BS EN IEC 61204-3:2018

This standard BS EN IEC 61204-3:2018 Low-voltage switch mode power supplies is classified in these ICS categories:

• 33.100 Electromagnetic compatibility (EMC)
• 29.200 Rectifiers. Converters. Stabilized power supply

1.1.1 Equipment covered by this document

This part of IEC 61204 specifies the electromagnetic compatibility (EMC) requirements for switch mode power supply (SMPS) units supplied by source voltages up to 1 000 V AC or 1 500 V DC providing AC and/or DC output(s), except inverter output(s) establishing AC mains (see exceptions under 1.1.3.)

This product standard covers both stand alone and component power supply (PSU) units as defined in this document. It covers PSU units for use in or with IT equipment normally covered by IEC 60950‑1 and/or IEC 62368‑1 ; PSU units for use in or with measurement, control and laboratory equipment normally covered by IEC 61010‑1 ; PSU units for use in or with medical equipment — normally covered by IEC 60601‑1 ; PSU units for use in or with audio, video and similar electronic apparatus — normally covered by IEC 60065 and/or IEC 62368‑1 . It also covers DC power and distribution equipment and DC/DC converters.

Where no standard exist, use of this document for other applications is not precluded.

1.1.2 Additional requirements

Requirements additional to those specified in this document may be necessary for

• PSUs intended for operation in special environments (for example, extremes of temperature; excessive dust, moisture or vibration; flammable gases; and corrosive or explosive atmospheres);

• PSUs intended to be used in vehicles, on board ships or aircraft, or in tropical countries;

• PSUs intended for use where ingress of water is possible.

1.1.3 Exclusions

This document does not apply to

• motor-generator sets;

• uninterruptible power supplies (UPS) to IEC 62040‑1 ;

• PSUs covered by IEC 61558‑1 (i.e. power supply units incorporating safety isolating transformers providing SELV or PELV output(s) in accordance with IEC 60364‑4‑41 ) and PSUs for use with household and other consumer products, except those covered by IEC 60065 and IEC 60950‑1 and/or IEC 62368‑1 ;

• transformers covered by IEC 61558‑1 ;

• step-down converters covered by IEC 60146‑1‑1 ;

• PSUs and converters intended for DC supplied bulb lamps, halogen lamps or LED lamps covered by CISPR 15 .

1.1.4 Types of power supply

Two types of power supplies are covered by this document:

1. stand alone (or end-product) power supplies

   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.

2. component power supplies

   These can be divided into two categories:

   1. component power supplies considered as equivalent to stand alone power supplies (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 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 installer. These products may be sold to a professional installer or placed on the market for specialized distribution and use. Further EMC tests of the assembly are assumed.

1.1.5 Configurations and combinations of power supplies

1.1.5.1 Modular PSUs

A PSU with a single primary circuit or module and separate output modules forming a single unit, synchronized or not, meets the requirements defined in this document as a single component or apparatus type of PSU.

1.1.5.2 Power supply systems

An easily relocatable system containing several PSUs in parallel, in series or combination with a single input connection complies with this document as a single component or apparatus type of PSU. It is the responsibility of the system supplier to ensure EMC compliance with this document or with a specific EMC standard of the end product.

1.1.5.3 Power supply installations

When a number of PSUs are used in an installation and are supplied by a distributed AC or DC network, then this is a power installation. This type of arrangement is not easily relocatable. Each individual PSU complies with this document and this is the responsibility of the PSU manufacturer who also provides information on the correct installation of his product. The EMC considerations of the final installation are the responsibility of the professional installer.

1.1.5.4 Distributed power supplies

This is a power installation where the input AC or DC supply is distributed to individual power conversion units or modules which are installed locally to the circuitry to be supplied. This document applies to the individual products as appropriate. The EMC performance of the overall system or installation is the responsibility of the professional installer.

1.1.5.5 Power supplies in parallel or in series

Where PSUs are sold to be connected in parallel or in series, their documentation shall include information relating to the expected EMC performance for such arrangements.