구리 전선의 전기단락흔과 열용융흔의 특성에 관한 연구

Abstract

In order to observe the characteristics of short-circuit traces and heat melting traces when a fire occurs due to electrical causes, the following conclusions were drawn as a result of comparison and analysis through experiments.

1) It was confirmed that the electrical short-circuit tracess (primary short-circuit traces and secondary short-circuit traces) and the thermal melt (third short-circuit traces) can be distinguished through external characteristics and a metal microscope, whereas the primary short-circuit traces due to short-circuit and flame during current flow are not easy to distinguish.

2) As for the external characteristics of the primary short-circuit mark, it may be observed that the end part of the molten net is mostly round, smooth, and glossy, and the surface is rough due to the voide generated when external air is mixed.

3) The boundary between the melted part and the base material part by arc heat could be clearly confirmed, and as for the characteristics of the primary short-circuit mark observed with a metal microscope, it was observed that relatively small and are widely distributed throughout.

4) Columnar tissue and columnar interface extending long in the outer direction of the molten portion were identified.

5) As for the appearance characteristics of the secondary short-circuit mark, the melting part was gentle and soft, similar to the primary short-circuit mark, but the gloss was relatively small.

6) The molten bulb was formed in an elliptical shape, and carbonized impurities were observed between the wires.

7) As the characteristics of the secondary short-circuit traces observed with a metallographic microscope, a larger number of voide were observed compared to the primary short-circuit traces, and the shape of the voide was oval or atypical. and columnar tissue and columnar boundary were confirmed.

8) As for the external characteristics of the tertiary heat fusion trace, the overall melting range is wide and rough, the surface is not glossy, the shape of the molten bulb just before the water droplet is observed at the end of the electric wire, and no voide are observed.

9) The boundary between the melted part and the base material was melted and tapered by heat, characteristics of the tertiary heat melt observed with a metal microscope were significantly smaller than those of no voide or short-circuit traces, and columnar tissue and columnar boundary were not observed, but branch-shaped dendritic structure was observed.

10) In investigating the cause of electric fire, a method of distinguishing between the primary short-circuit mark and the secondary short-circuit mark is important, but a clear distinction is not yet established. However, there must be a difference, and I think the difference between the first and second paragraph traces can be found if manpower and equipment are put in from institutions dealing with electric fires, including firefighting agencies, and continuous comparative analysis through in-depth research and experiments.