City residents care little about lightning protection and grounding; the state has already taken care of them, obliging designers and builders to provide appropriate technical solutions. The issue of lightning protection is especially relevant for owners of dachas and country houses.
To do lightning protection or not to do it is up to the homeowner to decide for himself. However, the construction of grounding and a reliable lightning rod reduces the risk of fire significantly, allowing you to protect wiring, electrical appliances and the lives of the inhabitants of the house.
Lightning hazard
Clouds are water vapor or small ice crystals. They constantly move, rub against warm air streams and become electrified. When the charge difference between them reaches a critical value, a discharge occurs. This is lightning.
When the conductivity between the cloud and the ground is minimal, lightning strikes the ground and all the accumulated charge flows into it. Then you need grounding to absorb the discharge energy.
Lightning strikes the highest point of the structure, passing minimum distance from cloud to object. In essence, a short circuit results, gigantic currents flow, and enormous energy is released.
If there is no lightning protection, then all the lightning energy is absorbed by the building and spreads across conductive structures. The consequences of such a strike are fires, injuries to people, failure of electrical equipment.
Lightning protection absorbs the discharge energy and sends it through the conductor through the ground electrode into the ground, which completely absorbs it. Therefore, lightning rods (lightning rods) and other lightning protection elements are made of conductive materials with high conductivity.
Types of protection
Based on location, lightning protection is divided into external and internal. External protection according to the principle of operation is divided into passive and active. A passive lightning protection device includes three required parts:
- lightning rod;
- down conductor (current conductor);
- ground electrode.
Depending on the structure of the roof, various lightning rods are installed. In active lightning protection, there is an air ionizer at the top of the rod or mast, which creates an additional charge and thus attracts lightning. The range of such protection is much larger than passive protection; sometimes one mast is enough to protect the house and site.
Internal lightning protection
Lightning protection is especially needed inside buildings with a large number of computer equipment. Internal lightning protection is a set of surge protection devices (SPDs).
When a lightning strike strikes an electrical network line, huge short-term overvoltages occur in it. To extinguish them in parallel with the conductors phase and zero, phase and earth, zero and earth, SPDs are installed. These are very fast devices with response times from 100 ns to 5 ns.
The installation diagram and characteristics of the SPD depend on whether there is external lightning protection or not. They differ in design, they are air or gas dischargers, varistors, but the essence is the same.
When a short-term overvoltage occurs, the protected circuit is bypassed and the entire discharge energy is absorbed. But there are devices with a serial connection. The principle of operation is the same; when overvoltages occur, the entire voltage drop occurs on the device.
SPDs are divided into three classes. First class devices are installed in the main distribution board. The SPD reduces the voltage to 4 kV. Devices of the second class are installed in front of the introductory machine of an apartment or building electrical panel and reduce the voltage to 2.5 kV.
Devices of the third class are installed in close proximity to protected devices (computers, servers and similar devices). They provide a reduction of up to 1.5 kV. This voltage reduction is sufficient for most equipment, especially if the duration of the overvoltage is short. It is recommended to entrust this to specialists.
Natural lightning rods
In addition, there are natural lightning rods. Our ancestors, willingly or unwillingly, also had good lightning protection. The tradition of planting birch trees near houses has saved more than one life and more than one house. Birch, despite the fact that it does not conduct electricity very well, is an excellent lightning conductor and at the same time provides grounding.
And all because of the powerful root system, which spreads almost to the surface of the soil. Due to this, the lightning energy, when it hits a tree, spreads over a large area and safely goes into the ground. Pine and spruce are even better as lightning protection, but cannot be compared with birch due to the fragility of the wood.
Design of lightning rods
In general, lightning protection of buildings and structures is a complex of an air terminal, a current conductor and a grounding conductor. Lightning rods are used in the form of a rod, a network and a tensioned cable.
Rod lightning rod
The design of the rod system is simple. The lightning protection pin is connected via a down conductor to metal pins in the ground that provide grounding.
The rods (pins) are made of galvanized or copper-plated steel with a height of half a meter to 5-7 meters. The diameter depends on the height of the rod and the climatic region of location. Copper-plated rod has better electrical conductivity compared to galvanized steel.
Depending on the configuration of the building and its roof, several rods are installed on the roof. They are attached to the ridge, gable, ventilation shafts and other permanent structures.
