Influence of resistance of contact units of switching devices on the electric power losses in shop networks of low tensionD. D. Micu, I. V. Ivshin, E. I. Gracheva, O. V. Naumov and A. N. GorlovE3S Web Conf., 124 (2019) 02013DOI: https://doi.org/10.1051/e3sconf/201912402013