Deals with the selection of equipment and its erection. It provides common rules for compliance with measures of protection for safety, requirements for proper functioning for intended use of the installation, and requirements appropriate to the external influences foreseen. The main changes with respect to the previous edition are listed below: - corrections of misprints in Table 51 based on Table 321 derived from the old Part 3; - introduction of a new Clause 516 dealing with measures for mitigation of protective conductor currents; - introduction of an informative Annex B extracted from IEC 61140 in Annex E of this standard. Annex B of IEC 61140 deals with protective conductor currents.