Application of wire annealing tester in the study of plastic deformation of copper conductors subjected to current overloading

The article considers the results of the study of copper conductors subjected to current overloads by the method of determining the bending force. It is established that for conductors subjected to current overload with multiplicity from 2.8 to 13, the value of bending force is from 0.6 to 1.16 kg, which is 2-6 times less than for the conductor not subjected to current overload (2.3-2.4 kg). Conductors subjected to current overloads are characterised by the presence of areas where recrystallisation processes have not yet been completed and areas where copper is in a "post-recrystallisation" state. The authors have proposed a mechanism of research with the help of wire annealing tester TOP-01-EP of copper stranded conductors, subjected to current overloads, taken from fire scenes. The criterion of application of the TOP-01-EP wire annealing tester is the simultaneous presence of conductors in the initial ("pre-recrystallisation") state and conductors in which recrystallisation processes are practically completed, i.e. conductors, the value of bending force for which will differ by 2 and more times.