EN IEC 61558-1:2019
(Main)Safety of transformers, reactors, power supply units and combinations thereof - Part 1: General requirements and tests
General Information
- Abstract
NEW!IEC 61558-1:2017 is available as IEC 61558-1:2017 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition. IEC 61558-1:2017 deals with safety aspects of transformers, reactors, power supply units and combinations thereof such as electrical, thermal and mechanical safety. This document covers the following independent or associated stationary or portable types of dry-type transformers, power supply units, including switch mode power supply units, reactors and combinations thereof in the field of safety. The windings can be encapsulated or non-encapsulated. They are not forming a part of the distribution network. This third edition cancels and replaces the second edition published in 2005 and Amendment 1:2009. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: a. fully insulated winding wires (FIW), new tables and aging tests for FIW constructions, b. overvoltage categories 1, 2, 3 and 4 for clearances and dielectric strength tests (new tables) are included, c. development of new symbols for the different overvoltage categories, d. symbol for maximum altitudes, if higher than 2 000 m, e. symbol for plug in power supply units, if the pins are damaged (tumbling barrel test), f. symbol for minimum temperature (even during the transportation), g. alternative temperature measurement, simulated load and back to back method according to IEC 60076-11, h. short circuit and overload protection, simulated load and back to back method according to IEC 60076-11, i. adjustment of temperatures in Table 2 according to CENELEC Guide 29, j. establishing partial discharge test above 750 V for FIW constructions, k. requirements for toroidal core constructions, division for basic and for supplementary isolation, l. modification of protection indexes for enclosures (IP-code), m. dimensioning of rectangular cross section connectors for transformers, n. repetition test, 80% of required dielectric strength test voltage of Table 14,a. o. vibration test for vehicles and railway applications, p. two Y1 Capacitors for working voltages above 250 V and not exceeding 500 V with overvoltage category 3. It has the status of a group safety publication in accordance with IEC Guide 104.
- Status
- Published
- Publication Date
- 20-Jun-2019
- Withdrawal Date
- 20-Jun-2022
- Technical Committee
- CLC/SR 96 - Small power transformers, reactors, power supply units and similar products
- Drafting Committee
- IEC/TC 96 - IEC_TC_96
- Current Stage
- 9093 - Decision to confirm - Review Enquiry
- Start Date
- 15-Dec-2025
- Completion Date
- 25-Aug-2026
- Directive
- Harmonized Standard2014/35/EU - Directive 2014/35/EU of the European Parliament and of the Council of 26 February 2014 on the harmonisation of the laws of the Member States relating to the making available on the market of electrical equipment designed for use within certain voltage limitsOJ Ref: L 250/, L 250/121 OJ Date: 03-Aug-2020
Overview
EN IEC 61558-1:2019 - Safety of transformers, reactors, power supply units and combinations thereof - Part 1: General requirements and tests is the third-edition, harmonized European version of IEC 61558-1 (edition 2017). It sets general safety requirements and test methods for stationary or portable dry‑type transformers, reactors, switch‑mode and other power supply units, and combinations thereof used for safety-related applications (windings may be encapsulated or non‑encapsulated). This edition replaces EN 61558-1:2005 and its amendment and is a group safety publication in accordance with IEC Guide 104. IEC 61558-1:2017 is also available as IEC 61558-1:2017 RLV (International Standard with redline changes).
Key topics and technical requirements
The standard covers electrical, thermal and mechanical safety and defines tests and markings to demonstrate compliance. Significant technical updates in this edition include:
- Fully Insulated Winding (FIW) provisions: new tables and aging/partial discharge tests for FIW constructions.
- Overvoltage categories (1–4) for clearances and dielectric strength with new symbols.
- Symbols for maximum altitude, minimum temperature (transport) and plug-in PSU pin-damage (tumbling barrel test).
- Alternative temperature measurement and simulated-load/back‑to‑back test methods per IEC 60076‑11.
- Requirements for short‑circuit and overload protection, and repetition dielectric tests (80% voltage).
- Toroidal core construction requirements and differentiation of basic vs supplementary insulation.
- IP-code modifications for enclosures and dimensioning rules for rectangular connectors.
- New mechanical/environmental tests such as vibration tests for vehicle and railway applications.
- Capacitor requirements: two Y1 capacitors for working voltages >250 V ≤500 V with overvoltage category 3.
Practical applications and users
Who uses this standard:
- Manufacturers of transformers, reactors, and power supply units (including SMPS) for design, testing and CE marking.
- Product safety and compliance engineers applying the Low Voltage Directive (LVD) in the EU.
- Test laboratories and conformity assessment bodies performing dielectric, temperature, partial discharge, and mechanical tests.
- System integrators, procurement and specification writers who need guaranteed safety performance for industrial, railway, vehicle and consumer equipment.
Practical value:
- Ensures robust protection against electric shock, fire and mechanical hazards.
- Provides harmonized test methods and symbols to support regulatory acceptance and market access.
- Guides selection of insulation systems, protection devices, enclosure ratings and environmental qualifications.
Related standards
Relevant cross‑references commonly used with EN IEC 61558-1:2019 include IEC 60076-11 (dry‑type transformers), IEC 60664-1 (insulation coordination), IEC 60529 (IP code), and winding wire standards such as IEC 60317 and test methods in IEC 60851.
Keywords: EN IEC 61558-1:2019, safety of transformers, power supply units, reactors, general requirements and tests, IEC 61558-1, FIW, overvoltage categories, partial discharge, IEC 60076-11.
