Lightning protection and grounding design

Why is an error in a lightning protection project not a technical flaw, but a threat to the facility and people?

A lightning strike to a building without a designed protection system is not only the destruction of the point of direct impact. This is a current pulse of tens and hundreds of kiloamperes, which spreads through metal structures, cables and pipelines, destroying equipment, starting a fire and creating a potential difference that is dangerous to human life. Secondary manifestations of a lightning discharge - overvoltage in power and information networks - disable servers, dispatch systems, frequency converters and other sensitive equipment even when lightning strikes hundreds of meters from the facility.

AYU-Project designs lightning protection and grounding systems for facilities of any purpose and complexity: residential and public buildings, industrial enterprises, oil and gas and telecommunications infrastructure. We develop a complete set of design documentation and working documentation - from calculating the lightning protection category and lightning rod protection zones to designing a grounding device (GD) circuit, a potential equalization system (PES) and surge protection devices (SPDs).

What does a comprehensive building lightning protection system include?

Complete protection of an object from lightning discharges consists of two interconnected subsystems - external and internal lightning protection, which complement and reinforce each other. The absence or poor design of any of them reduces the efficiency of the entire system.

External lightning protection intercepts the discharge and safely discharges the lightning pulse current into the ground. Includes three interrelated elements:

• Lightning protection system - intercepts the discharge channel before it reaches the protected structure. It is sold in the form of rod lightning rods, cable systems or lightning protection meshes on the roof; the choice of type and configuration is determined by the shape of the building, roofing material and calculation of the protection zone;
• Down conductors - conductors along which the lightning current from the lightning rod moves to the grounding device; laid on external walls with standardized spacing and connections;
• Lightning protection grounding device - a system of horizontal and vertical electrodes in the ground, ensuring the spread of pulsed current with a standardized resistance.

Internal lightning protection neutralizes the effects of lightning current that has already hit an object or induced in its network. Includes:

• Potential equalization system (equipotential bonding system) - connection of all metal structures, pipelines, cable screens and neutrals of electrical equipment to the main grounding bus (GZSh), which eliminates dangerous potential differences between the conductive parts of the object;
• Surge protection devices (SPDs) - multi-stage protection of power and extra-low-voltage networks from overvoltage pulses; are installed in several levels (class I, II, III) with coordinated parameters.

How is the category of lightning protection determined and what does it mean?

The lightning protection category is one of the first parameters that is determined during the development of DD: the required level of protection reliability and the composition of the technical solutions used depend on it.

The document valid in Russia is SO 153-34.21.122-2003 “Instructions for the installation of lightning protection of buildings, structures and industrial communications” - divides objects into ordinary (residential, administrative, commercial, industrial buildings with a height of up to 60 m) and special (explosive, chemical, radiation facilities, as well as buildings with a height of more than 60 m). For ordinary objects, four levels of protection are provided (I-IV) with reliability from 0,80 to 0,98, for special ones - from 0,90 to 0,999.

RD 34.21.122-87 also remains applicable, which classifies buildings into categories I, II, III depending on the type of facility and the geographic intensity of thunderstorm activity. For explosive objects of category I (oil and gas industry, powder warehouses), the requirements for lightning protection are maximum. The choice of settlement document and assessment method is agreed upon with the examination body at the DD stage.

How is the grounding device calculated?

Calculation of the grounding device is a key engineering procedure, the result of which is a circuit of horizontal and vertical electrodes that provides standardized resistance to current flow over the entire range of temperatures and soil humidity. Lightning protection resistance grounding system SO 153-34.21.122-2003 should be no more than 10 Ohm; with a combined charger with an electrical installation, as a rule, it is accepted according to strict conditions PUE (7th edition) - no more than 4 ohms.

The grounding system calculation performed by AYU-Project includes:

• engineering-geological study of the site - analysis of data on the composition and electrical resistivity of the soil (ρ, Ohm m) taking into account seasonal coefficients; for high-resistivity soils (ρ > 500 Ohm m), special technical solutions are being developed - deep-immersion grounding electrodes, electrolytic electrodes or soil impregnation;
• calculation of configuration grounding system - perimeter horizontal contour made of steel strip or copper-plated strip with vertical rod electrodes; for industrial facilities - deep mesh grounding devices under the foundations of buildings;
• checking the sufficiency of natural grounding conductors - reinforcement of reinforced concrete foundations, metal piles, underground cables with a metal sheath;
• calculation of down conductors - sections, materials (steel, copper, aluminum), methods of laying and connections;
• calculation of lightning rod protection zones using the rolling sphere method or a simplified method - with checking the overlap of the entire protected surface of the object.

What is SPD and when is it required in a project?

SPD (surge protection device) is a device that limits the amplitude of overvoltages in power and low-current networks that occur during lightning discharges, switching and other impulse impacts. The presence of SPD in the project is a mandatory requirement SO 153-34.21.122-2003 for facilities with electronic equipment - server rooms, data centers, medical institutions, industrial enterprises with automated process control systems, buildings with security systems.

The design of SPD is carried out according to the zonal principle: the entire protected space of the facility is divided into lightning protection zones (LPZ 0, LPZ 1, LPZ 2), on the boundaries of which SPD of the corresponding class are installed:

• Class I (type 1) - at the entrance to the building (boundary LPZ 0/LPZ 1); diverts the main share of lightning current to the ground; mandatory in the presence of overhead power lines or in a facility with direct lightning rods;
• Class II (type 2) - in main and floor distribution boards (boundary LPZ 1/LPZ 2); limits residual voltage to a level that is safe for equipment;
• Class III (type 3) - directly at sensitive equipment (final stage of coordination).

