I choosed for the theme of my thesis the design of the electric system of a more levels building. I learned this part of the electric power engineering in the last summer on my traineeship and it piqued my attendence. The designing I made with Autocad, because this program is very important in the planning of building’s electricity. First I began with significant things like the „cleaning” of the ground plans and I charted the house. I took notice of point of view the architectural and mechanical engineering while I planned the places of main and sub-distributors. After I continued with the design of lighting with Dialux program. With this software could visualize the planned places in 3D. After I had finished this I drew in the circuits fittings taking into accounts the places where we can switch these and the energy saving point of view. I installed other fittings on the layout like thermostat, sockets and fix boundings. The main part of the project are the distributors drawing. I calculated the nominal current from the installed capacity and I defined the protection and cable’s cross sections. I modified these values by the voltage drop if it was neccesary. Than I assigned the closure current and the short circuit protection with Ecodial software. At the end of the thesis I present the electric shock protection of my plan and other important problems which we couldn’t skip by electric system plans. In a few sentences I review a safety house by the fire and lightning point of view and I shall review the uninterruptible power supply systems.