The zone of influence of lightning protection is a cone with its apex at the tip of the lightning rod. The rods are placed in such a way that their areas of action cover the entire building. For rod lightning rods, the rule of a protective cone with a 90-degree apex is valid for a rod up to 15 m high. The higher the lightning rod, the smaller angle the top of the protective cone.
Network lightning rod
The lightning protection network is a galvanized or copper-plated wire with a diameter of 8-10 mm, covering the entire roof of the building in the form of a network. Typically, lightning protection in the form of a mesh is installed on flat roofs.
The network is formed by wires located perpendicular to each other with a certain pitch. Using holders, the wires are connected to each other and attached to the roof. Sometimes, instead of wire, a steel strip is used.
The wire or strip must be connected to ground. Welding is used for connection, but it can be done with special clamps. Clamps for connecting grounding electrodes to conductors are often included if you purchase all the parts in a specialized store.
Cable lightning rod
Cable lightning rods are a steel or aluminum cable stretched between two masts. The masts are connected to down conductors, which in turn are connected to grounding. Imagine that the cable is the ridge of a gable roof.
Then the area under this virtual roof will be protected from lightning strikes. Thus, by stringing several cables over the roof of the house and the surrounding area, you can provide reliable lightning protection.
Current conductors are galvanized or copper-plated steel wires with a diameter of 10 mm; steel strips with a cross-section of 40x4 mm coated with zinc or copper are often used. They connect lightning rods to the grounding conductor.
The lightning protection kit also includes holders for lightning rods and conductors. They are made from steel and plastic materials, have a variety of designs.
Location of ground electrodes
Grounding of lightning rods, in fact simple case, consists of three three-meter metal rods driven into the ground at a distance of 5 meters from each other. The grounding pins are connected to each other by a steel strip located at a depth of 50-70 cm underground.
The connection is made by welding, which is then covered with an anti-corrosion coating. At the locations of the pins, the rods must extend to the surface so that the conductors can be connected.
Grounding must be located at a distance of at least 1 meter from the structure and more than 5 meters from the porch, paths and other places where people constantly walk. This is necessary so that a person does not come under the step voltage generated when the lightning charge spreads from the ground electrode along the ground.
If the building has a massive reinforced concrete foundation, then it is recommended to locate the lightning protection grounding away from it and install internal lightning protection in the form of lightning arresters to protect the equipment. This is necessary because part of the charge is thrown onto the foundation and all elements that have good contact with it, primarily equipment housings and utilities.
Resistance requirements
The grounding circuit of the house must be connected to the grounding of the lightning protection through steel conductors that are welded together. The grounding resistance should be as low as possible. The standard value is 10 Ohms for soils with a resistivity of up to 500 Ohms, but for larger values, a different resistance is allowed, which is calculated using the formula:
Rз is the grounding resistance, and ρ is the soil resistivity.
To achieve the standard value, the soil is sometimes replaced. A trench is dug, new soil with the appropriate characteristics is laid, and then grounding is installed. Another option is to add chemicals.
After installing the lightning protection grounding, it is necessary to regularly measure its resistance. If it goes beyond the standard value, you will have to add a pin or replace it with a new one.
In this case, you need to pay close attention to the connections between the elements of the device. The use of stainless materials will significantly increase the service life of the ground electrode.
Grounding- these are connections of a part of the electrical network or equipment to a grounding device. The grounding device is a ground electrode - a conductive part in contact with the ground. The ground electrode can be in the form of metal elements of complex shape.
The quality of grounding is determined by the resistance value of the grounding device, which can be reduced by increasing the area of the grounding conductors or the conductivity of the medium. The electrical resistance of the grounding device is provided for in the design in accordance with the requirements of the Electrical Installation Rules.
Such a grounding loop is installed in a development-free area of the site. The following are subject to grounding:
- household electrical appliances with a unit power exceeding 1.3 kW;
- metal bodies of bathtubs and shower trays (they must be connected by metal conductors to water supply pipes);
- metal casings of power supply units, built-in or installed in dropped ceilings made using metal;
- metal cases household air conditioners air.
