Secondary arcs on solar arrays are a serious threat to the safety of spacecraft operation. Experiments to characterize secondary arcs are currently being conducted. In this study, the effect of external capacitance in the test circuit on the transition from a primary discharge to secondary is investigated. In addition, the effect of flashover current with a long duration of the order of 100 μs is also investigated. The time delay from the inception of the primary discharge to secondary arc formation and the resistance of secondary arc plasma are investigated by analyzing the experimental waveforms. The transition to secondary arc occurs within 10–20 μs from the inception of the primary discharge. The flashover duration does not affect secondary arc occurrence. To maintain a temporary sustained arc, a gap voltage of 30 V can be regarded as the physical threshold for multijunction solar cells. The occurrence of a permanent sustained arc depends on the string current rather than on the energy of the primar...