Lightning Protection Norms: Why the Old Standard Was Withdrawn and What Applies Now

What was withdrawn and when

DSTU B V.2.5-38:2008 “Building services. Lightning protection of buildings and structures” was withdrawn on 1 November 2019 by Order No. 313 of the Ministry of Regional Development dated 16.10.2019.

What applies instead

Lightning protection is now designed to the DSTU EN 62305 series (harmonised with the international IEC 62305), which has four parts:

• DSTU EN 62305-1 — general principles;
• DSTU EN 62305-2 — risk management;
• DSTU EN 62305-3 — physical damage to structures and life hazard (the main part for external protection and zone calculation);
• DSTU EN 62305-4 — electrical and electronic systems within structures.

What changed in the approach

The main difference from the old national standard is a formal risk assessment (DSTU EN 62305-2): the required level of protection comes from a risk calculation for the specific object, not from one universal rule. Instead of the old fixed protection categories, the new series uses four lightning protection system (LPS) classes (I–IV, from the highest to the lowest protection level), each with its own zone calculation parameters — see Calculating a Lightning Rod’s Protection Zone.

What this means in practice

A design made under the withdrawn DSTU B V.2.5-38:2008 formally no longer complies with current norms. For new projects and documentation updates, use the DSTU EN 62305 series.

Editions in force

The DSTU EN 62305 series was updated part by part, so a design should name the edition of each part. As of October 2026, public regulatory databases show this:

The 2021 edition of Part 3 was adopted by Order No. 490 of the state enterprise UkrNDNC dated 09.12.2021. New editions may appear: check the list before starting a design.

Example: class and protection zone

Take a single-rod air-termination with h = 6 m and the rolling sphere formula R = √(h × (2r − h)); r and R are as in the table.

Between classes I and IV the protection radius differs 1.8 times and the ground-level protected area about 3.4 times. So class I instead of IV calls for a taller mast or more masts on the same site. This is a simplified illustration for one rod on level ground; a real structure needs a full calculation under the standard.

Down-conductors and earthing (Part 3)

A non-isolated system needs at least two down-conductors distributed around the perimeter; equal spacing between them is recommended, and a down-conductor is to be placed at each corner of the structure where possible (cl. 5.3.3). Typical distances are in the table under “What depends on the system class”.

Example. A 60 × 30 m building has a 180 m perimeter, so the typical distances give 18 down-conductors for classes I–II, 12 for III and 9 for IV.

A low earthing resistance is recommended for the earth-termination: up to 10 Ω, where possible, measured at low frequency (cl. 5.4.1). The standard distinguishes type A (separate electrodes at each down-conductor) and type B (a ring or foundation electrode). For 0.4–10 kV networks the Ukrainian Electrical Installation Rules (PUE) set their own norms — see earthing of lighting and line poles.

What is in Part 3 and what is mandatory

DSTU EN 62305-3:2021 is an identical (IDT) translation of the European EN 62305-3:2011. It covers physical damage to a structure from lightning and the danger to people from touch and step voltage near the LPS; surge protection of electronics is EN 62305-4. Clause 4 gives the LPS class; 5 the external system (air-termination, down-conductors, earth-termination, materials, sizes); 6 the internal one (equipotential bonding, separation distance s); 7 inspection and maintenance; 8 touch and step voltage.

The table of contents marks Annexes A (air-termination layout), B (incoming cable screen) and D (structures with an explosion risk) as normative (mandatory), and C (separation distance), E (guidance on design, installation, maintenance and inspection) and NA (national standards) as informative. So the intervals of Table E.2 and the advice in Annex E are recommendations, not requirements. The need for inspections comes from the main text (cl. 7.3): an LPS is inspected after installation, periodically (the intervals depend on the structure: corrosion problems and the LPS class), after alterations or repairs and after a known lightning strike.

What depends on the system class

The LPS class (I–IV) matches the lightning protection level LPL I–IV (cl. 4.1) and sets several parameters; those most needed for masts are below. Not class-dependent: sheet and tube thickness in the air-termination (Table 3), materials (Table 5), minimum conductor and electrode sizes (Tables 6–9) and internal protection, except the separation distances; electrode length l1 does depend on the class.

l1 is read from a graph (about ±1 m); for classes I and II it stays 5 m until soil resistivity ρ passes roughly 500 and 800 Ω·m, then grows. If the earthing resistance, measured at a frequency other than the power frequency and its multiples, is below 10 Ω, these lengths may be disregarded (cl. 5.4.2.1).

Intervals in Table E.2

Table E.2 is informative; its intervals are maxima. For critical cases (sensitive internal systems, places with many people) the third column sets a full inspection every year, and for structures with explosive materials footnote a sets a visual inspection every 6 months. The text under the table says visual inspection at least once a year. The authorities or an insurer may require other intervals.

Standard terms and names in documents

Checklist: does the design comply with current norms

• the explanatory note cites the DSTU EN 62305 series with editions (for Part 3 — 2021), not DSTU B V.2.5-38:2008;
• a Part 2 risk assessment has been done and the system class (I–IV) chosen from it;
• the zone method suits the structure’s geometry, and the gaps between several air-terminations are checked;
• each mast has a defined down-conductor (its own steel shaft or a separate conductor) and earth electrode type;
• electronics protection inside the structure is a separate Part 4 section;
• the earthing resistance is to be measured after installation.

Typical mistakes when moving to the new norms

• carrying a category from an old design over as a class: the class (I–IV) is determined anew from the risk assessment;
• always taking the highest class “just in case”: as the example shows, that means much taller or more masts;
• applying the single-rod formula to several air-terminations or a complex shape.