Grounding conductors are installed before electrical installation work begins. The connection of foundation reinforcement with wall reinforcement must be carried out by a construction organization. Grounding conductors are connected to pipelines using welding or a clamp. If it is impossible to use natural grounding conductors, artificial grounding conductors are used. These include a grounding loop, which is created both for grounding electrical appliances and for lightning protection.
Lightning protection is a system of devices that ensures the safety of a building during electrical discharges in the atmosphere. Its main task is to change the trajectory of lightning discharges and dampen its energy. Lightning protection includes:
- lightning rod - a device that receives a lightning discharge;
- down conductor—electric discharge distribution elements;
- ground electrode - a device for extinguishing an electrical discharge.
There are several lightning protection schemes. Scheme based on lightning rod includes a metal rod connected by cables to a ground electrode. Lightning rod based on a “spatial grid” installed on the roof of the house. It distributes and extinguishes the discharge in the event of a direct hit. Scheme based on tension systems similar to the lightning rod circuit, but the conductors are stretched along the perimeter of the protected area.
All of the above structures are made of steel rods, ropes or steel mesh (with a diameter of at least 6 mm). The elements in the nodes are connected by welding. The most common design is rod lightning rods because they are the simplest to manufacture and ensure system reliability.
Lightning rods based on tension systems are used when constructing roofs of complex shapes. The spatial grid requires more materials and is more difficult to install. This type of lightning rod is advisable if the roof of the house is higher than other objects located within a radius of 50 m.
Absolutely any suburban a private house must have a grounding circuit to protect people from electric shock. The greatest danger is posed by such devices - where electricity and water are combined. At your dacha, this is the boiler from which you take a shower, washing machine, kettle, pump, septic tank, Dishwasher: you use all of these every day and even You don’t think about how dangerous it is without grounding. If 380 volts are supplied to your house, then re-grounding is simply a must!
Ground loop country house we do it as follows: first, a trench one bayonet wide is dug in the form of an equilateral triangle to a depth of 0.5 m. The length of the sides of the triangle is 1.5 meters. Along the edges of the triangle, vertical grounding conductors made of steel angle 50x50x5 are driven to a depth of more than two meters. The structure is welded with horizontal grounding conductors in the form of a 40x4 steel strip, which is removed from the contour and fixed to the facade of the building. At the edge of the strip, an M8 bolt is welded through which, using a special cable connecting lug, using the crimping method, a transition is made to copper wire PV-1 (PV-3 or PUGV) with a cross-section of at least 10 square millimeters. All connections are made only by welding and treated with mastic to prevent corrosion. This grounding will serve you for decades. Ultimately, the grounding wire is connected to the main grounding bus (GZSh). Then comes the next crucial moment - the work of connecting the grounding in the panel. It is necessary to select the correct grounding system for the electrical installation. The following systems are currently used: TN (with subsystems TN-C, TN-S, TN-C-S) and TT. Contact us and we will professionally select the most suitable grounding system for your home. 
If your home is at risk of being struck by lightning, then we can protect it too. Nowadays, two lightning protection systems are used - active and passive. The second one is most often used. We install lightning protection systems on any type of roof: metal tiles, ondulin, slate, tiles, soft roof and iron. We also carry out installation ready-made kits lightning protection from the world's leading manufacturers.
In a passive lightning protection system, a special lightning rod is mounted on the roof ridge. The descent from the roof along the facade is carried out with a galvanized steel conductor on special remote brackets. Through the down conductor, lightning enters the grounding circuit and the charge is extinguished in the ground at a depth. IN active system different manufacturers use lightning protection various principles work: for example, active lightning rods with electronic devices, which emit a high-voltage pulse of a certain frequency and amplitude directed towards the lightning. Having captured a lightning discharge, it is also sent to the ground through a down conductor
We also strongly recommend installing a surge protection device (SPD) to protect your electrical wiring and expensive equipment from lightning entering the power grid or interference resulting from this natural phenomenon. 
Lightning has always been considered an uncontrollable element, one of the most terrible and dangerous natural phenomena. Despite the fact that direct damage to objects is rare, the severe consequences of such attacks force us to look for effective ways protection. If there is a power line or a high tower with a lightning rod near the house, in this case we can assume that the danger has been significantly reduced. If Vacation home is a lonely building, in addition located on a hill and near a reservoir, then you should not take risks, but carry out such measures as lightning protection and grounding.
