• Fire Science and Engineering
• /
• v.31 no.6
• /
• pp.83-90
• /
• 2017

If an overcurrent exceeding the rated value is applied to an electric wire, the temperature of the electric wire increases, and the electric wire covering deteriorates to cause a short circuit. The upper limit temperature of the wire varies according to the magnitude of the overcurrent. When a short circuit occurs at each upper temperature limit, a cooling speed difference occurs during the solidification process due to the temperature difference between the short circuit temperature and the wire surface temperature. At this time, the pattern characteristics of the dendritic structure formed on the molten cross section are different. In this study, the upper temperature limit, which varied according to the overcurrent magnitude, was measured. At the time a short circuit occurred, the second branch spacing (dendrite Arm Spacing : DAS) of the dendrite was analyzed and the numerical value was quantified. The experimental results showed that the upper temperature limit increases with the magnitude of the overcurrent, and that the second branch spacing increases with increasing wire temperature.