Glossary · Lightning, earthing, fire safety
Lightning risk assessment
The DSTU EN 62305-2:2022 calculation deciding whether a building with PV needs external lightning protection; there is no "PV means LPS" rule.
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Definition
Whether a building needs external lightning protection (LPS) is decided in Ukrainian norms by a risk assessment. DBN V.2.5-23:2025 (cl. 4.5) refers lightning protection to DSTU EN 62305-1:2012 … DSTU EN 62305-4:2012, DBN V.1.1-7:2016 (cl. 6.45) to the current normative documents, and NAPB A.01.001-2014 (section IV, ch. 1, cl. 1.21) to the level set by the design documents or the system maker’s recommendations. The assessment method is DSTU EN 62305-2:2022.
The norms have no rule saying "PV on the roof means LPS is mandatory". The panels change the inputs of the assessment (height, area, electrical lines, the value of equipment), but the result depends on the building and its surroundings as a whole.
One input is the ground flash density NG, flashes per km² per year. For Kyiv, from the UkrHMC thunderstorm days of 2015–2023, it is about 2.0; for Ivano-Frankivsk 4.2, for Kherson 2.6. So the risk in the west of the country is noticeably higher than in the centre.
If the building already has an LPS, the PV plant must work with it: keep the separation distance or be bonded to it, with suitable SPDs. If there is no LPS and the assessment does not require one, the frame is still earthed together with the building.
What an owner should do. For a detached house without an LPS, the decision follows the risk assessment carried out by the designer; Solispec gives them NG and the array parameters. For apartment and public buildings lightning protection is usually already in the building design, and the PV plant must fit into it. A ground plant is a separate structure, and it is assessed by the same method. In every case the frame is earthed together with the building, and string cables run in pairs so that the loop in which surges are induced stays as small as possible.
How Solispec applies it
Solispec does not perform the full risk assessment: ND needs the tables of DSTU EN 62305-2:2022, which the engine does not hold. The report states that this assessment decides the need for lightning protection and gives a reference NG for the regional centre (≈ 2.0 1/km²·year for Kyiv) as an input for the engineer.
Norms and clauses
- DSTU EN 62305-2:2022
- DBN V.2.5-23:2025, cl. 4.5
- DBN V.1.1-7:2016, cl. 6.45
- NAPB A.01.001-2014, section IV, ch. 1, cl. 1.21
Related terms
- Separation distance s (lightning protection)The minimum gap between a PV array and lightning down conductors at which no spark flashes over (DSTU EN 62305-3:2021, cl. 6.3).
- Surge protective device (SPD)A device that limits lightning and switching surges in PV circuits; its type depends on whether the building has lightning protection.
- PV earthing and equipotential bondingConnecting PV frames, rails and structures to the building’s earthing; under PUE:2026 the earthing must be common with the building.
- Fire-rated cable penetrationThe seal where a PV cable passes through a fire-rated wall or floor; its rating must be no lower than that of the construction.
- DSTU EN 62305-1…4: lightning protection for solar plantsNorms explained
- DBN V.2.5-23:2025 (from 01.01.2026): what applies to solarNorms explained
Solispec’s calculation is preliminary: for a design it has to be checked by an engineer. The values and clauses follow the current editions of the norms on the date of the page.