Abstract: Abstract: In view of the frequent fire caused by low-voltage arcs and unclear ignition mechanism, simulate the poor contact fault with the multiple electrical fire causes and prevention device, and study the influence of system power and power factor and carbon electrode diameter on the ignition ability of low-voltage poor contact arcs. The results show that when the system power is no more than 320 W, the paper filter only turns yellow and being carbonized. When the system power is more than 370 W, the paper filter starts to be ignited, and the ignition probability increases with the increase of the system power, and when the power is no less than 480 W, the paper filter can be ignited; the power of the arc decreases with the decrease of the power factor under the experimental conditions; the influence of the diameter on the ignition ability of the arc mainly depends on the size of the anode spot, when the anode spot is larger than the diameter of the carbon electrode, the paper filter can be ignited; on the contrary, the paper filter can hardly be ignited. The research results provide certain basic parameters and theoretical basis for the fire prevention of low-voltage electricity use and the prevention of electrical faults.

Key words: Key words: fault arc, ignition capability, power factor, zero crossing, anode spot