TY JOUR TI Investigation of damage to copper conductors under external thermal influences KW copper KW copper conductors KW fire safety expertise KW metallographic examination KW microstructure KW macrostructure JO Siberian Fire and Rescue Bulletin AU Loran, N.M. AU Chikulaeva, E.M. AU Uglov, A.I. AU Yemelyanov, D.K. AU Volynshchikova, S.A. PY 2026 IS 0 PB FSBEE HE Siberian Fire and Rescue Academy EMERCOM of Russia