Solar panel fires on commercial roofs: UK data and causes

Updated 10 November 2026 · SEO Dons Editorial

How many solar panel fires are there on UK commercial buildings?

The most recent published count comes from an insurer, not from government. QBE sent Freedom of Information requests to UK fire and rescue services in February 2026 and reported on 10 August 2026 that they attended 212 fires involving solar panels in 2025, against 91 in 2022. Over those four years QBE puts the rise in fires at 133% and the rise in installations, taken from the government's solar statistics, at 52%. The Fire Protection Association reported the same figures two days later.

Where the fire was reported	2024	2025
Residential property	87	102
Commercial property	33	48
Industrial property	6	14
Solar panel farms	16	14

The table is QBE's, built from responses it dates April 2026. Commercial fires rose by 46% between the two years. Set against the 1,933,148 installations QBE cites for 2025, 212 attended fires is roughly one a year for every 9,100 installations (illustrative arithmetic: 1,933,148 divided by 212). That mixes homes and businesses and rests on incomplete responses, so treat it as a sense of scale, not the risk for one roof.

What can't the published data show?

The headline counts hide several gaps. MHCLG told Parliament on 11 November 2025 that England's Incident Recording System does not record whether an incident involved solar panels, so the department holds no count of call-outs involving them. An earlier answer, on 9 June 2025, said the system does not show whether panels caused or were involved in a fire, nor how they were installed.

The official count is a text search. MHCLG's ad hoc table for England, updated on 29 January 2026 to cover 2010 to 2025, searches the notes typed into incident records. MHCLG warns that the results may be inaccurate or incomplete, that a mention may not be linked closely to the fire, and that some services add no such notes.
Origins often go unrecorded. Cheshire Fire and Rescue Service told a requester in 2025 that its system has no cause, ignition source or item first ignited under which solar panels can be recorded, and Lincolnshire's reply to QBE's questionnaire said the origin of its fires was not recorded.
The insurer's figures move. QBE's release of 3 November 2025 counted 171 fires in 2024, from the 37 of 49 services able to provide data; its August 2026 release gives 155 for the same year. Commercial fires in 2024 appear as 27 in the first release and 33 in the second.
Involved is not caused. QBE counts fires involving a solar panel and MHCLG counts records that mention one, so neither isolates the fires a solar system started.
No rate for commercial roofs. QBE's four location rows for 2025 add up to 178 of the 212 fires, and no count of commercial installations sits beside them, so the figures cannot show whether commercial roofs have fires more or less often than homes.

What causes do investigators and insurers name?

The same causes recur across insurer, fire safety and engineering sources, and most sit on the DC side, between the modules and the inverter.

Cause	What the source says	Source
DC cabling and connectors	The most common origin in 2025, named in 49 fires; QBE ties it to loose connections, damaged wires and faulty wiring that lead to arc faults	QBE, August 2026
DC isolators	Wrongly rated or badly installed isolators are a major contributor to UK PV fires	IET, April 2026
Installation faults	Among the main causes of malfunctions; work without PV competence can leave faults able to start a fire	FPA, February 2024
Product defects	A significant share of fires, where components are of poor quality or incompatible	FPA, February 2024
Panel and inverter	The origin of 36 and 19 fires in 2025; in 2024 the inverter came first, with 21	QBE, 2025 and 2026
Water, dirt and upkeep	Moisture in DC and AC connectors; dirt, bird droppings or leaves causing hot spots; lack of maintenance a contributing factor	FPA, 2024; IET, 2026

The ranking shifts between releases: QBE's November 2025 release put the inverter first for 2024, ahead of the panel and DC cabling, while its August 2026 release puts DC cabling and connectors well clear for 2025. Battery banks were the named origin of 12 fires in 2024 and 23 in 2025; storage has its own fire guidance and is outside this guide.

The BRE study the government published between 2017 and 2019 also recommended better installation practice and changes to how fire and rescue services deal with these fires; the RC62 fire safety guide summarises its component findings. Because workmanship runs through most of these causes, the stages in the guide to commercial PV installations matter as much as the equipment list.

How does the roof under an array change a fire?

The roof build-up matters most once a fire has started. A literature review by OFR Consultants for the Building Safety Regulator, published on 22 December 2025 and updated on 13 February 2026, found that modules often form a semi-enclosed space that traps heat and turns flames back onto the roof. The experiments it reviewed measured heat fluxes of up to 50 kW/m² beneath arrays, against the 12.5 kW/m² considered in standard tests such as BS EN 13501-5, and fire spreading across membranes that current classifications had treated as adequate.

The variables it lists are the gap between panel and roof, the panel's angle and shape, the roof's insulation and membrane, and the array's layout and spacing. It notes that roof classification tests assess the covering without the array, and it recommends non-combustible coverings beneath arrays and design guidance on gap heights and array segmentation. The regulator says the findings are not government policy.

A companion study, eleven large-scale tests by the Health and Safety Executive, found more flame spread on every sample with panels than on the sample without. The tests used pitched residential roofs and the findings are interim, so they show the cavity effect rather than how a warehouse roof behaves. Spread appears in the incident data too: QBE counted 33 fires that spread beyond the solar installation in 2022 and 88 in 2025.