Their arrangement should be planned at the design stage, then upon completion of construction the object itself and its protection will form a single whole.
Grounding and lightning protection in a private house
Lightning strikes can have serious negative consequences. Most often, the roof and supporting structures are damaged, external and internal power supplies fail, and fires occur. The most severe of them are considered to be injuries of varying degrees of severity received by people and animals. All this can be avoided by installing lightning protection and grounding, which are mandatory for installation in private homes. They are created in individually, in accordance with the region, climate zone, type of housing and other factors.
To determine the scope of work, preliminary calculations are performed. All this is reflected in the documentation, including the as-built diagram, calculation of the height of the lightning rod, estimate for construction and installation work and a list of resources expended. If the design was carried out by a third-party organization, upon completion of the work, tests and measurements are carried out to confirm the compliance of the system with the design and estimate documentation. This procedure ends with an acceptance certificate, which reflects the results of the activities carried out.
Lightning protection is divided into two main types:
- Passive includes traditional elements - lightning rod, down conductor, etc. After a lightning strike, the electric charge goes into the ground along this entire chain. Such systems are not suitable for metal roofs, which is the only serious limitation.
- Active lightning protection works on the basis of pre-prepared ionized air, which intercepts lightning strikes. This system has a large range, covering not only the house itself, but also other objects located nearby.
The design of a typical lightning protection and grounding system consists of several main elements:
- Lightning rod. Its height always exceeds the highest part of the building by 2-3 meters. It should not be located even higher, since lightning will strike much more often. It is made in the form of a metal pin or cable stretched over an object.
- Down conductor. Connects the lightning rod and the grounding system. It is made of metal reinforcement with a cross-section of at least 6 mm2, ensuring a free discharge path into the ground.
- Ground electrode. It is manufactured in the same way as a conventional grounding loop. It consists of two parts - underground and above ground.
Construction of grounding and lightning protection networks
Having examined in general terms the importance of lightning protection for a private home, we should dwell in more detail on individual elements of the system and installation features. First of all, even before starting work on grounding, it is necessary to decide whether protection will be provided, including from lightning. The point is that in order to fulfill your normal functions Any configuration of the ground electrode can be used, and the grounding and lightning protection device requires the use of a strictly defined type of structure.
In this case, at least two vertical electrodes 3 meters long must be installed. They are combined using a common horizontal electrode. The distance between the pins must be at least 5 meters. Such grounding is mounted along one wall, connecting down conductors in the ground, lowered from the roof. If several down conductors are used at once, the lightning protection grounding loop is laid at a distance of one meter from the walls and located at a depth of 50-70 cm. The down conductor itself is connected to a vertical electrode 3 meters long.
External and internal lightning protection
After grounding, you can proceed to the direct installation of lightning protection, which is divided into two parts - external and internal. External protection, consisting of a lightning rod and a down conductor, has already been considered, so it is worth dwelling in more detail on the internal protection of a building from lightning.
Its main task is to protect equipment and household appliances installed inside the building. They can also be seriously injured by lightning. Therefore, protective measures are carried out using an SPD device for protection against. It consists of nonlinear elements in the amount of one or several units.
The internal components of the protective device can be connected not only in certain combinations, but also different ways: phase-to-earth, phase-to-phase, phase-to-zero and zero-to-earth. According to the standards defined in the PUE, all SPDs used to protect the electrical networks of private houses must be installed only behind the input circuit breaker.
Options for installing internal protective devices depend on whether the house has or does not have external lightning protection. If available, a classic protective cascade is installed, consisting of devices of classes 1, 2, 3, located in series. A class 1 SPD is installed at the input and limits the current in the event of a direct lightning strike. A device of the 2nd class can also be installed inside the input or distribution panel in a large building, with a distance between the panels of more than 10 m. The second class protects against induced voltages and limits the current within 2500 V. If there are sensitive electronics in the house, an SPD 3- is additionally installed. class with a voltage limitation of 1500 V.
In the absence of external lightning protection, a class 1 SPD is no longer required, since there will no longer be a direct lightning strike. Rest protective devices installed according to the previous scheme with external protection.
Dear readers! The instructions are voluminous, so for your convenience we have made navigation through its sections (see below). If you have questions about the selection, calculations and design of grounding and lightning protection systems, please write or call, they will be happy to help!
