IEC 61558-2-7:2023
(Main)Safety of transformers, reactors, power supply units and combinations thereof - Part 2-7: Particular requirements and tests for transformers and power supply units for toys
Safety of transformers, reactors, power supply units and combinations thereof - Part 2-7: Particular requirements and tests for transformers and power supply units for toys
IEC 61558-2-7:2023 is available as IEC 61558-2-7:2023 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition.
IEC 61558-2-7:2023 deals with the safety of transformers for toys and power supply units incorporating transformers for toys. Transformers for toys incorporating electronic circuits are also covered by this document. This third edition cancels and replaces the second edition published in 2007. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition:
a) adjustment of structure and references in accordance with IEC 61558-1:2017;
b) new symbol for power supply unit with linearly regulated output voltage.
It has the status of a group safety publication in accordance with IEC Guide 104.
Sécurité des transformateurs, bobines d'inductance, blocs d'alimentation et des combinaisons de ces éléments – Partie 2-7: Exigences particulières et essais pour les transformateurs et blocs d'alimentation pour jouets
IEC 61558-2-7:2023 est disponible sous forme de IEC 61558-2-7:2023 RLV qui contient la Norme internationale et sa version Redline, illustrant les modifications du contenu technique depuis l'édition précédente.
L'IEC 61558-2-7:2023 traite de la sécurité des transformateurs pour jouets et des blocs d'alimentation qui incorporent des transformateurs pour jouets. Les transformateurs pour jouets qui incorporent des circuits électroniques sont également couverts par le présent document. Cette troisième édition annule et remplace la deuxième édition parue en 2007. Cette édition constitue une révision technique. Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente:
a) la structure et les références ont été alignées sur l'IEC 61558-1:2017;
b) un nouveau symbole a été ajouté pour les blocs d'alimentation dont la régulation de la tension secondaire est linéaire.
Il a le statut de publication groupée de sécurité conformément au Guide 104 de l'IEC.
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IEC 61558-2-7 ®
Edition 3.0 2023-06
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
GROUP SAFETY PUBLICATION
Safety of power transformers, power supplies reactors, and similar products
power supply units and combinations thereof –
Part 2-7: Particular requirements and tests for transformers and power supplies
supply units for toys
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form
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About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.
About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
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IEC 61558-2-7 ®
Edition 3.0 2023-06
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
GROUP SAFETY PUBLICATION
Safety of power transformers, power supplies reactors, and similar products
power supply units and combinations thereof –
Part 2-7: Particular requirements and tests for transformers and power supplies
supply units for toys
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.180 ISBN 978-2-8322-7167-4
– 2 – IEC 61558-2-7:2023 RLV IEC 2023
CONTENTS
FOREWORD . 3
INTRODUCTION . 2
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 9
4 General requirements . 9
5 General notes on tests . 10
6 Ratings . 10
7 Classification . 10
8 Marking and other information . 11
9 Protection against electric shock . 12
10 Change of input voltage setting . 12
11 Output voltage and output current under load . 14
12 No-load output voltage . 14
13 Short-circuit voltage . 14
14 Heating . 15
15 Short circuit and overload protection. 15
16 Mechanical strength . 16
17 Protection against harmful ingress of dust, solid objects and moisture . 17
18 Insulation resistance, dielectric strength and leakage current . 17
19 Construction . 17
20 Components . 19
21 Internal wiring . 20
22 Supply connection and other external flexible cables or cords . 20
23 Terminals for external conductors . 21
24 Provisions for protective earthing. 21
25 Screws and connections . 21
26 Creepage distances, clearances and distances through insulation . 21
27 Resistance to heat, abnormal heat, fire and tracking . 21
28 Resistance to rusting . 21
Annexes . 22
Bibliography . 23
Figure 101 – Small test finger . 13
Figure 102 – Arrangement for impact test for transformers (see 16.101) . 16
Table 101 – Symbols indicating the kind of transformer . 11
Table 2 – Values of maximum temperatures in normal use . 15
Table 5 – Maximum values of temperatures under short-circuit or overload conditions . 15
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
SAFETY OF POWER TRANSFORMERS, POWER SUPPLIES
REACTORS, AND SIMILAR PRODUCTS POWER SUPPLY UNITS AND
COMBINATIONS THEREOF –
Part 2-7: Particular requirements and tests for
transformers and power supplies supply units for toys
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 itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
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.
