Scope and object This part of IEC 61 204 specifies electromagnetic compatibility (EMC) requirements for power supply units (PSUs) providing d.c. output(s) up to 200 V at a power level of up to 30 kW@ operating from a.c. or d.c. source voltages of up to 600 V. The devices are for free-standing operation or for use in other equipment when used with adequate electrical and mechanical protection. For certain specialized industrial PSUs@ for example in the chemical and metallurgical industry@ other product EMC standards may exist. In this case these standards can be used as an alternative. Since many PSUs are used as components of larger units which are covered by different EMC standards@ a classification of power supplies and the applicability of the relevant EMC standards is given in items a) and b) below. Further guidelines on classification are given in annex A. a) Power supplies intended for free-standing operation (individual apparatus). This part of IEC 61204 is applicable to PSUs developed as a unit with a direct function and sold on the market as a stand-alone unit. b) Component power supplies These can be divided into two categories: 1 ) Component power supplies considered as equivalent to apparatus. This part of IEC 61204 is applicable to this category of component PSUs. These PSUs are considered to be apparatus with respect to their EMC requirements@ for example those PSUs intended for use in installations or sold to the general public@ cases where no further EMC tests are anticipated. This does not include PSUs sold as spares for repair which have been tested as part of an overall equipment. 2) Component power supplies intended for a professional assembler/installer This part of IEC 61204 is applicable to this category of power supplies only as an aid to specify relevant EMC requirements in order that various end product standards may be met. These are component power supplies that are intended for incorporation into a final product by a professional assembler. These products may be sold to a professional assembler or placed on the market for specialized distribution and use. In neither case do they perform in themselves a direct function for the user of an end-product. Further EMC tests of the assembly are assumed. NOTE After incorporation into a final product@ the emission values can be altered (e.g. because of modified earth connections). The object of this part of IEC 61204 is to define EMC limits and test methods for PSUs. It includes limits for electromagnetic emissions which may cause interference to other electronic equipment (e.g. radio receivers@ measuring and computer devices)@ as well as electromagnetic immunity limits for continuous and transient conducted and radiated disturbances including electrostatic discharges. This part of IEC 61 204 defines the minimum electromagnetic compatibility requirements for PSUS. To comply with this part of IEC 61204@ no additional EMC tests are required or necessary beyond those stated here.