With over 3 million photovoltaic installations in France and a target of 100 GW by 2050, the solar market is experiencing unprecedented growth. Yet, lightning protection for photovoltaic installations remains a frequently overlooked issue—until the first incident occurs. Lightning rods, surge protectors, grounding: this comprehensive guide explains the regulations, how to size your protection system, and why this step is essential for your solar panels.
Why are photovoltaic installations particularly exposed to lightning?
Photovoltaic power plants are subject to multiple exposure factors:
- Elevated positions : building rooftops, pergolas, ground trackers — panels are often the highest points of a site.
- Large conductive surfaces : the arrays of panels form extended metallic antennas, capturing and propagating the surges induced by lightning.
- High voltage DC cabling : PV installations generate direct current voltages that can exceed 1000 V, which are particularly sensitive to transient overvoltages.
- Expensive electronic equipment : inverters, micro-inverters and power optimizers are costly components and sensitive to indirect lightning.
A single nearby lightning strike can generate surges of several thousand volts propagating through the installation via DC, AC and communication cables — damaging or destroying inverters and modules.
The regulatory framework applicable to PV installations
The protection of photovoltaic installations against lightning is governed by several texts:
IEC 62305 / NF EN 62305: the reference standard
IEC 62305 series of standards (transposed into French law under the reference NF EN 62305) constitutes the main regulatory framework for lightning protection of structures. It is divided into 4 parts:
- IEC 62305-1 : General Principles
- IEC 62305-2 : Risk management (risk analysis and determination of the required level of protection)
- IEC 62305-3 : Physical protection of structures and persons (external protection systems: lightning rods, conductors, earthing points)
- IEC 62305-4 : Power and communication networks in structures (internal protection: surge arresters)
IEC 62305-3 Annex D: Photovoltaic specifications
Annex D of IEC 62305-3 deals specifically with the protection of photovoltaic installations . It covers in particular the positioning of PV panels in protection zones, the separation distances to be observed between down conductors and DC cables, and the rules for grounding chassis.
Order of 26 May 2014 (ICPE installations)
For PV power plants with a power output greater than 250 kW classified as ICPE, the decree of May 26, 2014 requires a lightning risk analysis (ARF) and the implementation of the protections prescribed by the study.
External protection: the lightning rod for PV installations
The purpose of external protection is to intercept the lightning arc before it reaches the panels or equipment, and to channel the lightning current to the ground without damage.
Mandatory preliminary risk analysis
Before any decision is made to install a lightning rod, a risk analysis according to IEC 62305-2 (or the simplified method FD C 17-108 for common structures) must be carried out. This analysis takes into account:
- Lightning strike density Nsg at the site location
- The dimensions of the structure and the panels
- The nature of the equipment and its replacement value
- The consequences of a disaster (business interruption, risks to people)
If the calculated risk exceeds the tolerance threshold set by the standard, the implementation of an external protection system is mandatory.
Early streamer emission (ESE) lightning rod: the ideal solution for PV roofs
For roofs equipped with photovoltaic panels, the early streamer emission (ESE) lightning rod is often the preferred solution because it offers:
- A large protection radius allowing coverage of large areas with a single collection point
- An installation positioned outside the frame (elevated mast) to preserve access to and the aesthetic appeal of the panels
- The possibility of integrating a lightning strike counter ( Contact@ir ) for regulatory verification
The sizing of the PDA (model selection, mast height, positioning) must be carried out by a specialized engineering firm. LPS France offers the Paraton@ir — connected PDAs compatible Contact@ir for intelligent monitoring of your protection system.
Separation distances between down conductors and PV cabling
A critical aspect of the installation: the lightning rod down conductors must not be run parallel to the DC cables of the panels. IEC 62305-3 specifies separation distances calculated based on the protection level (NPF I to IV) and the soil resistivity. In practice, separate insulation or routing is often required.
Internal protection: essential surge protectors
Even if your site is protected by a lightning rod, internal surge protection devices (SPDs) are still mandatory. Indirect lightning (remote strikes) generates transient overvoltages that propagate through electrical and communication networks.
Protection points to be equipped on a PV installation
- DC side : surge arresters at the combiner box level and at the inverter inputs (Type 2 minimum, Type 1+2 if a lightning rod is present)
- AC side : surge arresters at the inverter output and at the main low-voltage switchboard (TGBT)
- Communication networks : surge protectors on monitoring links (RS485, Ethernet, low current)
Lightning arrester coordination
The IEC 62305-4 standard mandates coordination between the different levels of protection (Type 1, Type 2, Type 3) to ensure the effectiveness of internal protection. An installation of uncoordinated surge arresters can be as ineffective as no protection at all.
Grounding: the foundation of all PV lightning protection
The quality of the grounding connection determines the effectiveness of the entire protection system. For a PV installation:
- An earth resistance of less than 10 Ω is recommended (less than 1 Ω for ICPE sites)
- The module chassis, mounting structures, and metal masses must be equipotentially connected.
- The ground connections of the lightning rod and the electrical installation must be interconnected (low-frequency equipotential bonding).
Lightning detection: the first step before any investment
Before deploying a protection system, a lightning risk assessment conducted by a qualified organization is an essential step. It allows you to:
- Objectively assess your site's level of exposure
- Determine the required Lightning Protection Level (NPF) according to IEC 62305-2
- Prescribe appropriate protective measures (nature, location, required performance)
- Justify the technical choices to insurers and regulatory bodies
Conclusion: Protect your solar investment with an integrated approach
A photovoltaic installation represents an investment of tens of thousands of euros for an individual, and several million for a ground-mounted power plant. Lightning protection—external lightning rods and internal surge protectors—is its technical life insurance, at a marginal cost compared to the value protected.
The recommended approach combines:
- A risk analysis according to IEC 62305-2
- External protection designed by a specialist engineering firm
- Coordinated internal protection (DC and AC surge arresters)
- An annual regulatory verification of the protection system
LPS France supports you at every stage : from risk analysis and system sizing to equipment supply and compliance monitoring. Contact our team for a personalized assessment of your photovoltaic installation.
