General Information

Abstract

This part of IEC 61558 deals with safety aspects of control transformers and power supplies incorporating control transformers such as electrical, thermal and mechanical safety This second edition cancels and replaces the first edition published in 1997. It constitutes a technical revision. The main changes consist of updating this Part 2-2 in accordance with Part 1, edition 2, and adding power supplies to the scope. This Part 2-2 has the status of a group safety publication in accordance with IEC Guide 104.

Status
Published
Publication Date
29-Mar-2007
Withdrawal Date
31-Jan-2010
Drafting Committee
IEC/TC 96 - IEC_TC_96
Parallel Committee
IEC/TC 96 - IEC_TC_96
Current Stage
6060 - Document made available - Publishing
Start Date
30-Mar-2007
Completion Date
30-Mar-2007

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EN 61558-2-2:2007

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Overview

EN 61558-2-2:2007, published by CENELEC, outlines the safety requirements for control transformers and power supplies with incorporated control transformers. As a key part of the EN 61558 series, this standard focuses on electrical, thermal, and mechanical safety aspects. It provides specific requirements in addition to general requirements outlined in EN 61558-1, ensuring that control transformers and their integrated power supplies are designed and tested for reliable and safe operation.

This standard has been updated from previous versions to align with the latest safety, marking, and testing protocols. It applies to a wide range of stationary or portable, single-phase or poly-phase, air-cooled control transformers and associated power supplies with rated voltages up to 1,000 V AC and frequencies up to 500 Hz.

Key Topics

  • Scope and Applicability
    • Covers control transformers and power supplies incorporating control transformers, focusing on electrical, thermal, and mechanical safety.
    • Applies to dry-type, encapsulated or non-encapsulated products used in a variety of applications.
    • Excludes transformers covered by IEC 60076-11.
  • Performance Specifications
    • Maximum rated supply voltage: 1,000 V AC.
    • Maximum operating frequency: 500 Hz.
    • Rated thermal output: up to 25 kVA for single-phase, 40 kVA for poly-phase (unless otherwise agreed).
  • Safety Requirements
    • Protection against electric shock.
    • Insulation standards, including requirements for basic, double, or reinforced insulation.
    • Mechanical strength, construction, and provisions against ingress of dust or moisture.
  • Testing and Marking
    • Requirements for marking ratings (thermal and admissible instantaneous output), voltage, graphical symbols, and supply settings.
    • Describes test protocols for performance under load, no-load, short-circuit, insulation resistance, and more.

Applications

EN 61558-2-2:2007 is essential for manufacturers, designers, and integrators of control transformers and related power supply units. The standard ensures that products:

  • Are suitable for industrial control panels, machine tools, automated systems, and other equipment where control circuits require voltage conversion and electrical isolation.
  • Offer consistent electrical safety, especially where voltages differ from supply networks for operational reasons (signaling, interlocking, control).
  • Can be implemented in both portable and stationary equipment across a wide spectrum of industries, including manufacturing, process automation, and building management systems.
  • Comply with regional and international safety regulations, supporting market access in the European Union and other regions adopting EN standards.

Related Standards

Organizations and professionals working with control transformers and power supplies should be aware of related standards, including:

  • EN 61558-1: Safety requirements for power transformers, power supplies, reactors, and similar products - General requirements and tests.
  • IEC 60076-11: Power transformers - Dry-type transformers (for units outside EN 61558-2-2’s scope).
  • IEC Guide 104: Guidelines for the use and preparation of safety publications.
  • Additional parts of the EN 61558 series covering other specific transformer types and applications.

EN 61558-2-2:2007 remains a key reference for ensuring transformer safety and compliance, supporting reliable operation in diverse electrical environments. Adherence to these requirements enhances product safety, marketability, and alignment with both customer and regulatory demands.

Relations

Effective Date
28-Jan-2023
Effective Date
24-Jan-2023
Effective Date
03-Feb-2026
Effective Date
03-Feb-2026

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Standard

EN 61558-2-2:2007

English language (17 pages)
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Frequently Asked Questions

EN 61558-2-2:2007 is a standard published by CLC. Its full title is "Safety of power transformers, power supplies, reactors and similar products - Part 2-2: Particular requirements and tests for control transformers and power supplies incorporating control transformers". This standard covers: This part of IEC 61558 deals with safety aspects of control transformers and power supplies incorporating control transformers such as electrical, thermal and mechanical safety This second edition cancels and replaces the first edition published in 1997. It constitutes a technical revision. The main changes consist of updating this Part 2-2 in accordance with Part 1, edition 2, and adding power supplies to the scope. This Part 2-2 has the status of a group safety publication in accordance with IEC Guide 104.

This part of IEC 61558 deals with safety aspects of control transformers and power supplies incorporating control transformers such as electrical, thermal and mechanical safety This second edition cancels and replaces the first edition published in 1997. It constitutes a technical revision. The main changes consist of updating this Part 2-2 in accordance with Part 1, edition 2, and adding power supplies to the scope. This Part 2-2 has the status of a group safety publication in accordance with IEC Guide 104.

