People often search for “the new lightning protection standard” and come across conflicting answers. Some sources say every building needs a lightning rod, while others claim it only depends on the building’s height. The current approach is more precise: lightning protection is assessed according to the ČSN EN 62305 series and its risk analysis.
This article explains what the standard covers, when you need a lightning protection system, what the system consists of, and what LPL classes mean. If you are mainly looking for inspection intervals, we cover that in detail in the article Lightning Protection System Inspection – How Often According to ČSN EN 62305.
Quick Answer
The current standard basis for lightning protection is the ČSN EN 62305 series. The need for a lightning protection system is not determined solely by the building’s height. It is decided by a risk analysis according to ČSN EN 62305-2, fire safety requirements, the building’s purpose, the number of occupants, its location in the landscape, its construction, the technology inside, and the potential consequences of a strike.
The lightning protection system is referred to as an LPS (Lightning Protection System). In everyday language, we call it a lightning rod, but the standard works with a complete system: an air-termination system, down conductors, earthing, equipotential bonding, and surge protective devices. The level of protection is expressed by LPL I to IV classes; LPL I is the most stringent.
What ČSN EN 62305 Is and What It Changed
Previously, the old ČSN 34 1390 was used in the Czech Republic. It worked with a simpler approach: building type, height, number of thunderstorm days, and the derived need for a lightning rod. It was clear, but often too crude.
The ČSN EN 62305 series consists of four parts:
- Part 1 – General principles of lightning protection.
- Part 2 – Risk management, i.e., a calculation of whether and at what level you need protection.
- Part 3 – Physical damage to structures and life hazard, i.e., the design of external protection.
- Part 4 – Electrical and electronic systems within structures, i.e., internal protection and overvoltage.
The key change is the risk-based approach. For a new building or a major alteration, the risk analysis is addressed in the project documentation. For an existing building, the certified electrical inspector works from the available documentation, the LPS design, and the actual condition; if the calculation is missing or the building has undergone changes, it may need to be supplemented.
When You Need a Lightning Protection System
A lightning protection system is not automatically mandatory for every building. However, you also cannot safely say you don’t need one just because the house isn’t tall. The decision is based on a specific assessment according to ČSN EN 62305-2 and other documents.
The risk analysis mainly considers:
- Location of the structure – a detached building on a hill has a different risk than a house in a dense urban area.
- Dimensions and shape of the structure – height, roof area, metal superstructures, and technology.
- Construction and materials – combustible constructions increase the consequences of a strike.
- Purpose and occupancy – schools, hospitals, accommodation, assembly spaces, or operations with people inside have higher requirements.
- Risk of fire or explosion – for some operations, the fire safety solution plays a significant role.
- Technology on the roof – photovoltaic (PV) systems, HVAC, antennas, or cooling units change the protection conditions.
- Sensitive electronics inside – server rooms, production controls, security systems, or PV inverters require thorough internal overvoltage protection.
In practice, a calculation for a terraced family house might show that an LPS is not necessary. Conversely, a detached timber building, an industrial hall, an administrative building with a larger number of people, or a building with a PV system on the roof can yield a completely different result. The answer comes from a specific calculation, not a general table.
What a Lightning Protection System Consists Of
According to ČSN EN 62305, lightning protection is divided into external and internal protection. They must work together. An air-termination rod on the roof alone will not protect the electronics in the switchboard; a surge protective device alone will not stop a direct strike to the roof.
External protection (what is visible):
- Air-termination system – captures a direct lightning strike. This can be a mesh system, air-termination rods, ridge conductors, or a combination thereof. It must also protect superstructures on the roof: HVAC units, antennas, PV panels, or roof exits.
- Down conductors – conduct the lightning current from the air-termination system to the ground. They should be mechanically protected, uninterrupted, and routed along the most suitable path according to the system class.
- Earth-termination system – dissipates the lightning current into the ground. It’s not just about one universal earth resistance value; the design, interconnection, measurement, and compliance with the project are important.
Internal protection (what protects the installation and technology):
- Main equipotential bonding and potential equalization – limits dangerous voltage differences inside the building.
- Separation distances – prevents the lightning current from flashing over to metal structures or cables.
- Surge protective devices (SPDs) – protect the electrical installation, electronics, PV inverters, control systems, and appliances from overvoltage during a direct or nearby strike.
Simply put: external protection addresses a direct strike to the structure, while internal protection addresses the consequences of lightning current and overvoltage inside the building.
LPL I–IV Protection Classes
The standard introduces four lightning protection levels – LPL I to IV (Lightning Protection Level). LPL I is the most stringent, LPL IV the least. In documentation, you will also encounter the LPS class, which refers to the design of the lightning protection system. LPL and the LPS class are related, but it’s not advisable to confuse them without reading the project.
What the classes mean in practice:
- LPL I – the highest protection. Typically for buildings where a strike could have exceptionally serious consequences: explosion hazard, critical infrastructure, selected healthcare or technological operations.
- LPL II – a higher level of protection for industrial, commercial, or public buildings with more significant risk.
- LPL III and IV – more common protection levels for less exposed buildings, if the risk analysis shows they need an LPS.
