The rapid development of the solar industry over the past several years has expanded the significance of photovoltaic (PV) systems. Fault analysis in photovoltaic arrays is a fundamental task to increase reliability, efficiency, and safety in PV systems. If no fault is detected, it may reduce power generation, accelerate system aging, and increase the risks of fire hazards. In this study, we considered the line–line fault through verification experiments in PV arrays for fire hazard analysis and analyzed accident characteristics to improve electrical safety in PV systems. This paper presents a comparison and analysis of accident characteristics regarding the location of the accident, use of blocking diodes, and PV inverter operation. String line–line fault protection in systems without blocking diodes should be designed considering the current acceptable ratings of all facilities in the path, from the combiner box to the PV module. In addition, the array line-line fault characteristics include short-circuit current from the solar array and back feed current from the inverter based on the accident point. These accident currents contribute to fire accidents with strong arcs from the short-circuit point.