EN 61558-2-2:2007 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 61558-2-2:2007 has the following relationships with other standards: It is inter standard links to EN 61558-2-2:1998, EN IEC 61558-2-2:2025, EN 60076-11:2004, EN 60598-1:2008. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.

EN 61558-2-2:2007 is associated with the following European legislation: EU Directives/Regulations: 2006/95/EC, 2014/35/EU, 2014/53/EU, 73/23/EEC. 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 61558-2-2:2007 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.

Standards Content (Sample)


2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Safety of power transformers, power supplies, reactors and similar products - Part 2-2: Particular requirements and tests for control transformers and power supplies incorporating control transformersSRGREQLKSécurité des transformateurs, alimentations, bobines d'inductance et produits analogues - Partie 2-2: Regles particulieres et essais pour les transformateurs de commande et les alimentations incorporant les transformateurs de commandeSicherheit von Transformatoren, Netzgeräten, Drosseln und dergleichen - Teil 2-2: Besondere Anforderungen und Prüfungen an Steuertransformatoren und Netzgeräten, die Steuertransformatoren enthaltenTa slovenski standard je istoveten z:EN 61558-2-2:2007SIST EN 61558-2-2:2007en,fr,de29.180Transformatorji. DušilkeTransformers. ReactorsICS:SIST EN 61558-2-2:19991DGRPHãþDSLOVENSKI
STANDARDSIST EN 61558-2-2:200701-december-2007

EUROPEAN STANDARD EN 61558-2-2 NORME EUROPÉENNE
EUROPÄISCHE NORM March 2007
CENELEC European Committee for Electrotechnical Standardization Comité Européen de Normalisation Electrotechnique Europäisches Komitee für Elektrotechnische Normung
Central Secretariat: rue de Stassart 35, B - 1050 Brussels
© 2007 CENELEC -
All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.
Ref. No. EN 61558-2-2:2007 E
ICS 29.180 Supersedes EN 61558-2-2:1998
English version
Safety of power transformers, power supplies,
reactors and similar products -
Part 2-2: Particular requirements and tests for control transformers
and power supplies incorporating control transformers (IEC 61558-2-2:2007)
Sécurité des transformateurs, alimentations, bobines d'inductance
et produits analogues -
Partie 2-2: Règles particulières
et essais pour les transformateurs
de commande et les alimentations incorporant les transformateurs
de commande (CEI 61558-2-2:2007)
Sicherheit von Transformatoren, Netzgeräten, Drosseln und dergleichen - Teil 2-2: Besondere Anforderungen
und Prüfungen an Steuertransformatoren und Netzgeräten,
die Steuertransformatoren enthalten (IEC 61558-2-2:2007)
This European Standard was approved by CENELEC on 2007-02-01. CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CENELEC member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CENELEC member into its own language and notified to the Central Secretariat has the same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Cyprus, the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom.

- 2 - Foreword The text of document 96/253/FDIS, future edition 2 of IEC 61558-2-2, prepared by IEC TC 96, Small power transformers, reactors, power supply units and similar products, was submitted to the IEC-CENELEC parallel vote and was approved by CENELEC as EN 61558-2-2 on 2007-02-01. This European Standard supersedes EN 61558-2-2:1998 + corrigendum February 1998. The main changes consist of updating this Part 2-2 in accordance with EN 61558-1:2005, and adding power supplies to the scope. This Part 2-2 is intended to be used in conjunction with the latest edition of EN 61558-1 and its amendments. It is based on EN 61558-1:2005. This Part 2-2 supplements or modifies the corresponding clauses in EN 61558-1, so as to convert that publication into the European standard: Particular requirements and tests for control transformers and power supplies incorporating control transformers. Where a particular subclause of Part 1 is not mentioned in this Part 2-2, that subclause applies as far as is reasonable. Where this Part 2-2 states "addition", "modification" or "replacement", the relevant text of Part 1 is to be adapted accordingly. The following dates were fixed: – latest date by which the EN has to be implemented
at national level by publication of an identical
national standard or by endorsement
(dop)
2007-11-01 – latest date by which the national standards conflicting
with the EN have to be withdrawn
(dow)
2010-02-01 In this Part 2-2, the following print types are used: – requirements proper: in roman type; – test specifications: in italic type; – explanatory matter: in smaller roman type. In the text of this Part 2-2, the words in bold are defined in Clause 3. Subclauses additional to those in Part 1 are numbered starting from 101; supplementary annexes are entitled AA, BB, etc. Annex ZA has been added by CENELEC. __________ Endorsement notice The text of the International Standard IEC 61558-2-2:2007 was approved by CENELEC as a European Standard without any modification. __________

- 3 - EN 61558-2-2:2007
Annex ZA (normative)
Normative references to international publications with their corresponding European publications
Addition: Publication Year Title EN/HD Year IEC 60076-11 - 1) Power transformers -
Part 11: Dry-type transformers EN 60076-11 2004 2)
1) Undated reference.
2) Valid edition at date of issue.