Introduction - about the role of grounding in a private house
The house has just been built or purchased - in front of you is exactly the cherished home that you recently saw in a sketch or photograph in an ad. Or maybe you have been living in your own home for several years now, and every corner in it has become home. Having your own personal home is wonderful, but along with the feeling of freedom, you also get a number of responsibilities. And now we will not talk about household chores, we will talk about such a necessity as grounding for a private home. Any private home includes the following systems: electrical network, water supply and sewerage, gas or electrical system heating Additionally, a security and alarm system, ventilation, a “smart home” system, etc. are installed. Thanks to these elements, a private home becomes a comfortable living environment for a modern person. But it really comes to life thanks to the electrical energy that powers the equipment of all the above systems.
The need for grounding
Unfortunately, electricity also has a downside. All equipment has a service life, each device has a certain reliability built into it, so they will not work forever. In addition, during the design or installation of the house itself, electrical, communications or equipment, errors can also be made that can affect electrical safety. For these reasons, part of the electrical network may be damaged. The nature of accidents can be different: short circuits may occur, which are turned off by automatic switches, or breakdowns may occur on the housing. The difficulty is that the breakdown problem is hidden character. The wiring was damaged, so the body of the electric stove was energized. If grounding measures are incorrect, the damage will not manifest itself until a person touches the stove and receives an electric shock. Electrocution will occur due to the fact that the current seeks a path into the ground, and the only suitable conductor is the human body. This cannot be allowed.
Such damage poses the greatest threat to human safety, because in order to detect it early, and therefore to protect against it, it is imperative to have grounding. This article discusses what actions need to be taken to organize grounding for a private home or cottage.
The need to install grounding in a private house is determined by the grounding system, i.e. the neutral mode of the power source and the method of laying the neutral protective (PE) and neutral working (N) conductors. The type of power supply network - overhead or cable - may also be important. Design differences Grounding systems allow us to distinguish three options for power supply to a private home:
The main potential equalization system (BPES) combines all large current-carrying parts of the building, which normally do not have electrical potential, into a single circuit with the main grounding bus. Let's consider a graphic example of implementing a control system in an electrical installation of a residential building.
First, let's look at the most progressive approach to electrical power at home - the TN-S system. In this system, the PE and N conductors are separated throughout, and the consumer does not need to install grounding. You just need to connect the PE conductor to the main grounding bus, and then connect the grounding conductors to electrical appliances from it. Such a system is implemented both by cable and overhead line; in the case of the latter, VLI (insulated overhead line) is laid using self-supporting wires (SIP).
But not everyone has such happiness because the old overhead transmission lines use the old grounding system - TN-C. What is its peculiarity? In this case, PE and N along the entire length of the line are laid with one conductor, which combines the functions of both the neutral protective and neutral working conductors - the so-called PEN conductor. If previously it was allowed to use such a system, then with the introduction of the PUE 7th edition in 2002, namely clause 1.7.80, the use of RCDs in the TN-C system was prohibited. Without the use of an RCD, there can be no talk of any electrical safety. It is the RCD that turns off the power if the insulation is damaged as soon as it occurs, and not at the moment when a person touches the emergency device. To meet all necessary requirements, the TN-C system must be upgraded to TN-C-S.
In the TN-C-S system, a PEN conductor is also laid along the line. But, now, paragraph 1.7.102 of the PUE 7th ed. says that at the overhead line inputs to electrical installations, repeated grounding of the PEN conductor must be performed. They are carried out, as a rule, at an electrical pole from which the input is made. When re-grounding, the PEN conductor is divided into separate PE and N, which are brought into the house. The re-grounding norm is contained in clause 1.7.103 of the PUE 7th ed. and is 30 Ohm, or 10 Ohm (if there is a gas boiler in the house). If grounding at the pole is not completed, you must contact Energosbyt, whose department is responsible for the electric pole, distribution board and entry into the consumer’s house, and point out the violation that must be corrected. If the distribution panel is located in the house, the PEN separation should be done in this panel and the re-grounding should be done near the house.
