DC Cabling Failures, Battery Storage Fuel 133% Jump in UK Solar Fires

Fire Rate Outstrips Solar Rollout as UK Installations Pass Two Million

Solar panel fires in the UK jumped 133% between 2022 and 2025, more than double the 52% growth in installations over the same period, according to Freedom of Information responses obtained by QBE Insurance from 46 of 49 UK fire services. UK fire crews attended 212 solar‑related fires last year, up from just 91 in 2022, while the national installation count passed two million for the first time in March 2026.

DC cabling and connectors are now the leading ignition source, causing 49 fires in 2025—nearly double the 26 recorded in 2024. Solar panels themselves accounted for 36 fires, battery banks for 23 and inverters for 19. Adrian Simmonds, risk manager at QBE, directly links the cabling trend to installation quality: loose connections, damaged wires and faulty wiring create arc faults and other electrical failures.

The gap between adoption and fire safety is sharpest in commercial and industrial buildings, where fire incidents rose 46% and 133% respectively in a single year. Additionally, fire severity is worsening; the number of blazes spreading beyond the solar installation nearly tripled, from 33 to 88. Lithium‑ion battery storage—now standard in many systems—introduces thermal runaway, requiring up to ten times more water to contain and leaving insurers working with incomplete loss data. Many policyholders treat solar systems as “fit and forget”, but a growing number of insurers now require proof of Microgeneration Certification Scheme (MCS) installation as a condition of cover, marking a shift towards treating installation quality as a core underwriting variable.

Why Installation Quality and Battery Placement Are Resetting Solar Risk Models

The DC Cabling Problem and the Accreditation Gap

The dominance of DC cabling as a fire cause points squarely at installers who may not follow MCS standards. QBE’s Simmonds stresses that every system—whether on a home, warehouse or solar farm—should use MCS‑accredited firms and receive consistent maintenance. AXA UK separately flagged solar fire risk after 2024 blazes at a Lidl warehouse, a Lewisham block of flats and a Cramlington school, reinforcing the view that installation quality, rather than age or panel type, drives risk. As MCS certification becomes a de facto underwriting requirement, brokers who gather that documentation early position their clients more favourably in a tightening market.

Battery Storage: A Severity Multiplier

Lithium‑ion battery fires cause thermal runaway—a self‑sustaining overheating reaction triggered by impact, overcharging or external heat. QBE’s research found UK fire brigades tackled a lithium‑ion battery fire once every five hours in 2025. For insurers, the scarcity of granular loss data on battery‑related solar fires creates significant pricing uncertainty, which typically translates into higher premiums and tighter terms. Battery placement compounds the problem; units in confined or hard‑to‑access spaces hamper both inspection and emergency response, a risk Simmonds says is often overlooked.

Commercial and Industrial Buildings Face Fastest‑Rising Fire Risk

Commercial property solar fires rose from 33 in 2024 to 48 in 2025, while industrial building fires jumped from six to 14—a 133% single‑year increase. These sectors are exactly where the government’s Solar Roadmap and Clean Power 2030 mission plan to concentrate new rooftop capacity. The Future Homes Standard, taking effect in March 2028, will mandate onsite renewable generation in all new‑build homes, further expanding the asset class. Without a corresponding uplift in installation standards and inspection regimes, the divergence between fire frequency and installed capacity will widen.

Policy Mandates Collide with Underwriting Reality

Government pressure to decarbonise the built environment is rapidly increasing solar exposure, yet the data shows the risk is poorly controlled at the installation level. AXA’s observation of a “fit and forget” culture among policyholders matches QBE’s finding that many fires stem from wiring faults that routine maintenance would catch. This misalignment is unlikely to resolve itself quickly; regulators and the market will need to settle on a consistent standard for what constitutes an insurable solar‑plus‑battery risk. Until then, the insurance response is likely to be more demanding documentation, narrower cover and differentiated pricing for risks that can demonstrate robust installation and maintenance records.

What Brokers and Property Owners Must Verify Before the Next Solar Fire

For insurance brokers and underwriters:

• Request the client’s MCS certificate and installer accreditation number directly for every new or renewing solar‑equipped risk; do not accept a general assurance of professional installation. A genuine MCS certificate names the accredited installer and confirms the specific assessment standard, which insurers increasingly want on file if a cabling‑related claim occurs.
• Document the exact location of any lithium‑ion battery storage unit and confirm it is genuinely accessible for inspection and emergency response. QBE’s Simmonds flags unit placement in confined or hard‑to‑access spaces as a critical, often‑overlooked factor that both raises fire likelihood and makes containment harder.
• For commercial and industrial properties, incorporate battery fire scenarios into risk assessments, including the water supply requirements (thermal runaway fires can demand up to ten times more water) and ventilation access.
• Include solar system maintenance records in the renewal file; the sharp rise in DC cabling fires correlates with installation quality, and evidence of regular professional inspection can strengthen a submission relative to one that simply notes “solar panels present”.

For property owners and facilities managers:

• Only use MCS‑accredited installers for any solar or battery storage work and keep the certificate and accreditation number readily available for your insurer.
• Schedule annual professional inspections of DC cabling, connectors and battery units—do not treat the system as “fit and forget”. Loose connections and damaged wires can develop over time and account for the largest share of fires.
• Ensure battery storage units are placed in well‑ventilated, easily accessible locations, away from combustible materials. If a unit must be in a confined space, discuss fire suppression and detection options with a qualified installer and inform your broker.