Low-voltage networks are networks with a nominal voltage lower than 1 kV and without exception belong to distribution networks. Low-voltage networks are the most widespread part of the power system. There is almost no settlement, village or hamlet in the developed part of the world that does not have an electric grid. The task of low-voltage networks is to provide all consumers connected to them with a high-quality supply of electricity and to ensure the protection of consumers from direct and indirect contact with live devices, especially in the event of malfunctions. In this final paper, a detailed analysis of the calculation of the low-voltage electrical network TS 20(10)/0.4 kV Marusinac 3 is described and carried out using the WINDis software package. The possibilities of the WINDis program package are briefly described in the second chapter. In the third and fourth chapters, the current and planned state of the electrical network is presented. Formulas are given for calculating short-circuit currents, which are necessary for the correct selection of fuses that will protect the network from overload. In the last chapter, a detailed analysis of the low-voltage network TS 20(10)/0.4 kV Marusinac 3 was carried out in the program package WINDis for each extract, while adhering to the prescribed electric power norms and prescribed standards.