In this form, TN-C-S is successfully operated, but with some reservations:
- if the condition of the overhead line causes serious concern: the old wires are not in better condition, which creates a risk of breakage or burnout of the PEN conductor. This is fraught with the fact that there will be increased voltage on the grounded housings of electrical appliances, because the current path into the line through the working zero will be interrupted, and the current will return from the bus on which the separation was performed through the neutral protective conductor to the device body;
- If there are no repeated groundings on the line, then there is a danger that the fault current will flow into a single re-grounding, which will also lead to an increase in the voltage on the frame.
In both cases, electrical safety leaves much to be desired. The solution to these problems is the TT system.
In the TT system, the PEN conductor of the line is used as a working zero, and individual grounding is performed separately, which can be installed near the house. Clause 1.7.59 PUE 7th ed. stipulates the case when it is impossible to ensure electrical safety and allows the use of the TT system. An RCD must be installed, and its correct work must be provided by the condition Ra*Ia<=50 В (где Iа - ток срабатывания защитного устройства; Ra - суммарное сопротивление заземлителя). «Инструкция по устройству защитного заземления» 1.03-08 уточняет, что для соблюдения этого условия сопротивление заземляющего устройства должно быть не более 30 Ом, а в грунтах с высоким удельным сопротивлением - не более 300 Ом.
How to ground a house?
The purpose of grounding for a private home is to obtain the required grounding resistance. For this purpose, vertical and horizontal electrodes are used, which together must ensure the necessary spreading of current. Vertical grounding electrodes are suitable for installation in soft soil, while their burial in rocky soil is very difficult. In such soil, horizontal electrodes are suitable.
Protective grounding and lightning protection grounding are carried out in common; one ground electrode will be universal and serve both purposes, this is stated in paragraph 1.7.55 of the PUE 7th ed. Therefore, it will be useful to learn how to unify lightning protection and grounding. To clearly see the installation process of these systems, the description of the grounding process for a private house will be divided into stages.
A separate point should be made about protective grounding in the TN-S system. The starting point for grounding installation will be the type of power system. The differences in power systems were discussed in the previous paragraph, so we know that for the TN-S system there is no need to install grounding, the neutral protective (grounding) conductor comes from the line - you just need to connect it to the main grounding bus, and the house will be grounded. But one cannot say that a house does not need lightning protection. This only means that we, without paying attention to stages 1 and 2, can immediately move on to stages 3-5, see below
TN-C and TT systems always require grounding, so let's move on to the most important thing.
Protective grounding is installed at a pole or at the wall of the house, depending on where the PEN conductor is separated. It is advisable to locate the ground electrode in close proximity to the main ground bus. The only difference between TN-C and TT is that in TN-C the grounding point is tied to the PEN separation point. The grounding resistance in both cases should be no more than 30 Ohms in soil with a resistivity of 100 Ohm*m, for example loam, and 300 Ohms in soil with a resistivity of more than 1000 Ohm*m. The values are the same, although we rely on different standards: for the TN-C system 1.7.103 PUE 7th edition, and for the TT system - on paragraph 1.7.59 of the PUE and 3.4.8. Instructions I 1.03-08. Since there are no differences in the necessary measures, we will consider general solutions for these two systems.
For grounding, it is enough to drive a six-meter vertical electrode.
(click to enlarge)
This grounding turns out to be very compact; it can be installed even in the basement; no regulatory documents contradict this. The necessary actions for grounding are described for soft soil with a resistivity of 100 Ohm*m. If the soil has a higher resistance, additional calculations are required, contact ZANDZ.ru technical specialists for help in calculations and selection of materials.
If a gas boiler is installed in the house, then the gas service may require grounding with a resistance of no more than 10 Ohms, guided by clause 1.7.103 of the PUE 7th ed. This requirement must be reflected in the gasification project.
Then, to achieve the standard, it is necessary to install a 15-meter vertical grounding conductor, which is installed at one point.
(click to enlarge)
It can also be installed at several points, for example, at two or three, then connected with a horizontal electrode in the form of a strip along the wall of the house at a distance of 1 m and at a depth of 0.5-0.7 m. Installation of the ground electrode at several points will also serve the purpose of lightning protection To understand how, let’s move on to its consideration.
