Rooftop photovoltaic arrays: Electric shock and fire health hazards

Electric shocks and fires represent two different ways for rooftop photovoltaic energy systems to affect public health adversely during installation, operation or removal. Analysis of a U.S. Department of Energy residential application demonstration project suggest that the voltage generated by six modules connected in series could be sufficient to cause ventricular fibrillation and possibly death. Extrapolation of these results to future installations is limited by lack of failure mode data for various designs representing state-of-the-art module and rooftop applications. Two causes of fire include (i) electrical fires from short circuits and (ii) spontaneous combustion from heat build-up in dead air space. Crude upper-boundary estimates for fire-related risk are less than one reportable fire and less than 10−2 deaths per year per 10 MWp cumulative installed capacity. Although the marginal risk to society from these hazards may low, the potential risk to exposed individuals is high. Continued evaluation of safeguard effectiveness merits further consideration.