Damage formation on electrical conductors

Zgradbe našega časa so opremljene z električno napeljavo, katere sestavni del so električni vodniki, le-ti pa so pogosto povezani tudi z nesrečami - požari. Zaradi kompleksnih pogojev prisotnih v požaru – torej med gorenjem različnih materialov nastanejo razmere, ki so lahko za vsak dogodek specifične. Prav zaradi tega, še vedno ni ustaljenih metod za določanje vloge električnih vodnikov (in drugih elementov električnega tokokroga) pri nastanku požara - ali je vodnik povzročitelj ali zgolj ¨žrtev¨ dogodkov. Prav to pa je največja ovira pri določanju izvora poškodb. Obenem pa se sprašujemo ali je vzrok nastanka požara sploh mogoče določiti? Kljub temu, da so vodniki obdani s samougasljivimi ali negorljivimi materiali, lahko pri nekaterih pogojih vseeno pride do vžiga in v skrajnih primerih tudi do požara. Poškodovani deli električne napeljave lahko ob stiku s predmeti predstavljajo močan toplotni vir, ki lahko povzroči vžig materialov v neposredni bližini. Prav tako pa lahko vir toplote (požar) povzroči poškodbe vodnikov. Za boljše razumevanje smo v sklopu diplomske naloge opravili preiskave vodnikov vpletenih v požare in v laboratoriju pripravili primerjalne vzorce poškodovanih žic. S primerjavo rezultatov analize mikrostrukture in kemijske sestave vzorcev vodnikov poškodovanih v požaru, ter vzorcev pripravljenih v laboratoriju bom skušala odgovoriti na vprašanji: zakaj pride do krhkosti pri poškodovanih vodnikih in kaj se pravzaprav dogaja na poškodovanih stikih.Electrical installation is one of key components of Buildings in our time, for that reason electrical conductors are often involved in accidents – house or other fires. Burning of different materials during the course of fire, usually creates unique circumstances. Due to complicated setting of the scene which makes use of standardized tests impossible, we are left with seemingly impossible question. What was the cause of the fire – was electrical conductor (or any other element of electrical installation) at fault or just another ¨victim¨. And yet we still wonder, is it even possible to determinate the cause? Even with modern self-extinguishing and flame-resistant materials, electrical conductors can (in the right conditions) still ignite the fire. Mostly it is due to unprotected wires under voltage which can present a powerful heat source that ignites objects and materials in near vicinity. Fires caused by electrical conductors are often traced back to damaged protective layer. For better understanding of changes in electrical conductors, we compared conductor samples from fires and those damaged in laboratory. With the help of modern technology and it\u27s power of precision while analyzing chemical components and structure of materials I\u27m going to try and answer the following questions: why do electrical conductors involved in fire get fragile and what is happening on damaged contacts