Surface Morphology Analysis on Overload Residue of More Strands Copper Wire

The integrated experimental system of material evidence for fire trace was used to make residue of the more strands copper wire under different overcurrent.The surface morphologies of the wire were observed and analyzed by the digital camera and scanning electron microscope.The results indicated that with the increase of overcurrent the insulating cover from softening, bulge, ebullition, melting, carbonization to disengage with core wire. The surface oxidation of core wire becomed serious. The grooved processing nicks becomed no conspicuous, and the core wire surface presented metal melting flowed trace. Therefore, using digital camera and scanning electron microscope to observe and analyze the character of the surface morphology of the more strands copper wire can identify whether it is overloaded and the degree of overload.