Inelastic stretching of a single-wire copper conductor under unlimited local strains at positive temperature

Experimental and theoretical data for strains arising in a single-wire copper conductor experiencing a current load are reported. The conductor has been examined under a JSM-6390L scanning electron microscope. A mathematical model for the stress–strain state of a stretched copper rod at 700$^\circ$C has been developed on the basis of the nonlinear problem of construction mechanics. Mechanical forces that lead to necking in a single-wire copper conductor through which extra current passes have been determined. The mathematical model has been reduced to simple analytical relationships, which can be applied in forensic fire investigation.