This redline version of the official IEC Standard allows the user to identify the changes
made to the previous edition IEC 61558-2-7:2007. A vertical bar appears in the margin
wherever a change has been made. Additions are in green text, deletions are in
strikethrough red text.
– 4 – IEC 61558-2-7:2023 RLV IEC 2023
IEC 61558-2-7 has been prepared by IEC technical committee 96: Transformers, reactors,
power supply units and combinations thereof. It is an International Standard.
This third edition cancels and replaces the second edition published in 2007. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) adjustment of structure and references in accordance with IEC 61558-1:2017;
b) new symbol for power supply unit with linearly regulated output voltage.
The text of this International Standard is based on the following documents:
Draft Report on voting
96/579/FDIS 96/581/RVD
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/publications.
It has the status of a group safety publication in accordance with IEC Guide 104.
This International Standard is to be used in conjunction with IEC 61558-1:2017.
This document supplements or modifies the corresponding clauses in IEC 61558-1:2017, so as
to convert that publication into the IEC standard: Particular requirements and tests for
transformers and power supply units for toys.
A list of all parts in the IEC 61558 series published under the general title Safety of
transformers, reactors, power supply units and combinations thereof, can be found on the
IEC website.
Future standards in this series will carry the new general title as cited above. Titles of existing
standards in this series will be updated at the time of the next edition.
Where this document states "addition", "modification" or "replacement", the relevant text of
IEC 61558-1:2017 is to be adopted accordingly.
In this document, 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 document, the words in bold are defined in Clause 3.
Subclauses, notes, figures and tables additional to those in IEC 61558-1:2017 are numbered
starting from 101; supplementary annexes are entitled AA, BB, etc.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in
...
IEC 61558-2-7 EXV ®
Edition 3.0 2023-06
EXTENDED VERSION
INTERNATIONAL
STANDARD
colour
inside
This extended version of IEC 61558-2-7:2023 includes the content of the references made to
IEC 61558-1:2017
GROUP SAFETY PUBLICATION
Safety of transformers, reactors, power supply units and combinations thereof –
Part 2-7: Particular requirements and tests for transformers and power supply
units for toys
All rights reserved. Unless otherwise specified, 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
either IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC
copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or
your local IEC member National Committee for further information.
IEC Secretariat Tel.: +41 22 919 02 11
3, rue de Varembé info@iec.ch
CH-1211 Geneva 20 www.iec.ch
Switzerland
About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.
About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigendum or an amendment might have been published.
IEC publications search - webstore.iec.ch/advsearchform IEC Products & Services Portal - products.iec.ch
The advanced search enables to find IEC publications by a Discover our powerful search engine and read freely all the
variety of criteria (reference number, text, technical publications previews. With a subscription you will always have
committee, …). It also gives information on projects, replaced access to up to date content tailored to your needs.
and withdrawn publications.
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IEC Just Published - webstore.iec.ch/justpublished
The world's leading online dictionary on electrotechnology,
Stay up to date on all new IEC publications. Just Published
containing more than 22 300 terminological entries in English
details all new publications released. Available online and once
and French, with equivalent terms in 19 additional languages.
a month by email.
Also known as the International Electrotechnical Vocabulary
(IEV) online.
IEC Customer Service Centre - webstore.iec.ch/csc
If you wish to give us your feedback on this publication or need
further assistance, please contact the Customer Service
Centre: sales@iec.ch.
