This paper deals with the issue of the fire occurrence which is caused by low-voltage electrical installations (household distribution board) due to the absence of protective devices (fuses and surge arresters) on the pillars of the electrical distribution network. The example of calculation of fault currents is given, for the fault current on the basis of which it is proved the necessity of installing of pole mounted fuse on the latest pillar of low-voltage electrical distribution network. In the paper there are examples of fire expertise for fires caused by non-installation of pole mounted fuses and surge arresters are presented. Key words:atmospheric discharges, over-voltages, fault current, fire, pole mounted fuse, surge arrester