This project deals about the design of the low voltage electrification of a box factory. The project starts with the list of all the charges of the factory installation. Since here, we starts a connection as only user of a transformer that power all our consume. The transformer doesn’t is included in this project. We design the power lines of the charges since the sub-panels, the lines that power this sub-panels, the sub-panels and the general distribution panel. In the memory are indicated the loads to power, the legal specifications to be followed by each part of the project and includes a summary of all the installation protections, a summary of the lines and a summary of each panel including the short-circuit currents. In the calculations volume, are detailed the procedure followed to dimension the lines and are shown all the results. In the part of planes is included, first the physic planes, that are site, situation and floor planes. Then the volume III have the line diagrams, including information of the lines and the protections. At the end is included a budget that is divided in conductor installation and panel installation.