The subject of Metallography researches microstructures of different products made from metals and their alloys. The essence of metallographic research of the melted electricity cables consists in studying the microstructure of melted and adjoining to the melted particles of material for the purpose of definition those conditions in which they were formed. In other words, before the fire (and, perhaps, they were its reason) or during the fire (and, perhaps, turned out to be its consequence).

Here you can observe a panoramic image of the microstructure of an electricity copper cable which has been melted by an electric arch, investigated within a judicial fire expertise for the purpose of differentiation conditions of fire-dangerous operating mode of the power supply network. This image is synthesized from 133 micro-photos zoomed more than x800, and made on metallographic microscope, an eyepiece camera and the special software. The reactant applied to etching consists of ferric chloride, hydrochloric acid and the distilled water in ratios: FeCl3 - 5g, HCl (1,19 g/cm3) - 30 ml, H2O – 100 ml.

The studied microstructure has a sharp edge between the melted and not melted parts of an electricity cable that is a clear sign of short circuit. Alloy represents grains of eutectic colonies (Cu-Cu2O) consisting of copper (a light basis) and copper oxide (I) (dark dots). The space occupied by an eutectic is 100%, the content of oxygen is 0,39% (3,4% of Cu2O). There is an insignificant porosity. The alloy is eutectic. In not-melted microstructure of an electricity cable large grains of the recrystallized (annealed) copper with doubles of annealing and the distributed inclusions of Cu2O are observed.