded neutral, which are the most common method of grounding transformers whose secondary windings are connected by a star. In this case, their midpoint is permanently connected to the circuit.
Secondly, circuits with the so-called “isolated” neutral are often used, in which the middle point is not connected to ground or is connected to it through the high resistance of the protection device.

a) a network with a solidly grounded neutral, b) a network with an isolated neutral connected to the ground through an arrester

Useful note: In the second case, the working windings of the transformer perform a separating function and are usually used for industrial purposes or in special electric heating installations.

Their use is associated with the need to isolate current-carrying parts of equipment from the ground loop. According to the rules of electrical installations, a solidly grounded neutral is usually designated as “TN”. One of the most common methods of protective use of such a neutral is to connect metal housings of devices to it via a separate bus.

Types of grounding systems (GS)

When studying the latest edition of the PUE, one immediately notices that Chapter 1.7 of the document provides the following list of protective circuits:

TN-C or a system with combined working and neutral conductors (English “common” means “common”);
TN-S or a circuit with separate routing of these buses (“select” or separate wiring);
TN-CS is a method that is a combination of the 2 previous approaches;
special schemes for connecting equipment to protective circuits with an isolated neutral, designated as TT and IT.

Basic grounding systems for electrical networks
The correct choice of a grounding system that is optimally suited for the specific operating conditions of equipment in a private home is another problem that requires an immediate solution.

Selecting a grounding system

It is recommended to resolve this issue at the design stage of a suburban building, that is, long before the construction of the object itself begins. The parameters of the electrical wiring installed in the building (selection of a set of electrical installation products, in particular) depend on which system of protection against electric shock is chosen. In a situation where a cable with two working conductors runs down to the house from a high-voltage pole, this means that the TN-C type grounding system is used in the supply.

A cable with two working cores runs down to the house from a high-voltage pole

Please note: In this case, re-grounding is mandatory, since the working and grounding conductors are combined (PEN).

Artificially splitting it on the input-distribution panel strip will allow you to isolate a separate PE wire, which can already be used to organize a local grounding loop. This type of protective system is obsolete and is used only in older buildings.

Connecting the house to the ground loop using the TN CS and TN-S system

If a major renovation of a private house is planned with a complete replacement of electrical wiring, the TN-CS system is chosen as a temporary measure. It can be used until local power grid services upgrade them and install a five-core power cable (with a separate grounding bus) to the region. By the way, in this case (according to experts), organizing re-grounding on a personal plot will not hurt at all. When implementing this scheme, a common or combined wire PEN is used on part of the route from the substation to the consumer, and on the supply to the facility equipment it is divided into PE and N.

The most expensive in terms of associated costs, but the most convenient and reliable in operation, is the TN-CS circuit. This is a TN-S type system operating in conjunction with transformers with a solidly grounded neutral. In this case, the PE and N conductors are separated along the entire length of the power line from the transformer substation to the consumer. That is, they come to it as two independent buses: a zero working N and a zero protective PE wire. As already noted, to guarantee the security of the facility itself and the people working in it, the PE grounding wire can be connected to a circuit located near a private home. In this case, there are no particularly stringent requirements for the contract itself.

However, if you have this system, you will have to put up with its characteristic disadvantages, which are as follows:

Electrical wiring throughout the house and outbuildings should be laid with a three-core wire.
If you have a 3-phase power supply of 380 Volts, you will need a cable with 5 cores.
In this case, the cost of components and materials increases significantly.

Important! On the other hand, when operating such a system, the safety of working with the equipment being serviced increases and the arrangement of re-grounding is simplified.

Modern power supply lines (both overhead and cable) are laid only using a five-core cable protected by the TN-S system.

TT system

TT grounding system
This system is most popular for grounding private houses, cottages and country houses.

The peculiarity of this method of protecting equipment and people working on it is its use only in situations where no other grounding system is suitable. In this case, the neutral core of the substation transformer does not have direct electrical contact with the grounding busbar, which in turn is connected to a separate grounding loop.

Important! That is, in this system, the neutral network wire (the so-called “neutral”) is not connected to the grounding circuit installed on the consumer side.

Specific situations when the choice of a TT system will be required are described in detail in the current regulations (PUE, paragraph 1.7.59, in particular).

Important! Since the drain current that occurs in an emergency situation may be insufficient to trigger the usual protection, according to paragraph 1.7.59, an RCD or an RCD is additionally installed in it.

Close to TT in design is the IT system, which can be examined in detail in the next section.

Connecting the house to the ground loop using the IT system

IT system
This method is used if the neutral of the substation transformer is completely isolated from the ground. Alternatively, it can be connected to it through a spark gap, the resistance of which is high at low voltages and decreases sharply when they increase above the limit level.

Additional information: This device reliably protects station electricity consumers from primary voltage entering the secondary part of the winding.