NORME INTERNATIONALE CEIIEC INTERNATIONAL STANDARD 61558-2-2Deuxième éditionSecond edition2007-01 Sécurité des transformateurs, alimentations, bobines d'inductance et produits analogues – Partie 2-2: Règles particulières et essais
pour les transformateurs de commande
et les alimentations incorporant
les transformateurs de commande
Safety of power transformers, power supplies, reactors and similar products – Part 2-2: Particular requirements and tests for
control transformers and power supplies incorporating control transformers
Pour prix, voir catalogue en vigueur For price, see current catalogue© IEC 2007
Droits de reproduction réservés

Copyright - all rights reserved Aucune partie de cette publication ne peut être reproduite ni utilisée sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique, y compris la photo-copie et les microfilms, sans l'accord écrit de l'éditeur. No part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from the publisher. International Electrotechnical Commission,
3, rue de Varembé, PO Box 131, CH-1211 Geneva 20, SwitzerlandTelephone: +41 22 919 02 11 Telefax: +41 22 919 03 00 E-mail: inmail@iec.ch
Web: www.iec.ch Commission Electrotechnique InternationaleInternational Electrotechnical CommissionN CODE PRIX PRICE CODE PUBLICATION GROUPÉE DE SÉCURITÉ
GROUP SAFETY PUBLICATION
61558-2-2 © IEC:2007 – 3 –
CONTENTS FOREWORD.5
1 Scope.9 2 Normative references.11 3 Terms and definitions.11 4 General requirements.13 5 General notes on tests.13 6 Ratings.13 7 Classification.15 8 Marking and other information.15 9 Protection against electric shock.17 10 Change of input voltage setting.17 11 Output voltage and output current under load.17 12 No-load output voltage.19 13 Short-circuit voltage.19 14 Heating.19 15 Short-circuit and overload protection.21 16 Mechanical strength.21 17 Protection against harmful ingress of dust, solid objects and moisture.21 18 Insulation resistance, dielectric strength and leakage current.21 19 Construction.21 20 Components.23 21 Internal wiring.23 22 Supply connection and other external flexible cables or cords.23 23 Terminals for external conductors.25 24 Provisions for protective earthing.25 25 Screws and connections.25 26 Creepage distances, clearances and distances through insulation.25 27 Resistance to heat, fire and tracking.25 28 Resistance to rusting.25
Annexes.27

61558-2-2 © IEC:2007 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION ___________
SAFETY OF POWER TRANSFORMERS, POWER SUPPLIES,
REACTORS AND SIMILAR PRODUCTS –
Part 2-2: Particular requirements and tests
for control transformers and power supplies
incorporating control transformers
FOREWORD 1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and in addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with may participate in this preparatory work. International, governmental and non-governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely with the International Organization for Standardization (ISO) in accordance with conditions determined by agreement between the two organizations. 2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international consensus of opinion on the relevant subjects since each technical committee has representation from all interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any misinterpretation by any end user. 4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications transparently to the maximum extent possible in their national and regional publications. Any divergence between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter. 5) IEC provides no marking procedure to indicate its approval and cannot be rendered responsible for any equipment declared to be in conformity with an IEC Publication. 6) All users should ensure that they have the latest edition of this publication. 7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and members of its technical committees and IEC National Committees for any personal injury, property damage or other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is indispensable for the correct application of this publication. 9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent rights. IEC shall not be held responsible for identifying any or all such patent rights. International standard IEC 61558-2-1 has been prepared by IEC technical committee 96: Small power transformers, reactors, power supply units and similar products. This second edition cancels and replaces the first edition published in 1997. It constitutes a technical revision. The main changes consist of updating this Part 2-2 in accordance with Part 1, edition 2, and adding power supplies to the scope. This Part 2-2 has the status of a group safety publication in accordance with IEC Guide 104: The preparation of safety publications and the use of basic safety publications and group safety publications (1997).

61558-2-2 © IEC:2007 – 7 –
The text of this standard is based on the following documents: FDIS Report on voting 96/253/FDIS 96/266/RVD
Full information on the voting for the approval of this standard can be found in the report on voting indicated in the above table. This publication has been drafted in accordance with the ISO/IEC Directives, Part 2. This Part 2-2 is intended to be used in conjunction with the last edition of IEC 61558-1 and its amendments. It is based on the second edition (2005) of that standard. This Part 2-2 supplements or modifies the corresponding clauses in IEC 61558-1, so as to convert that publication into the IEC standard: Particular requirements and tests for control transformers and power supplies incorporating control transformers. A list of all parts of the IEC 61558 series, under the general title: Safety of power transformers, power supplies, reactors and similar products, can be found on the IEC website. Where a particular subclause of Part 1 is not mentioned in this Part 2-2, that subclause applies as far as is reasonable. Where this Part 2-2 states "addition", "modification" or "replacement", the relevant text of Part 1 is to be adapted accordingly. In this Part 2-2, the following print types are used: – requirements proper: in roman type; – test specifications: in italic type; – explanatory matter: in
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