Fire Protection for Solar PV Systems

Understanding the risks and how to reduce them

Solar photovoltaic (PV) systems are playing an increasingly important role in the transition to renewable energy, with installations continuing to grow across commercial, industrial and residential buildings. While PV technology is proven, reliable and inherently safe when correctly designed and maintained, the rapid growth in installations has brought greater attention to the fire risks associated with electrical faults, ageing components and environmental exposure.

This article explores where those risks exist, the real-world impact of recent solar-related fires, and why early detection is becoming an important consideration for building owners, installers and insurers alike. It also looks at how technologies such as Linear Heat Detection (LHD) can provide continuous monitoring of high-risk areas, helping identify overheating before it develops into a fire and supporting safer, more resilient solar PV installations.

Where are the risks in PV applications? 

Solar panels on commercial buildings provide a unique way to produce energy without taking up additional usable space in and around a building. However, physical layout of a solar array also presents unique protection challenges. Large rooftop installations, long cable runs, and hidden voids beneath panels can make faults difficult to identify during their early stages. They are often not visible from the ground or from regular access points, so any issues are not easily spotted. Once installed, many components are not easily accessible for routine inspection, making it important to detect abnormal conditions before they develop into a fire.

Installation Risks

The most common causes of fires relating to solar panels come from the connectors that transport the generated energy into the desired location. Fires often originate from poor electrical connections, damaged or incompatible connectors, DC arc faults and inverter failures. Localised hotspots can develop where electrical resistance increases, producing heat long before visible signs of failure appear.

Environmental Factors

Other risks come from long term wear and tear and other environmental factors. Being installed outside and most of the time on rooftops, PV systems are exposed to damage caused be natural factors such as UV degradation and water damage where cables may not be properly secured or in IP rated casings. The system is also exposed to wildlife. Rodents are prone to chewing on cables, exposing conductors, while some birds have taken to dropping stones on the panel face which if broken can cause electrical damage leading to a fire.

The real impact of solar related fires

Although solar related fires remain rare compared with the number of PV systems installed worldwide, the consequences can be significant when they do occur.

Beyond the immediate damage to buildings, a fire can lead to:

• Disruption to business operations
• Risks to occupant safety
• Lengthy insurance claims
• Reduced confidence in renewable energy technologies

In some cases, fires may also involve battery energy storage systems, where thermal runaway can create a chain reaction that becomes difficult to control once established.

Impact on confidence

The wider impact of these incidents is already being seen. Earlier this year, a network of 80 schools in Sussex switched off the solar PV systems across all of its sites after three separate fires were linked to installed PV systems (Cunningham, 2026).

While investigations continue, the incidents show how a relatively small number of fires can affect confidence in an entire technology. Importantly, these incidents are not necessarily a failure of renewable energy itself, but are more commonly associated with the specification, installation or ongoing maintenance of electrical systems.

Residential installations

The same considerations apply to domestic installations, which continue to grow as homeowners look to reduce energy costs.

When a fire occurs at a residential property, the impact can extend beyond a single home. Closely spaced housing may increase the risk of fire spread, while smoke, emergency response activity and road closures can disrupt the surrounding community.

Higher risk buildings

The type of building can also influence the severity of a fire. Cold storage warehouses, for example, often use solar PV to offset high energy demands, but many are constructed using highly combustible insulated panels.

If a fire develops, these materials can allow it to spread rapidly and make extinguishment far more challenging.

A recent fire at a cold storage warehouse in the Boyle Heights area of Los Angeles, where solar PV is believed to have been the source of ignition, burned for more than a week before it was brought under control. The building was ultimately declared beyond repair, while local residents experienced prolonged disruption, poor air quality and persistent smoke odours (The Associated Press, 2026).

Protecting what matters most

These risks are not intended to discourage the use of solar as a renewable energy source, where the benefits speak for themselves. Fire risk management starts with good system design, quality components and competent installation, supported by regular inspection and maintenance throughout the life of the system.

Even well installed systems can develop faults over time, which makes early detection an important additional layer of protection.

Linear Heat Detection (LHD) is a cable based heat detection technology that senses along the entire length of the cable. It can be installed directly beneath the solar panels, across the array and around connection points where overheating is most likely to occur.

Key benefits include:

• Continuous coverage across areas that point detection may not reach
• Resistance to wind, dust and other environmental conditions
• Suitable for both new installations and retrofit applications
• Can be connected to the building's existing Automatic Fire Detection system
• If a fire is detected, the system can trigger the building alarms and any associated evacuation alerts.

While there is currently no legislation requiring detection within PV applications, insurers including Aviva, Zurich and Allianz are increasingly recommending or requiring additional detection within their guidance. This reflects a growing awareness among insurers and Fire Risk Assessors of the potential fire risks associated with PV systems.

How can Thermocable help?

Thermocable is a world leading manufacturer of cable-based sensing and detection technologies based in the UK. Our ProReact - Linear Heat Detection range is for temperature sensitive environments when early detection of an abnormal change is crucial. From stainless-steel braiding for harsh environments, to various mounting clips to fit any application, we can support with product selection and design, through to providing technical support through the installation and commissioning process.