In such a connection circuit, the power network supplying power to electrical installations lacks not only the neutral wire N, but also the grounding bus PE. At the same time, they do not have single-phase voltage in the literal sense of the word. All consumers connected to such a line receive a linear voltage of 380 Volts, operating between phases A, B and C). Due to the fact that the short-circuit currents in this system, like the previous case, are not very large, the use of RCD devices or differential circuit breakers is considered mandatory.

To conclude this section, we note that in nature there are no grounding systems that would be universal and suitable for all occasions. Each of them has known pros and cons, nevertheless fulfilling the main task - creating the safest working conditions for service personnel and ordinary energy consumers. A competent approach to choosing the type of system protection is impossible without a clear understanding of what it is intended for and how it works in power lines.

Connecting the circuit according to the TN-CS scheme

A do-it-yourself grounding system for a private house according to the TN-C scheme is, as a rule, a two-wire wiring in which one wire is a phase, the second neutral performs two functions at once: a working conductor N and a protective conductor PE. To convert to the TN-CS circuit, it is necessary to install an additional bus inside the distribution panel. It must have metal contact with the electrical panel housing. The neutral wire of the power supply network and the conductor from the new ground loop, assembled with your own hands, will be connected to it.

The new bus must be connected to the bus to which the neutral wire N coming out of the house was connected. In this case, there should be no contact between bus N and the shield. In fact, this will happen, because a dielectric terminal block is installed in the panel on the bus, through which the connection is made. By the way, the phase wire is also insulated from the elements of the distribution board and its housing.

The last step in how to properly ground a private house using the TN-CS system is to connect a new busbar and a ground loop. Typically, a multi-core copper cable with a cross-section of at least 4 mm² is used for this, one end of which is attached to the shield, the other to a bolt welded to the end of the grounding conductor at the entrance to the house.

Types of ground loops

When arranging grounding loops in a house with their own hands, work performers can use the following options for their manufacture:

Preparation of a triangular structure with sides of equal length, selected depending on the requirements for the ground electrode.
Assembly of the protection system in the form of a linear (extended) structure arranged around the perimeter of the protected structure.
The use of the so-called “modular-pin” version.

Three types of grounding loop: triangle, linear circuit, modular-pin grounding
Let's consider each of these approaches to making grounding in private property in more detail.

Triangle

A grounding loop in the form of an equilateral triangle is the most common type of charger, most often installed in private homes. To manufacture it, you will need to prepare the following set of elements that make up the structure:

An equilateral triangle ground loop is the most common type of grounding device.

Three metal pins (rods) at least 2.5 meters long.
Steel jumpers connecting the rods into a single structure (they are prepared in the same quantity).
A thick copper or steel busbar required to connect the remote structure to the main grounding contact located in the distribution cabinet.

The plane of the triangular contour formed by steel strips with pins located at the corners should be located in a pre-dug trench approximately 50-60 cm deep.

Linear outline

This type of protective structure is installed in situations where several devices or pieces of equipment located at a considerable distance from one another are supposed to be connected to the charger. It is a linear structure consisting of a number of pins driven into the ground, the distances between which are calculated using classical formulas.

Linear diagram of a ground loop for a private house

From the resulting structure, similarly to the previous case, a branch (2) is made towards the distribution panel with the main grounding bus (GZSh). Before calculating such grounding, it should be remembered that the number of steel blanks used is limited by the characteristics of the spreading of emergency current. You can familiarize yourself with the parameters of the linear memory in the corresponding sections of the PUE.

Modular-pin grounding

The modular pin system is an example of a modern approach to solving a technical issue. It includes the following required elements in its kit:

Metal rods one and a half meters long with threads cut on their working part (the surface of these blanks is covered with a layer of copper on top).
Threaded couplings made of brass and serving as connecting elements for vertically driven pins.
Brass clamps are of a special design, ensuring the connection of metal pins with the bridging strip.
The tips of rods driven vertically into the ground.
A working attachment with an impact screw tip that provides impulse transmission from a vibrating tool (vibrating hammer).

Modular-pin grounding device for a private house

Please note: For reliable protection against moisture and subsequent corrosion, all connecting threaded elements are treated with anti-corrosion graphite paste included in the delivery set.

It is well preserved during the operation of the structure and does not spread when the elements are strongly heated, providing the required resistance to the spread of emergency current. The anti-corrosion tape included in its composition is highly resistant to aggressive solutions and reliably protects steel grounding elements from destruction. The remaining parts have a standard design and standard dimensions, determined by the assembly technology of the modular-pin design.

For information on how to make modular-pin grounding, read our article “Do-it-yourself modular-pin grounding: instructions, installation.”

Grounding device

In fact, grounding works extremely simply. From electrical lines, current enters your home through wires and then ends up in sockets. As a result, 3 wires should be connected to the outlet - 2 for electricity and 1 for grounding.

