The periodic general inspection (VGP) of lightning rods is a mandatory regulatory requirement for all operators subject to IEC 62305-3 and NF C 17-102:2011. Indeed, neglecting these inspections not only exposes operators to penalties during regulatory audits, but also risks a failure of protection during a lightning event.
Therefore, this article details the applicable international normative requirements, the different types of verifications required, and the best practices to ensure the conformity of your facilities over time.
The regulatory framework for lightning VGP
At the international level, two standards define the verification and maintenance requirements for lightning protection systems (LPS):
- IEC 62305-3 : Physical protection of structures, applicable in all IEC member countries
- NF C 17-102:2011 : specific to early streamer emission (ESE) lightning rods, adopted in Europe and in many French-speaking countries
These two standards impose the same frequency requirements for visual and full inspections. Therefore, compliance with one covers the frequency requirements of the other.
In practical terms, depending on the sector of activity and the level of risk, additional specific regulations may apply. For example, public access buildings (ERP) and classified installations for environmental protection (ICPE) are subject to stricter controls.
The 3 types of checks required
The NF C 17-102 standard — like IEC 62305-3 — distinguishes three types of verifications, each with its own frequency and level of requirement:
1. Visual inspection (annual)
A visual inspection is an examination without dismantling or instrumented measurements. It must be carried out at least once a year and covers the following points:
- Lightning rod integrity (no deformation, corrosion, or missing parts)
- Condition of the down conductors (visual continuity, fixings, absence of through corrosion)
- Compliance with separation distances (check if new elements have been added)
- Status of Equipotential Spark Gap and mechanical protection
- Surge protector end-of-life indicators (indicator light, trigger)
- No visible damage from a recent lightning strike
2. Full inspection (every 2 years)
The full verification covers all the points of the visual inspection and adds instrumented measurements. Furthermore, it is essential to ensure that the installation's performance has not deteriorated over time.
- Measurement of the resistance of each ground connection (target ≤ 10 Ω)
- Comparison with the initial value of the execution file (⚠️ any variation > 50% must be analyzed)
- Electrical continuity test of the entire circuit (lightning rod → down conductors → grounding points)
- Verify that the ESE is functioning correctly according to the manufacturer's procedure
- Continuity of conductors integrated into the structure (concrete reinforcement, embedded downpipes)
3. Post-impact verification detected
As soon as an impact is detected on or near the installation, immediate verification is essential. This is one of the most frequently overlooked requirements, as it presupposes the availability of a reliable detection system.
Nevertheless, this post-impact check is crucial to ensure that the system has performed its function correctly and that no components have been damaged during the discharge.
The execution file: the key document
Even before discussing periodic checks, everything starts with the execution file. This document, created at the end of the installation, is the basic reference for all subsequent checks.
It must absolutely contain:
- The level of protection selected (I, II, III or IV according to IEC 62305 / NF C 17-102)
- The type of lightning rod and its characteristics (model, ΔT for ESEs)
- The number of downhill drivers and their route
- The type and values of the earth connections measured at commissioning
- The calculated separation distances and the Equipotential Spark Gap established
This file serves as a reference for comparing subsequent measurements and justifying any changes to the installation. Without this document, the audit becomes an investigation.
The verification report: a mandatory document
Each inspection – visual, comprehensive, or post-impact – must be documented in a detailed report. This report is a mandatory document and must be kept with the project file.
It must contain:
- Installation identification (address, file reference)
- The type of verification carried out and the date
- The results for each item on the checklist
- The measured values compared to the reference values
- Corrective measures to be taken, with priority level
- The identity and qualifications of the auditor
- The date of the next recommended check-up
Thus, in the event of a regulatory inspection, the operator can demonstrate compliance over the entire lifespan of the installation.
Connected maintenance: a decisive advantage for ESEs
Early streamer emission (ESE) lightning rods offer a significant advantage over Franklin rods: the possibility of connected maintenanceESEs LPS France equipped with the Contact@irsystem allow:
- Automatic detection of each impact on the installation
- Sending an immediate notification to the manager
- The automatic triggering of a post-impact verification procedure in LPS Manager
- The instant generation of a time-stamped report
Therefore, proactive monitoring allows for preventive intervention before failure, unlike the reactive approach of the Franklin lightning rod which only detects anomalies at the time of scheduled verification.
To discover the available connected lightning rods, consult the Paraton@ir and Ellips from LPS France.
Conclusion: Compliance, an ongoing process
Periodic general verification is not a one-off requirement—it's an ongoing process that ensures the long-term reliability of your lightning protection. In summary, the requirements of IEC 62305-3 and NF C 17-102 are based on three pillars: annual visual inspection, biennial full verification, and systematic post-impact inspection.
Ultimately, operators who digitize this process with tools like LPS Manager significantly reduce their administrative burden while strengthening their actual level of compliance. To install or upgrade your system and then monitor it, discover the complete range of LPS France.
