The photovoltaic installation market is experiencing unprecedented growth: residential rooftops, parking lot canopies, large solar farms — panels are multiplying on every continent. With them, one question consistently arises: how to protect these installations against lightning?
The answer is not straightforward. A PV installation combines two distinct risks: a direct lightning strike (managed by the lightning rod) and induced overvoltage (managed by the surge protector). These two protections are complementary, not interchangeable.
This comprehensive guide explains the normative requirements ( IEC 62305 ), the available technical solutions, and the specific points of vigilance for PV systems.
Why photovoltaic installations are particularly vulnerable to lightning
Solar panels have several characteristics that increase their sensitivity to lightning:
- Exposed location : rooftops, heights, open areas — configurations that favor direct impacts
- Extensive cabling : tens or hundreds of meters of DC cables form large inductive loops that capture overvoltages.
- Sensitive electronic components : inverters, MPPT converters, monitoring systems — all vulnerable to voltage transients
- High value : a 100 kWp installation represents €60,000 to €100,000 worth of equipment.
According to claims data from specialist insurers in Central Europe (Germany, Austria, Switzerland), lightning accounts for between 15 and 25% of damage to insured PV installations , with an average cost per claim between €4,000 and €20,000.
The regulatory framework: IEC 62305 and its applications for photovoltaics
The international standard IEC 62305 (Lightning Protection) provides the overall framework. It is divided into 4 parts:
- IEC 62305-1 : General Principles
- IEC 62305-2 : Risk assessment — Nsg calculation and protection sizing
- IEC 62305-3 : Physical protection of structures (lightning rods, down conductors, grounding connections)
- IEC 62305-4 : Protection of electrical and electronic systems (surge arresters, cabling, equipotential bonding)
For PV installations, IEC 62305-3 and IEC 62305-4 are both relevant . The supplementary standard IEC 60364-7-712 deals specifically with PV installations and specifies the requirements for overvoltage protection.
Protection against direct lightning: the role of the lightning rod
An early streamer emission (ESE) lightning rod protects a defined area against direct lightning strikes by creating a conical protection zone around the point of capture.
When is a lightning rod necessary for a PV installation?
The decision is based on an IEC 62305-2 risk assessment which takes into account:
- The local Nsg (lightning strike density in the air, impacts/km²/year)
- The effective collection surface area of the installation
- The potential consequences (people, equipment, environment, heritage)
- The acceptable level of risk according to the structure category
For many residential rooftop PV installations, the risk study concludes that the lightning rod is not mandatory — but that surge protection (IEC 62305-4) is systematically recommended .
ESE or single-point lightning rod? The right choice for a PV installation
For large solar farms or PV installations on industrial buildings, an EMF (early flashing lightning rod) like the Paraton@ir offers an extended protection radius covering a large area with a single capture point.
Advantages for PV installations:
- Protection radius can exceed 100 m depending on the device class
- Integration of the lightning strike counter (Compt@ir or Contact@ir) for monitoring impacts
- Simplified implementation on large surfaces
Surge protection: the role of the surge protector
Even if your PV system isn't directly struck, a nearby lightning strike generates induced electromagnetic interference that propagates through your DC and AC cables. These overvoltages are the primary cause of inverter failure .
Surge protection architecture for a PV installation
Effective protection requires a multi-level approach:
- Level 1 (DC side) : Class II (Type 2) surge arrester installed at the output of each string or at the junction box
- Level 2 (AC side) : surge arrester at the inverter input, grid side
- Level 3 (measurement/monitoring equipment) : data line protectors if wired communication is present
In areas with high lightning density (Nsg > 2.5 impacts/km²/year), Class I + II (Type 1+2) may be required on the DC side.
Equipotential Spark Gap: the often-neglected golden rule
Equipotential bonding involves connecting all the metallic masses of the installation (supporting structures, panel frames, enclosures) to the same earthing network. It is the most important and most often neglected element in PV installations.
Without proper Equipotential Spark Gap, even an excellent surge arrester cannot effectively dissipate induced overvoltages.
Specific points of concern for large solar farms
For installations ranging from several hundred kWp to a few MWp (the rapidly growing Spanish, Portuguese, and North African markets), additional precautions are necessary:
- Earth resistance : aim for < 10 Ω, ideally < 5 Ω on resistive soils (sands, limestones)
- DC wiring : limit large inductive loops by running the positive and negative cables together
- Central inverters : close protection required, automatic disconnection recommended
- SCADA and monitoring systems : protectors on all wired communication links
Monitoring and maintenance of lightning protection for a PV installation
A lightning protection system is only effective if it is regularly maintained and inspected according to IEC 62305-3. For PV installations, this includes:
- Annual verification of grounding connections (resistance measurement)
- Visual inspection of surge protectors (replacement indicator)
- Lightning strike counter readings taken after each storm season
- Compliance documentation update
For multi-site solar parks, LPS Manager centralizes these operations: real-time impact data, maintenance planning, automatic generation of IEC 62305 compliance reports. No more need to manage Excel files per site.
Conclusion: Appropriate lightning protection safeguards your photovoltaic ROI
Investing in lightning protection for a PV installation is not an abstract regulatory constraint — it is a direct protection of the return on investment of your solar power plant .
An inverter destroyed by an unprotected power surge can cost between €5,000 and €30,000 and disable the installation for several weeks. Complete protection (lightning rod + surge protectors + Equipotential Spark Gap) rarely represents more than 1 to 3% of the total installation cost.
To size your protection and choose the appropriate equipment, consult LPS France lightning rods or contact our technical teams for a personalized study according to IEC 62305 .