In multi-storey buildings, the grounding is usually connected to the distribution panel, which is on the site, and therefore you just need to connect the grounding line to it.

In a private house, you do everything yourself, and therefore if you need to ground a gas boiler, for example, one wire will not be enough for you.

Grounding consists of a wire that is connected to the panel, grounding pins and jumpers between them.

For grounding, you need three metal pins (this number is almost always enough), which, when receiving excess electricity from the network through a wire, will release it into the ground.

The diameter of the metal pin should be from 16 mm, and preferably 20 mm or more. It’s worth noting right away that the fittings are not suitable for this. This is because the reinforcement is hardened for strength, and when passing through hardened metal, electricity behaves a little differently.

If you can’t find rods on the farm, grounding kits are often sold on the market - three rods, jumpers and a wire.

It could just be a frame of three rods welded together with steel strips. The end of the rod is usually sharp to make it easier to drive it into the ground.

Rules and requirements of the PUE

At any residential property located within the city limits and beyond, in accordance with the requirements of the PUE, special protection against dangerous voltages of 220/380 Volts is organized. For this purpose, special steel structures called grounding devices (GD) are installed on their territory. Their main purpose is to create conditions that guarantee the protection of people living in the house from electric shock.

In accordance with the PUE, chapter 1.7., part 1, clause 1.7.72, the dimensions of metal blanks are selected taking into account the need to obtain the required resistance to the flow of current into the ground. For various structural elements, these indicators may vary from sample to sample. However, their minimum sizes must comply with the following standards:

the connecting strip between the pins cannot have a standard size of less than 12x4 mm (section 48 mm2);
the pins themselves based on the corners are selected with sides of 4x4 mm;
when using a round reinforcing bar, the cross-section should not be less than 10 mm2;
the metal pipe should have a wall thickness of about 3.5 mm.

Please note: Having the owner of the house with data on the operating characteristics of the electrical circuit, in particular, will protect animals and residents from electric shock.

When arranging it, it is necessary to act in accordance with the provisions of industry standards regarding the operation of the equipment available at the site.

Ready-made grounding kits for a private home

Despite the fact that purchasing and installing a grounding loop yourself is cheaper, home craftsmen are increasingly purchasing ready-made grounding kits for a summer house or private home. Their installation is simpler and therefore faster.

However, buying grounding for a private home, the price of which is higher than the material from which it is made, is not acceptable for everyone. Let's try to summarize the average prices for such kits in Russia as of January 2021:

This is approximately how prices for products are distributed on the Russian market. However, buying ready-made kits is half the battle. You also need to mount the circuit. On average, the cost of installation work on grounding a private house varies from 10,000 to 20,000 rubles. depending on the region.

In general, the cost for the safety of relatives living in the house is not so high. Therefore, it is not worth saving on grounding. If you only purchase the material (angle, tires), the price for grounding a private house can increase significantly and you should not forget about this.

10 Ohm is a popular domestic manufacturer that offers grounding kits for installation at various depths. Installation depth varies from 6 to 30 m, and prices range from 6,000 to 25,000 rubles;
ZandZ are universal grounding electrodes in the form of one or more prefabricated electrodes made of stainless steel. Mounted to a depth of up to 10 m, the price depends on the number of electrodes, installation depth and other parameters. The average cost of an installation kit for 5 m is 23,000 rubles;
Galmar is another popular manufacturer of prefabricated grounding electrodes. Installation is possible to a depth of up to 30 m; such a kit will cost 42,000 rubles;
Elmast – grounding kits from a domestic manufacturer. They are made of stainless steel, supplied unassembled, and can be mounted at different depths. Characterized by a long service life. A distinctive feature of these grounding conductors is their high resistance to aggressive chemical environments and adverse natural influences. The average price for a kit for installation at a 6-meter depth is 9,000 rubles;
Ezetek are relatively inexpensive kits with average performance characteristics. The advantageous advantage of the kit for installation to a depth of 6 m is the price of 6,000 rubles.

There are many other manufacturers offering both ready-made kits for grounding a private home, as well as individual components. You should only trust trusted companies in this matter.

It also makes sense to listen to the recommendations of friends or at least read reviews on thematic forums. If you want to know exactly how to make grounding in private homes, you can find a huge number of video clips and photo instructions on this topic on the Internet.

Device and design of the grounding loop

Classic grounding in a private house or simply a grounding conductor contains in its design such mandatory elements as:

A set of metal pins or rods driven into the ground to a depth of approximately 2-3 meters (they are placed in a pre-dug trench in the shape of a regular triangle).
Flat steel jumpers connecting these pins for welding (photo below).

Triangle ground loop

A special tap made of copper wire or steel strip, necessary to connect the structure to the main grounding bus (it is installed in the distribution cabinet of a private house).

