Photovoltaic System Fire Risk

Hazard picture

Unlike faults in conventional AC installations, DC-side arc faults in PV strings do not necessarily trip protection because there is no zero crossing; they can smoulder undetected for hours. Additional risk sources include substandard connectors, thermally overloaded cables underneath the module surface, rodent damage and installation errors in the mounting structure. On roofs, modules and wiring also complicate firefighting, since live conductors pose a hazard to fire crews.

Protective measures

Key measures are proper design and testing of the DC side including arc-fault detection, fire-safe spacing between module fields to preserve escape routes and firefighting access, and recurring inspection under recognised regimes including thermographic scanning and I-V curve measurement. For existing roofs, the compatibility of PV loading with the roof waterproofing and the fire resistance of the roof construction must be verified.

Insurance relevance

For standalone photovoltaic insurance and property insurance of the building, documentation of the commissioning test and recurring inspections is a key criterion for risk classification. Missing clearances to combustible roof structures or unclear separation from battery storage are treated as aggravating risk factors.