Norms · DBN V.2.5-23:2025
DBN V.2.5-23:2025 (from 01.01.2026): what applies to solar
From 1 January 2026, electrical installations of residential and public buildings are designed to the new edition, DBN V.2.5-23:2025. The code is not about solar panels as such, but a rooftop PV system lives inside that installation.
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Edition and status
DBN V.2.5-23:2025 was approved by Ministry for Development order No. 1301 of 25.08.2025 and is in force from 01.01.2026, replacing the 2010 edition. Status as of 14.10.2026 per the norms register Solispec checked on 04.10.2026.
The official text: Building norms register, e-construction.gov.ua. Solispec does not host the norm texts. Look for the current edition at the official source.
Scope and references
The code covers residential and public buildings (clause 1.1). Fire requirements for electrical equipment are referred to other documents (clause 4.1), among them DBN B.2.2-12:2019 and DBN V.1.1-7:2016. DBN B.2.2-12:2019 replaced DBN 360-92, cancelled from 01.10.2019. For PV plants themselves, a note in section 5 refers to separate standards on design and grid connection of photovoltaic stations.
Lightning protection and SPDs
Clause 4.5 refers lightning protection to DSTU EN 62305-1…4. Clause 8.6 requires protection against lightning and induced overvoltages with surge protective devices per DSTU EN 62305-4:2012. So for a house with PV the first step is a risk assessment, and that tells whether external lightning protection is needed.
Cable routes and penetrations
- Clause 7.62: a cable through a fire-rated wall or floor passes only through a tested EI or E class fire-stop penetration, never in sleeves or ducts of combustible material.
- Clauses 7.53 and 7.54: no risers in stairwells and no open cables along a stairwell. For PV on an apartment block, the route from the roof to the switchboard has to go another way.
- Clause 8.7: conductor cross-sections are chosen by heating under the continuous design current and checked for voltage drop. For PV cables the code’s reference list gives DSTU EN 50618:2018.
How Solispec applies it
Solispec takes from this code what concerns the array: in the fire-safety hints, penetrations per clause 7.62 and no route through stairwells per clauses 7.53 and 7.54; in the lightning hint, clause 4.5’s pointer to the risk assessment. The engine sizes the DC cable by current (the Iz of H1Z2Z2-K cable from the maker’s datasheet) and by voltage drop. The 1.5 % drop target is the app’s own target, not a norm.
Terms
- 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.
- Lightning risk assessmentThe DSTU EN 62305-2:2022 calculation deciding whether a building with PV needs external lightning protection; there is no "PV means LPS" rule.
- 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.
- PV DC cableThe cable between the panels and the inverter; its section is chosen by I_SC MAX at 70 °C and checked for voltage drop.
- 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.
- Combustible roofs and PV cablesNAPB forbids external wiring over combustible roofs; on bitumen shingle or onduline, DC cables run in metal trays or conduit.
Other norms
- PUE:2026 for solar plants: what changedPUE:2026 replaced PUE:2017: scope, common earthing with the building and surge protection for a solar plant.
- DSTU HD 60364-7-712:2022: the electrics of PV systemsUkraine’s main PV electrical standard: U_OC MAX in frost, I_SC MAX, string fuses, cables under modules, SPDs and earthing.
- DSTU EN 62305-1…4: lightning protection for solar plantsThe four parts of DSTU EN 62305-1…4 for a solar plant: risk assessment, separation distance, SPDs. There is no rule that PV always needs lightning protection.
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.