IEC 61558-2-7 EXV ®
Edition 3.0 2023-06
EXTENDED VERSION
INTERNATIONAL
STANDARD
colour
inside
This extended version of IEC 61558-2-7:2023 includes the content of the references made to
IEC 61558-1:2017
GROUP SAFETY PUBLICATION
Safety of transformers, reactors, power supply units and combinations thereof –
Part 2-7: Particular requirements and tests for transformers and power supply
units for toys
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 29.180 ISBN 978-2-8322-7168-1
– 2 – IEC 61558-2-7:2023 EXV IEC 2023
CONTENTS
FOREWORD . 9
INTRODUCTION TO IEC 61558-1:2017 . 12
INTRODUCTION . 15
1 Scope . 16
2 Normative references . 17
3 Terms and definitions . 20
3.1 Transformers . 20
3.2 General terms . 24
3.3 Operations and protections . 25
3.4 Circuits and windings . 27
3.5 Ratings . 28
3.6 No-load values . 30
3.7 Insulation . 30
3.8 Touch current and protective earthing conductor current . 34
4 General requirements . 34
5 General notes on tests . 34
6 Ratings . 37
7 Classification . 37
8 Marking and other information . 38
9 Protection against electric shock . 44
9.1 General . 44
9.2 Protection against contact with hazardous-live-parts . 45
9.2.1 Determination of hazardous-live-parts . 45
9.2.2 Accessibility to hazardous-live-parts . 45
9.2.3 Accessibility to non hazardous-live-part . 48
9.3 Protection against hazardous electrical discharge . 48
10 Change of input voltage setting . 49
11 Output voltage and output current under load . 49
12 No-load output voltage . 50
13 Short-circuit voltage . 51
14 Heating . 51
14.1 General requirements . 51
14.1.1 Temperature-rise test . 51
14.1.2 Alternative temperature-rise test . 53
14.1.3 Determination of steady-state conditions . 56
14.2 Application of 14.1 or 14.3 according to the insulation system. 58
14.3 Accelerated ageing test for undeclared class of insulation system . 59
14.3.1 General . 59
14.3.2 Heat run . 59
14.3.3 Vibration . 59
14.3.4 Moisture treatment . 60
14.3.5 Measurements . 60
15 Short circuit and overload protection. 60
15.1 General requirements . 60
15.1.1 Short circuit and overload test method . 60
15.1.2 Alternative short circuit and overload test method . 62
15.2 Inherently short-circuit proof transformers . 62
15.3 Non-inherently short-circuit proof transformers. 62
15.4 Non-short-circuit proof transformers . 64
15.5 Fail-safe transformers . 64
16 Mechanical strength . 65
16.1 General . 65
16.2 Stationary transformers . 66
16.3 Portable transformers (except portable transformers with integral pins for
introduction in socket-outlet in the fixed wiring) . 66
16.4 Portable transformers provided with integral pins for introduction in socket-
outlets of the fixed wiring . 66
16.4.1 General requirements . 66
16.4.2 Portable transformers provided with integral pins according to EN
50075 (IEC plug type C) for introduction in socket-outlets of the fixed
wiring . 67
16.5 Additional requirements for transformers to be used in vehicles and railway
applications . 68
16.5.1 Transformers to be used in vehicles and railway applications . 68
16.5.2 Test requirements for the transportation of transformers . 69
17 Protection against harmful ingress of dust, solid objects and moisture . 71
17.1 Degrees of protection provided by enclosures (IP code) . 71
17.1.1 General requirements . 71
17.1.2 Tests on transformers with enclosure . 72
17.2 Humidity treatment . 74
18 Insulation resistance, dielectric strength and leakage current . 75
18.1 General . 75
18.2 Insulation resistance . 75
18.3 Dielectric strength test . 75
18.4 Insulation between and within windings . 77
18.5 Touch current and protective earthing conductor current . 77
18.5.1 General . 77
18.5.2 Touch current . 78
18.5.3 Protective earthing conductor current . 79
19 Construction . 80
19.1 General construction . 80
19.2 Flammability of materials . 80
19.3 Short-circuit characteristics of portable transformers . 80
19.4 Class II transformer contact prevention of accessible conductive parts . 80
19.5 Class II transformer insulation reassembling after service . 81
19.6 Loosening of wires, screws or similar parts . 81
19.7 Resistor or capacitor connection with accessible conductive parts . 81
19.8 Bridging of separated conductive parts by resistors or capacitors . 82
19.9 Insulating material separating input and output windings . 82
19.10 Accidental contact protection against hazardous-live-parts provided by
isolating coating . 83
19.11 Insulating material of handles, operating levers, knobs and similar parts. 84
19.12 Winding construction . 84
19.13 Fixing of handles, operating levers and similar parts . 88
19.14 Fixing of covers providing protection against electric shock . 88
– 4 – IEC 61558-2-7:2023 EXV IEC 2023
19.15 Strain on fixed socket-outlets caused by pin-transformers connection . 88
...