Relations
- Effective Date
- 25-Jun-2019
- Effective Date
- 25-Jun-2019
- Effective Date
- 25-Aug-2026
- Effective Date
- 20-Feb-2026
- Effective Date
- 10-Feb-2026
- Effective Date
- 10-Feb-2026
- Effective Date
- 10-Feb-2026
- Effective Date
- 10-Feb-2026
- Effective Date
- 10-Feb-2026
- Effective Date
- 10-Feb-2026
- Effective Date
- 10-Feb-2026
- Effective Date
- 10-Feb-2026
- Refers
ISO 8820-1:2014 - Road vehicles — Fuse-links — Part 1: Definitions and general test requirements - Effective Date
- 10-Feb-2026
- Effective Date
- 10-Feb-2026
- Effective Date
- 09-Feb-2026
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Frequently Asked Questions
EN IEC 61558-1:2019 is a standard published by CLC. Its full title is "Safety of transformers, reactors, power supply units and combinations thereof - Part 1: General requirements and tests". This standard covers: NEW!IEC 61558-1:2017 is available as IEC 61558-1:2017 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition. IEC 61558-1:2017 deals with safety aspects of transformers, reactors, power supply units and combinations thereof such as electrical, thermal and mechanical safety. This document covers the following independent or associated stationary or portable types of dry-type transformers, power supply units, including switch mode power supply units, reactors and combinations thereof in the field of safety. The windings can be encapsulated or non-encapsulated. They are not forming a part of the distribution network. This third edition cancels and replaces the second edition published in 2005 and Amendment 1:2009. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: a. fully insulated winding wires (FIW), new tables and aging tests for FIW constructions, b. overvoltage categories 1, 2, 3 and 4 for clearances and dielectric strength tests (new tables) are included, c. development of new symbols for the different overvoltage categories, d. symbol for maximum altitudes, if higher than 2 000 m, e. symbol for plug in power supply units, if the pins are damaged (tumbling barrel test), f. symbol for minimum temperature (even during the transportation), g. alternative temperature measurement, simulated load and back to back method according to IEC 60076-11, h. short circuit and overload protection, simulated load and back to back method according to IEC 60076-11, i. adjustment of temperatures in Table 2 according to CENELEC Guide 29, j. establishing partial discharge test above 750 V for FIW constructions, k. requirements for toroidal core constructions, division for basic and for supplementary isolation, l. modification of protection indexes for enclosures (IP-code), m. dimensioning of rectangular cross section connectors for transformers, n. repetition test, 80% of required dielectric strength test voltage of Table 14,a. o. vibration test for vehicles and railway applications, p. two Y1 Capacitors for working voltages above 250 V and not exceeding 500 V with overvoltage category 3. It has the status of a group safety publication in accordance with IEC Guide 104.
NEW!IEC 61558-1:2017 is available as IEC 61558-1:2017 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition. IEC 61558-1:2017 deals with safety aspects of transformers, reactors, power supply units and combinations thereof such as electrical, thermal and mechanical safety. This document covers the following independent or associated stationary or portable types of dry-type transformers, power supply units, including switch mode power supply units, reactors and combinations thereof in the field of safety. The windings can be encapsulated or non-encapsulated. They are not forming a part of the distribution network. This third edition cancels and replaces the second edition published in 2005 and Amendment 1:2009. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: a. fully insulated winding wires (FIW), new tables and aging tests for FIW constructions, b. overvoltage categories 1, 2, 3 and 4 for clearances and dielectric strength tests (new tables) are included, c. development of new symbols for the different overvoltage categories, d. symbol for maximum altitudes, if higher than 2 000 m, e. symbol for plug in power supply units, if the pins are damaged (tumbling barrel test), f. symbol for minimum temperature (even during the transportation), g. alternative temperature measurement, simulated load and back to back method according to IEC 60076-11, h. short circuit and overload protection, simulated load and back to back method according to IEC 60076-11, i. adjustment of temperatures in Table 2 according to CENELEC Guide 29, j. establishing partial discharge test above 750 V for FIW constructions, k. requirements for toroidal core constructions, division for basic and for supplementary isolation, l. modification of protection indexes for enclosures (IP-code), m. dimensioning of rectangular cross section connectors for transformers, n. repetition test, 80% of required dielectric strength test voltage of Table 14,a. o. vibration test for vehicles and railway applications, p. two Y1 Capacitors for working voltages above 250 V and not exceeding 500 V with overvoltage category 3. It has the status of a group safety publication in accordance with IEC Guide 104.
EN IEC 61558-1:2019 is classified under the following ICS (International Classification for Standards) categories: 29.180 - Transformers. Reactors. The ICS classification helps identify the subject area and facilitates finding related standards.
EN IEC 61558-1:2019 has the following relationships with other standards: It is inter standard links to EN 61558-1:2005, EN 61558-1:2005/A1:2009, EN IEC 60127-7:2026, IEC 60906-1:2009, IEC 60884-1:2002/AMD2:2013, IEC 60245-1:2003+AMD1:2007 CSV, IEC 60884-2-4:2007, IEC 60227-1:2007, IEC 60227-5:2011, IEC 60245-4:2011, IEC 60884-1:2002+AMD1:2006 CSV, IEC TR 60083:2015, ISO 8820-1:2014, IEC 60884-1:2002/AMD1:2006, EN ISO 2233:2001. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.
EN IEC 61558-1:2019 is associated with the following European legislation: EU Directives/Regulations: 2014/35/EU; Standardization Mandates: M/511. When a standard is cited in the Official Journal of the European Union, products manufactured in conformity with it benefit from a presumption of conformity with the essential requirements of the corresponding EU directive or regulation.
EN IEC 61558-1:2019 is available in PDF format for immediate download after purchase. The document can be added to your cart and obtained through the secure checkout process. Digital delivery ensures instant access to the complete standard document.