Why is a lightning protection inspection important?
- Preventing fires and injuries – a faulty lightning protection system can cause extensive damage
- Obligation – LPS inspections are imposed on operators by Government Decree No. 190/2022 Coll., and insurers often ask for the report too
- Smooth occupancy approval – initial inspection of new buildings
- Protection of electronics – reducing the risk of overvoltage
How often must a lightning protection system be inspected?
The intervals are set by Annex 4 of Government Decree No. 190/2022 Coll. (effective 1 July 2022). The inspection is carried out in the year in which the interval ends, and if several intervals apply to the equipment, the shortest one applies.
- Ordinary buildings including family houses – a full inspection every 4 years
- LPS protecting critical systems – every 2 years (this can also include office and commercial buildings with sensitive internal systems)
- Buildings with a risk from explosive materials – a full inspection every year and a visual check at least every 6 months
- Visual check that the lightning protection is not visibly damaged – at least once a year
- After a lightning strike, damage, or a change to the roof or building – an extraordinary inspection
Service check and maintenance of the lightning protection system
Between inspections the system is maintained: at least once a year a visual check is carried out that the lightning protection is not visibly damaged (Annex 4 of Government Decree No. 190/2022 Coll.). A service check includes inspecting air terminals and down conductors, cleaning and tightening clamps, checking test clamps and protection against corrosion.
After an inspection we remove the faults found, for example loose or corroded clamps, an unfastened air-termination conductor or missing anti-corrosion coating, and verify the result with a control measurement.
A check, or an inspection of the lightning protection?
A visual check (at least once a year) verifies that the lightning protection is not visibly damaged. A full lightning protection inspection also includes measuring the earthing and continuity, an assessment against the standard valid at the time of installation and the issue of an inspection report – normally every 4 years, every 2 years for critical systems and every year for areas with explosive materials.
Which standard is used to assess a lightning protection system
The inspection technician assesses the system according to the standard valid when it was installed. Older systems installed up to 31 January 2009 are assessed under ČSN 34 1390, newer ones under the ČSN EN 62305 series. Since October 2025 ČSN EN IEC 62305-1 ed. 3 has been published; it applies in parallel with ed. 2 until 31 October 2027.
The inspection report therefore states the year of installation, the governing standard, the measured earth resistance of each down conductor and any faults with a reference to the breached clause of the standard.
How does the inspection work?
- Visual check of down conductors, earthing and joints
- Measurement of earth resistance
- Check of connections and continuity of the system
- Preparation of the inspection report
Frequently asked questions
How often must a lightning protection system be inspected on a family house?
Usually every 4 years (Annex 4 of Government Decree 190/2022 Coll.), and at least once a year a visual check is carried out that the lightning protection is not visibly damaged. After a lightning strike, damage or a change to the roof an extraordinary inspection is carried out.
Is a lightning protection inspection mandatory?
The obligation to inspect designated electrical equipment, including LPS, follows from Act No. 250/2021 Coll.; the intervals are set by Annex 4 of Government Decree No. 190/2022 Coll. An initial inspection is needed for new buildings and after modifications to the system. For a family house without business activity we recommend keeping the same intervals; insurers often ask for the inspection report in the event of storm damage.
Which standard is used for a lightning protection inspection?
The standard valid when the system was installed: up to 31 January 2009 ČSN 34 1390, later the ČSN EN 62305 series. The inspection report states the governing standard and the year of installation.
What is the earth resistance limit of a lightning protection system?
For old systems under ČSN 34 1390 the earth resistance of one down conductor should not exceed 15 Ω. For newer ones under ČSN EN 62305-3 the recommended value for the whole earthing system is up to 10 Ω. We state the specific limit in the inspection report.
What does a lightning protection measurement include?
Visual inspection of air terminals, down conductors, clamps and corrosion, measurement of the earth resistance of each down conductor, a check of the continuity and connection of the system and an assessment of separation distances. The result is an LPS inspection report with faults and proposed measures.
What if the lightning protection fails the inspection?
In the inspection report we state the faults, the non-conformity with the standard and a proposed repair, for example cleaning and tightening clamps, anti-corrosion coating or repair of the conductor. After the faults are removed, a follow-up inspection can be done.
How much does an inspection cost? You will find indicative prices in the price list →