Before installing grounding, you need to immediately decide whether the house will be protected from lightning. So, if the configuration of the ground electrode for protective grounding can be any, then the grounding for lightning protection must be of a certain type. At least 2 vertical electrodes 3 meters long are installed, united by a horizontal electrode of such length that there is at least 5 meters between the pins. This requirement is contained in paragraph 2.26 of RD 34.21.122-87. Such grounding should be installed along one of the walls of the house; it will be a kind of connection in the ground of two down conductors lowered from the roof. If there are several down conductors, the correct solution is to lay a grounding loop for the house at a distance of 1 m from the walls at a depth of 0.5-0.7 m, and at the junction with the down conductor, install a vertical electrode 3 m long.
(click to enlarge)
Now it’s time to find out how to make lightning protection for a private home. It consists of two parts: external and internal.
Carried out in accordance with SO 153-34.21.122-2003 “Instructions for the installation of lightning protection of buildings, structures and industrial communications” (hereinafter referred to as SO) and RD 34.21.122-87 “Instructions for the installation of lightning protection of buildings and structures” (hereinafter referred to as RD).
Buildings are protected from lightning strikes using lightning rods. A lightning rod is a device that rises above the protected object, through which the lightning current, bypassing the protected object, is discharged into the ground. It consists of a lightning rod that directly absorbs the lightning discharge, a down conductor and a grounding conductor.
Lightning rods are installed on the roof in such a way that a protection reliability of more than 0.9 CO is ensured, i.e. the probability of a breakthrough through the lightning rod system should be no more than 10%. For more information about what reliability of protection is, read the article “Lightning protection of a private home”. As a rule, they are installed along the edges of the roof ridge if the roof is gable. When the roof is mansard, hipped or even more complex in shape, lightning rods can be attached to chimneys.
All lightning rods are connected to each other by down conductors; the down conductors are connected to a grounding device that we already have.
(click to enlarge)
Installing all these elements will protect the house from lightning, or rather from the danger posed by its direct strike.
Protecting your home from surge voltages is done using an SPD. For their installation, grounding is necessary, because the current is diverted into the ground using neutral protective conductors connected to the contacts of these devices. Installation options depend on the presence or absence of external lightning protection.
- There is external lightning protection
In this case, a classic protective cascade is installed from devices of classes 1, 2 and 3 arranged in series. A class 1 surge protector is mounted at the input and limits the direct lightning strike current. A class 2 surge protector is installed either in the input panel or in the distribution panel, if the house is large and the distance between the panels is more than 10 m. It is designed to protect against induced overvoltages, it limits them to a level of 2500 V. If the house has sensitive electronics, then It is advisable to install a class 3 surge protector that limits overvoltages to a level of 1500 V; most devices can withstand this voltage. A class 3 surge protector is installed directly next to such devices. - There is no external lightning protection
A direct lightning strike into a house is not taken into account, so there is no need for a class 1 SPD. The remaining SPDs are installed in the same way as described in paragraph 1. The choice of SPD also depends on the grounding system; to be sure of the correct choice, contact ZANDZ.ru technical specialists for help.
The figure shows a house with installed protective grounding, an external lightning protection system and a combined SPD of class 1+2+3, intended for installation in a TT system.
Comprehensive home protection: protective grounding, external lightning protection system and
combined SPD class 1+2+3, intended for installation in a TT system
(click to enlarge)
Enlarged image of a switchboard with an installed surge protector for a home
(click to enlarge)
| No. | Rice | vendor code | Product | Qty |
| Lightning protection system | ||||
| 1 | ZANDZ Lightning rod-mast vertical 4 m (stainless steel) | 2 | ||
| 2 |  | GALMAR Holder for lightning rod - mast ZZ-201-004 to the chimney (stainless steel) | 2 | |
| 3 |  | GALMAR Clamp for lightning rod - mast GL-21105G for down conductors (stainless steel) | 2 | |
| 4 |  | GALMAR Copper-plated steel wire (D8 mm; coil 50 meters) | 1 | |
| 5 | GALMAR Copper-plated steel wire (D8 mm; coil 10 meters) | 1 | ||
| 6 |  | GALMAR Downpipe clamp for down conductor (tinned copper + tinned brass) | 18 | |
| 7 |  | GALMAR Universal roof clamp for down conductor (height up to 15 mm; galvanized steel with painting) | 38 | |
| 8 |  | GALMAR Facade/wall clamp for down conductor with raised surface (height 15 mm; galvanized steel, painted) | 5 | |
| 9 |  | |||
