Arc fault reported in rooftop solar fire at Peterborough warehouse
EIR-1155Provisional entry. Confirmed: a rooftop solar array fire at a large distribution warehouse at Alwalton Hill, Peterborough, tackled by eleven engines and more than fifty firefighters, with damage confined to the roof and the cause recorded as accidental. Not yet confirmed: the exact date, the operator or owner, the PV equipment involved, and the specific component that failed. Next update: 22 September 2026.
A fire broke out among rooftop solar panels on a commercial distribution warehouse at Alwalton Hill, on the southwestern edge of Peterborough beside the A1(M), reported to have occurred on a Friday afternoon in February 2024. The roof covered about 484,000 square feet and carried 21 rooftop solar arrays supplying roughly a tenth of the building's electricity. Crews from nine fire stations plus two roaming engines, eleven fire engines in total, were called shortly before 2pm. More than fifty firefighters, supported by a turntable ladder and a water carrier, worked the fire in breathing apparatus using hose reels. The fire stayed on the roof and did not spread into the building, and the distribution centre resumed operating almost immediately. All crews had returned to their stations by 7:40pm. The fire service recorded the cause as accidental. This entry is based on a single secondary report.
The fire is reported to have started as a direct current arc fault. Unlike alternating current arcs, a DC arc does not self-extinguish because the voltage never passes through a zero crossing. Cutting power at the building breaker does not de-energise the panels themselves, which remain live in daylight. Corrosion or imperfect seating at panel-to-panel connectors is cited in general terms as a common origin point for such arcs, but the specific failed component in this fire was not reported.
- Arc fault detection and rapid shutdown provisions should be fitted and maintained on commercial rooftop PV arrays so that conductors outside the array boundary can be brought to a safe voltage for responders.
- Periodic thermal imaging surveys of panel connectors and DC wiring can identify overheating joints before they ignite, at a cost that is small next to a roof fire.
- Fire services and site operators need arrangements specific to large commercial arrays, including knowing the array boundary, arranging aerial access at height, and understanding that isolating the building supply does not de-energise the modules.
Published 2026-09-21. Written from public reporting. Descriptive, not investigative. See the data accuracy disclaimer.