Coordination of SPDs is the selection of a combination of characteristics of devices of different stages so that each next level gets what the previous stage did not extinguish. Incorrect coordination means that SPDs stand but do not protect.

What is included in the design documentation and working documentation on lightning protection and grounding?

Documentation on lightning protection and grounding is developed in accordance with Government Decree of the Russian Federation No. 87 dated 16.02.2008 No. 87 (as amended on 21.10.2025) “On the composition of sections of design documentation and requirements for their content” and requirements GOST R 21.614, SO 153-34.21.122-2003 And GOST R 58698-2019.

Design documentation stage includes: an explanatory note defining the category (level) of lightning protection, calculation of lightning rod protection zones, calculation and justification of the grounding system configuration; schematic diagrams of external lightning protection and equipotential bonding system; description of measures taken to protect against secondary manifestations of lightning, including SPD.

Working Documentation Stage (WD) contains: a roof plan with a lightning protection system and a diagram for laying down conductors; foundation plan (or excavation plan) with the location and dimensions of the charger circuit, vertical electrodes and connecting conductors; diagram of the main ground bus (GZB) and connection of the MUP conductors to it; calculation and layout of SPDs in switchboards; details of connection units for lightning rods, down conductors and chargers; cable log of grounding and equalizing conductors; specifications of equipment and materials.

Regulatory basis for designing lightning protection and grounding

Lightning protection and grounding of buildings are designed in accordance with a set of regulatory and technical documents:

• SO 153-34.21.122-2003 - the main current document on lightning protection of ordinary and special objects, harmonized with the IEC 62305 series; defines protection levels, zone calculation methods, requirements for potential equalization systems and SPD;
• WD 34.21.122-87 - instructions for the installation of lightning protection of buildings and structures in categories I-III; continues to be used for a number of objects;
• GOST P IEC 62305 (parts 1-4) - an international series of lightning protection standards in Russian adaptation;
• GOST R 58698-2019 “Lightning protection. Lightning protection of buildings and structures” is a current Russian standard;
• GOST R 59789-2021 - protection of structures, buildings and structures from lightning;
• PUE (7th edition), Chapter 1.7 - grounding and protective electrical safety measures; requirements for grounding systems TN-S, TN-C-S, TT, IT and conductors of the control system;
• GOST R 50571.5.54-2013 - selection and installation of grounding devices and protective conductors;
• Government Decree of the Russian Federation No. 87 dated 16.02.2008 No. 87 (as amended on 21.10.2025) “On the composition of sections of project documentation and requirements for their content” - regarding the composition of design documentation.

For which facilities do we design lightning protection and grounding?

AYU-Project designs lightning protection and grounding systems for the full range of B2B facilities: from a standard apartment building to a large industrial facility with increased reliability requirements.

Priority directions:

• Industrial enterprises - lightning protection categories I-II for facilities with flammable and explosive environments; comprehensive design grounding system taking into account industrial frequency currents and lightning pulse currents;
• Residential and public buildings - lightning protection grids and lightning rods on the roof, equipotential bonding system in thermal units and electrical panels, SPD in main switchboards;
• Communication facilities, data centers, telecommunications infrastructure - multi-stage systems SPD for power and signal circuits, low-resistance grounding system with controlled resistance;
• Oil and gas industry and pipeline infrastructure facilities - special lightning protection for objects of category I, including protection against side impacts and protection against electromagnetic interference;
• Sports and transport facilities - cable lightning protection systems for open stadiums, protection of the upper and side zones of high-rise buildings;
• High-rise buildings (more than 60 m) - special lightning protection taking into account the probability of lateral lightning strikes starting from a height of 60 m.

Why do construction companies trust AYU-Project to design lightning protection?

Lightning protection is a section that is often perceived as a formality: “install a lightning rod and draw a contour.” It is this relationship that generates objects with grounding system mounted according to a scheme that is in no way related to the calculation, with equipotential bonding system missing in the thermal unit and with SPD installed in a single class instead of three. All this is clarified either during an examination or after the first serious thunderstorm.

Calculation, not rule-making. Each project begins with an engineering calculation: soil resistance, lightning currents, protection zones, SPD coordination - and not with the selection of standard solutions by analogy.

Experience in high-profile facilities. Implemented projects for Russian Railways, PJSC Rosseti Siberia, NTEK and a number of federal infrastructure facilities mean that lightning protection for us is not an auxiliary section, but an independent engineering discipline.

Integration into a single solution. Lightning protection and grounding are designed in inextricable connection with power equipment, power supply systems and extra-low-voltage systems - without contradictions in design solutions and cable logs.

Fixed Schedule and Price are fixed in the contract and are not revised.

Cost and procedure for ordering lightning protection design

The cost of developing design documentation and working documentation is determined individually: the type of object and its lightning protection category, roof area and building height, characteristics of soil conditions, composition of SPD systems, presence of explosive zones, list of stages being developed. Approximate calculation - through the online calculator on the website.

To receive an accurate commercial proposal, leave a request: indicate the type and purpose of the object, number of floors, available initial data - general plan, architectural solutions, soil data. Attach existing materials. The initial consultation is free, and we work across Russia remotely.