Main grounding bus in the distribution board

The copper grounding conductor goes to the PE bus - the main grounding bus

Additional information: The plane of the triangular contour made of steel strips is usually located at a depth of approximately 50-60 cm.

Having familiarized yourself with the main structural elements of the protective circuit, you can proceed to studying material on how to properly make a grounding circuit in a private house.

Linear grounding diagram

Sometimes, due to the location of the site layout, it is impossible to install a triangular ground loop. In this case, a linear scheme is used, in which the electrodes are arranged in a single line.

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Because the circuit is not closed and does not have the same dispersion quality as a triangular one, the number of vertical electrodes should be brought to 5 pcs., the depth of the electrodes must be no less than the distance between them.

Grounding system calculation

Let's consider the calculation of protective grounding using the example of a linear structure, the pins of which are driven into the ground near the house. When conducting it, you will need to know the following initial indicators:

Dimensions and total number of steel bars.
The distance between them (installation pitch).
Depth of immersion of pins.
Specific soil resistance in the zone of protection.

According to the proposed method for calculating the grounding loop, its main or general task is to find out the required number of rods and determine the parameters of the steel connecting strip.

Example of memory calculation

As an example, we consider the calculation of the resistance of a single vertical rod (photo on the right). To carry it out

Installation diagram of a single vertical ground electrode

the following data is used:

ρ – soil resistivity (in Ohms per meter);

L – total length of the original rod (in meters);

d – its main standard size (diameter) in meters;

T is the distance from the surface of the earth to the middle of the pin.

If we exclude the influence of factors that determine the spread of current in horizontal elements, the resistance for vertical stakes is calculated as follows:

The required number of rods that guarantees the required conductivity value (without taking into account horizontal components) is determined from the following formula: where Rн is the standard spreading indicator standardized by PTEEP.

Taking into account the previously unconsidered horizontal elements, the formula for determining the number of rods takes on the following form:

where ηв is the load factor of the circuit breaker, taking into account the influence of flow currents of different rods on each other.

Additional information: When two rulers of tinder are placed in parallel, their mutual influence is much stronger.

If their arrangement is excessively “dense,” the complex resistance of the circuit breaker increases noticeably. The conductivity value obtained as a result of the proposed calculations is then rounded up.

The considered calculation method can be fully automated if you use an online calculator for calculating grounding resistance, specially designed for these purposes.

How to install a circuit yourself

To make your own ground loop, you will first need to select its type, and then carry out preparatory work based on this design. They include such mandatory procedures as choosing a location for the grounding circuit, selecting the necessary blanks, pins, jumpers, etc., as well as preparing a pit for the grounding loop.

Please note: As an example of manufacturing, we have chosen the simplest triangular design.

Let us consider the stages of the upcoming work in more detail.

Choosing a place for installation

When choosing a site in the local area suitable for arranging a protective contour, we proceed from the following considerations:

it should not be located too far from the house; this will not only save on the connecting bus due to its short length, but also reduce the resistance of the current flow circuit;
the soil at the site where the control panel is installed must be soft enough to allow metal pins to be driven into it;
The quality of the soil on the site also affects the effectiveness of grounding (loams, plastic clay and peat have minimal resistance).

Important! If suitable soil layers are deep, the length of the corner pins will have to be increased to reach the desired soil layers.

We install the structure

First, a small pit about 40-50 cm deep is prepared, shaped like a triangle with dimensions slightly larger than each side of the future grounding structure. All subsequent actions are carried out in the following order:

First of all, vertical grounding conductors are driven into the corners.
Then their ends protruding from the ground, at a distance of approximately 30 cm from the ground surface, are connected to pre-prepared steel jumpers by welding.
After this, a steel strip with a cross-section of at least 48 square meters is welded to one of the peaks (which is located closer to the house). mm and is brought as close as possible to the distribution panel.
At the end of the strip, a steel bolt is welded to which a copper conductor with a cross-section of at least 16 square meters is screwed. mm.
Its other end is inserted into the distribution panel and fixed in it to the main ground bus (GZSh).

Installation of a ground loop in the shape of a triangle

Installation of a linear grounding loop
At the final stage of work, the steel structure, ready for operation, is covered on top with previously discarded earth, which is then compacted well.

You can find detailed instructions for installing a ground loop in the article on our website.

Grounding check

Upon completion of the installation of the ground loop, it is necessary to perform a control check of the design. This check is carried out using quite expensive equipment, but there is a simpler method.

Screw one contact of a 100 W light bulb to one end of the circuit. And the other contact must be attached to the phase.

If the light is quite dim, this means that the contact between the grounding parts is weak, and if the light is bright, then the circuit is fully operational.

There is a third option, when the light does not light up at all, this indicates that the circuit is assembled incorrectly. This simple technology on how to check the grounding of a house will help save money.