The class affects the specific technical design: spacing of down conductors, mesh size of the air-termination system, rolling sphere radius, separation distances, conductor dimensions, and maintenance requirements. That’s why it’s not enough to say “there’s some kind of lightning rod there.” It must correspond to the design and the protection class.
Lightning Protection and Photovoltaics
A PV system on the roof is a common reason why an old lightning protection system must be reassessed. The panels themselves are not lightning magnets, but they change the roof layout, add conductive structures, cable routes, and technology that can be sensitive to overvoltage.
For PV systems, the main issues addressed are:
- Protection zone of the air-termination system – the panels and their mounting structure should not protrude outside the protected area without further assessment.
- Separation distance – to prevent the lightning current from flashing over from the LPS to the panel structure or cables.
- Bonding and earthing – according to the system design and the method of panel mounting.
- SPDs on both the DC and AC sides – surge protective devices must protect both the DC wiring from the panels and the AC part after the inverter.
If you are interested in PV systems comprehensively, also see the article Photovoltaic System on a Company Roof: Everything You Need to Address and Fire Safety of Rooftop PV Systems.
Inspection and Intervals (Briefly)
A lightning protection system is not a “fit and forget” device. It must be checked regularly because it can be damaged by corrosion, construction work, facade repairs, PV installation, roof replacement, or normal mechanical stress.
In practice, the most common intervals for an LPS are:
- standard buildings – a complete inspection typically once every 4 years,
- critical buildings or higher protection classes – a complete inspection typically once every 2 years,
- visual inspection – once a year.
The exact interval is taken from the documentation, the LPS class, standard requirements, and operating conditions. A complete inspection may only be performed by a certified electrical inspector with a valid certificate for the relevant scope, typically E3A for lightning protection systems. The inspector’s certificate is valid for 5 years.
Details on intervals and the inspection process can be found in a separate article: Lightning Protection System Inspection – How Often According to ČSN EN 62305.
What to Request in Lightning Protection Documentation
When dealing with a new lightning protection system, a reconstruction, or an inspection of an older building, request:
- a risk analysis according to ČSN EN 62305-2,
- the LPS project including the protection class and technical report,
- a drawing of the air-termination system, down conductors, and earthing,
- documentation of the components used and their suitability for the given class,
- earthing measurements and connection to the main equipotential bonding,
- the SPD design and their location in switchboards,
- the initial or latest periodic inspection report,
- records of changes on the roof: PV, HVAC, antennas, roof exits, roofing repairs.
Without documentation, the condition can only be checked to a limited extent. The certified electrical inspector will then often recommend supplementing the risk calculation or the project part to clarify what the system is actually being assessed against.
How SOHE Can Help
At SOHE s.r.o., we specialize in lightning protection system inspections in Brno and nationwide (whole Czech Republic). For older buildings, we check the condition of the air-termination system, down conductors, earthing, and surge protective devices. For buildings with PV systems or new technology on the roof, we check whether the changes have compromised the protection zone and the connection to the LPS.
The output is a clear inspection report that you can use for building management, insurance purposes, building approval, or further project modifications.
Frequently Asked Questions
Is a lightning protection system mandatory for every building? No. The need for a lightning protection system is determined by a risk analysis according to ČSN EN 62305-2 and related project or fire safety requirements. For some buildings, it is deemed necessary; for others, it is not.
What is an LPL class? LPL stands for Lightning Protection Level. There are four classes, I to IV, with I being the most stringent. The technical design of the LPS is derived from the LPL.
Did ČSN EN 62305 replace the old standard? Yes. The old ČSN 34 1390 is no longer the current basis for new designs. The ČSN EN 62305 series introduced a risk-based approach and the assessment of a specific structure.
Do I need a lightning protection system if I have a photovoltaic system on the roof? A PV system is a significant factor for assessing lightning and overvoltage protection, but it does not replace a risk analysis on its own. It is necessary to verify the protection zone, separation distances, bonding, and SPDs on both the DC and AC sides.
Who can perform a lightning protection system inspection? A complete inspection may only be performed by a certified electrical inspector with a valid certificate for the relevant scope, typically E3A for lightning protection. The certificate is valid for 5 years.
Sources for This Article
Text status: 6. 7. 2026, according to currently valid standards and regulations.
- Lightning protection, risk management, LPS design, and LPL protection classes: the ČSN EN 62305 series (parts 1–4). The old ČSN 34 1390 has been replaced.
- Requirements for LPS inspection documents and lightning protection components within designated technical equipment: NV No. 190/2022 Coll..
- Professional competence and certification of a certified electrical inspector: Act No. 250/2021 Coll., NV No. 194/2022 Coll..
- Requirements for lightning protection of buildings from a fire safety perspective: ČSN 73 0810.
Are you wondering if you need a lightning protection system, or do you want to verify compliance with ČSN EN 62305? We will perform a lightning protection system inspection, earthing measurement, and provide a clear report for building management, insurance, and building approval. We are based in Brno and operate nationwide (whole Czech Republic).
- Lightning Protection System Inspections – inspections and measurements according to ČSN EN 62305
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Write to info@sohe.cz or call +420 724 689 762.