BS EN IEC 61558-2-16:2025 - Page 2

Safety of transformers, reactors, power supply units and combinations thereof. Particular requirements and tests for switch mode power supply units and transformers for switch mode power supply units for general applications | Status: Current

1 Scope Replacement This part of IEC 61558 deals with the safety of switch mode power supply units and transformers for switch mode power supply units.

NOTE 1 Safety includes electrical, thermal and mechanical aspects.

Unless otherwise specified, from here onward, the term SMPS covers switch mode power supply units for general applications. SMPS covered by this document are air cooled (natural or forced) independent, associated, stationary, portable, single-phase or polyphase with the rated supply voltage not exceeding 1 000 V AC, the rated supply frequency not exceeding 500 Hz, the rated internal operating frequency exceeding 500 Hz, but not exceeding 100 MHz, and the rated output not exceeding 1 kVA or 1 kW, incorporating dry-type transformers with encapsulated or non-encapsulated windings.

NOTE 2 As the maximum rated supply voltage of the internal transformer is 1 000 V AC, the maximum rated supply voltage of the switch mode power supply unit can be lower due to the type of rectification.

NOTE 3 For higher frequencies, additional requirements can be necessary. However, this document can be used for guidance.

This document is applicable to SMPS, converters and inverters without limitation of the rated output subject to an agreement between the purchaser and the manufacturer.

NOTE 4 In the context of this document, converters and inverters are considered to be SMPS.

This document applies to:

1. a) SMPS incorporating safety isolating transformers providing SELV, PELV, AC or DC output voltage(s) or a combination thereof in accordance with IEC 61140 and IEC 60364‑4‑41 for use with household and other consumer products,
2. b) SMPS with a maximum output voltage not exceeding 1 000 V AC or 1 415 V ripple-free DC for use with household and other consumer products, except for products covered in a),
3. c) This document can be used for transformers for use in SMPS (see Annex BB).

This document does not apply to:

• • motor-generator sets;
• • uninterruptible power supplies (UPS) in accordance with the IEC 62040 series;
• • SMPS covered by IEC 61204‑7 (i.e. low-voltage power supply devices DC output, performance characteristics) and DC power and distribution equipment and SMPS for use in applications covered by IEC 61010‑1 and IEC 60601‑1;
• • lamp control gear covered by the IEC 61347 series;
• • external circuits and their components intended to be connected to the input terminals and output terminals of the SMPS;
• • equipment in accordance with IEC 60065, IEC 60950‑1 and IEC 62368‑1.

This document can also be used for guidance for products not covered by the scope of this document, the scope of IEC 61204‑7 or the scope of the IEC 61347 series. This document covers the safety requirements for:

• • SMPS incorporating separating transformers for general use corresponding to IEC 61558‑2‑1;
• • SMPS incorporating isolating transformers for general use corresponding to IEC 61558‑2‑4;
• • SMPS incorporating safety isolating transformers for general use corresponding to IEC 61558‑2‑6;
• • SMPS incorporating auto-transformers for general use corresponding to IEC 61558‑2‑13.

For SMPS for specific applications corresponding to the other documents of the IEC 61558‑2 series, the necessary requirements of the relevant documents of the IEC 61558‑2 series are applicable. In addition, the requirements listed in this document apply. Where two requirements are in conflict, the more severe takes precedence. The no-load output voltage or the rated output voltage of SMPS does not exceed:

• • 1 000 V AC or 1 415 V ripple-free DC when SMPS incorporating separating transformers or auto-transformers are used;
• • 500 V AC or 708 V ripple-free DC when SMPS incorporating isolating transformers are used;
• • 50 V AC or 120 V ripple-free DC when SMPS incorporating safety isolating transformers is used.

The no-load output voltage or the rated output voltage of independent SMPS is not less than:

• • 50 V AC or 120 V ripple-free DC when separating transformers, isolating transformers or auto-transformers are used.

Attention is drawn to the following:

• • additional requirements for SMPS intended to be used in vehicles, on board ships and aircraft (from other applicable standards, national rules, etc.);
• • measures to protect the enclosure and the components inside the enclosure against external influences such as fungus, vermin, termites, solar-radiation and icing;
• • the different conditions for transportation, storage and operation of the SMPS;
• • additional requirements in accordance with other appropriate standards and national rules can be applicable to SMPS intended for use in special environments.

Future technological development of SMPS can necessitate a need to increase the upper limit of the frequencies. Until then, this document can be used as a guidance document. This group safety publication focusing on safety guidance is primarily intended to be used as a product safety standard for the products mentioned in the scope, but is also intended to be used by TCs in the preparation of publications for products similar to those mentioned in the scope of this group safety publication, in accordance with the principles laid down in IEC Guide 104 and lSO/lEC Guide 51. One of the responsibilities of a TC is, wherever applicable, to make use of BSPs and/or GSPs in the preparation of its publications.