IEC 61558-2-7 ®
Edition 3.0 2023-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
GROUP SAFETY PUBLICATION
PUBLICATION GROUPÉE DE SÉCURITÉ
Safety of transformers, reactors, power supply units and combinations thereof –
Part 2-7: Particular requirements and tests for transformers and power supply
units for toys
Sécurité des transformateurs, bobines d'inductance, blocs d'alimentation et des
combinaisons de ces éléments –
Partie 2-7: Exigences particulières et essais pour les transformateurs et blocs
d'alimentation pour jouets
All rights reserved. Unless otherwise specified, 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
either IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC
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Switzerland
About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.
About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigendum or an amendment might have been published.
IEC publications search - webstore.iec.ch/advsearchform IEC Products & Services Portal - products.iec.ch
The advanced search enables to find IEC publications by a Discover our powerful search engine and read freely all the
variety of criteria (reference number, text, technical publications previews. With a subscription you will always have
committee, …). It also gives information on projects, replaced access to up to date content tailored to your needs.
and withdrawn publications.
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The world's leading online dictionary on electrotechnology,
Stay up to date on all new IEC publications. Just Published
containing more than 22 300 terminological entries in English
details all new publications released. Available online and once
and French, with equivalent terms in 19 additional languages.
a month by email.
Also known as the International Electrotechnical Vocabulary
(IEV) online.
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IEC 61558-2-7 ®
Edition 3.0 2023-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
GROUP SAFETY PUBLICATION
PUBLICATION GROUPÉE DE SÉCURITÉ
Safety of transformers, reactors, power supply units and combinations thereof –
Part 2-7: Particular requirements and tests for transformers and power supply
units for toys
Sécurité des transformateurs, bobines d'inductance, blocs d'alimentation et des
combinaisons de ces éléments –
Partie 2-7: Exigences particulières et essais pour les transformateurs et blocs
d'alimentation pour jouets
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.180 ISBN 978-2-8322-7089-9
– 2 – IEC 61558-2-7:2023 IEC 2023
CONTENTS
FOREWORD . 3
INTRODUCTION . 5
1 Scope . 6
2 Normative references . 7
3 Terms and definitions . 7
4 General requirements . 8
5 General notes on tests . 8
6 Ratings . 8
7 Classification . 8
8 Marking and other information . 9
9 Protection against electric shock . 10
10 Change of input voltage setting . 11
11 Output voltage and output current under load . 11
12 No-load output voltage . 12
13 Short-circuit voltage . 12
14 Heating . 12
15 Short circuit and overload protection. 13
16 Mechanical strength . 14
17 Protection against harmful ingress of dust, solid objects and moisture . 15
18 Insulation resistance, dielectric strength and leakage current . 15
19 Construction . 15
20 Components . 17
21 Internal wiring . 18
22 Supply connection and other external flexible cable or cords . 18
23 Terminals for external conductors . 19
24 Provisions for protective earthing. 19
25 Screws and connections . 19
26 Creepage distances, clearances and distances through insulation . 19
27 Resistance to heat, fire and tracking . 19
28 Resistance to rusting . 19
Annexes . 20
Bibliography . 21
Figure 101 – Small test finger . 11
Figure 102 – Arrangement for impact test for transformers (see 16.101) . 14
Table 101 – Symbols indicating the kind of transformer . 10
Table 2 – Values of maximum temperatures in normal use . 13
Table 5 – Maximum values of temperatures under short-circuit or overload conditions . 13
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
SAFETY OF TRANSFORMERS, REACTORS,
POWER SUPPLY UNITS AND COMBINATIONS THEREOF –
Part 2-7: Particular requirements and tests for
transformers and power supply units for toys
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 itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
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.
IEC 61558-2-7 has been prepared by IEC technical committee 96: Transformers, reactors,
power supply units and combinations thereof. It is an International Standard.
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