What does the guidance say about DC isolators?

A DC isolator, or switch-disconnector, lets the DC side of an inverter be switched off for maintenance. The IET's Wiring Matters article of April 2026 explains why it is harder to get right than an AC switch: a 50 Hz AC supply crosses zero every 10 milliseconds, which helps put out the arc as the contacts open, while DC has no zero crossing, so the contacts must withstand a stronger and longer arc. Its guidance:

Product standard. A device made to BS EN IEC 60947-3 and marked as suitable for making, breaking and isolating.
Utilisation category. DC-PV0 devices cannot break load current; DC-PV1 can suit circuits without parallel strings; DC-PV2 suits strings connected in parallel.
Rating. Size it from the module maker's figures corrected to worst-case conditions, not the standard test condition values, or the device could fail when switched under load.
Location. Outdoors, bottom-entry glands help keep water out, the fixings must not compromise the enclosure, and a south-facing wall in direct sun brings higher temperatures and more UV.
Inspection. Check the rating and configuration, suitability for its surroundings, terminal torque and conductor ends, and operate the switch with the inverter off.

Isolators belong on the inspection list in the commercial solar maintenance guide, and RC62's own position on separate isolators is set out in the RC62 guide.

What can an owner or facilities manager check or require?

Design and workmanship sit with the installer, but the owner can ask for evidence and write it into the contract:

Isolator selection. The product standard, utilisation category and maximum voltage and current each DC isolator was chosen for.
Connections at every visit. QBE recommends close attention to DC cabling and connector quality at commissioning and at each annual service, and an inspection after high winds, hail or flooding.
The build-up beneath the array. The covering, insulation, membrane and gap under the modules, in writing, since the regulator's review names each as a factor. QBE advises against combustible roofs unless there is proper separation and fire-resistant barriers.
Emergency controls. Where firefighter's switches or arc-fault detection are fitted, QBE asks owners to check that they are correctly installed and accessible.

These are checks, not a design standard. The insurer-backed recommendations that turn them into requirements are explained in the RC62 fire safety guide, and the insurance guide covers what an insurer asks before cover. The commercial PV installations guide sets out the stages at which a buyer can ask for this evidence, and you can send an enquiry through the site's form to ask how a quote covers it.

Sources

QBE European Operations: press releases on solar panel fires of 10 August 2026 and 3 November 2025, checked 10 November 2026.
Fire Protection Association: news report of 12 August 2026 and Are solar panels a fire hazard? (22 February 2024), checked 10 November 2026.
UK Parliament: MHCLG written answers to questions 87241 (11 November 2025) and 54714 (9 June 2025), checked 10 November 2026.
GOV.UK: MHCLG ad hoc table of fires in England with solar panels mentioned in incident notes, 2010 to 2025 (29 January 2026); Fire incidents involving solar panels, BRE study (last updated 19 March 2019); checked 10 November 2026.
Cheshire Fire and Rescue Service, FOI request 2212 (August 2025), and Lincolnshire County Council, FOI 13546113 (8 October 2025), checked 10 November 2026.
Building Safety Regulator, GOV.UK: OFR Consultants' roof thermal exposure review (22 December 2025, updated 13 February 2026), the HSE pitched roof summary (22 December 2025) and the Approved Document B consultation (25 March to 1 July 2026), checked 10 November 2026.
Institution of Engineering and Technology: Solar photovoltaic DC switch-disconnector selection and configuration, Wiring Matters issue 109 (April 2026), checked 10 November 2026.

Common questions

Are commercial roofs more likely than homes to have a solar panel fire?

The published figures cannot answer that. QBE's figures show 102 fires at residential and 48 at commercial properties in 2025, but no count of installations by building type is published alongside them, so neither number can be turned into a rate.

Why can a fire involving solar panels be harder to put out?

The Building Safety Regulator's literature review notes that PV systems working on direct current leave electrical hazards in place even after the power is disconnected. It adds that arrays can block firefighters' access to a fire beneath the panels and impair ventilation systems.

Does a combustible roof make a fire more likely to start?

The sources say more about spread and damage than about ignition. The FPA treats an array on a combustible or partly combustible roof without a fire-resistant covering as a design issue that can damage the building as well as the installation, and the regulator's review found that the space under an array can carry fire across a roof membrane.

Does every commercial array need a separate DC isolator?

Not necessarily. The IET says an inverter needs a means of isolation on both its AC and DC sides for safe maintenance, and treats an external DC switch-disconnector as a designer's choice that must then be correctly rated; under BS 7671 a circuit-breaker suitable for isolation can also be used. RC62's view is covered in the RC62 guide.

Are the building rules for rooftop arrays changing?

Possibly. In its consultation on Approved Document B, which ran from 25 March to 1 July 2026, the Building Safety Regulator proposed fire safety updates for roofs with energy generating installations and said it would examine whether a new testing standard is required. It is analysing the responses, so these are proposals, not guidance.