Abstract
The article discusses the principles of electrical circuits formation and includes analysis, which showed that two-way feed ring and trunk networks are the most promising and efficient in technical and economic terms. It has also been found that, currently, in a closed configuration network in the normal operating mode of a network with two power sources, one of the lines must be disconnected. This is due to the impossibility to selectively trip a damaged line, in particular, with single phase-to-earth fault (SEF). It describes that the SEF is the main type of electrical damage in 6-10 kV cable networks.