Abstract: In this paper, an arc grounding short circuit fault caused by the expansion of porcelain insulation pole of 10 kV drop out fuse is analyzed. The fault causes the outgoing line switch of the substation to trip, and at the same time, the high-order harmonic component of the fault voltage is transferred to the low-voltage side through the distribution transformer winding, causing damage to specific single-phase electrical equipment (LED lamps) at the low-voltage side.Therefore, suggestions on improving the legal basis for compensation of household appliances damaged in the failure are proposed.