EN IEC 61558-2-10:2024

Safety of transformers, reactors, power supply units and combinations thereof - Part 2-10: Particular requirements and tests for separating transformers with high insulation level and separating transformers with output voltages exceeding 1 000 V

IEC 61558-2-10:2024 is available as IEC 61558-2-10:2024 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition. IEC 61558-2-10:2024 deals with the safety of separating transformers with high insulation level and separating transformers with output voltages exceeding 1 000 V. Transformers incorporating electronic circuits are also covered by this document. This second edition cancels and replaces the first edition published in 2014. 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) overvoltage categories I, II, III and IV for clearances and dielectric strength tests are included; c) clearances for homogenous field conditions deleted. It has the status of a group safety publication in accordance with IEC Guide 104.

Sicherheit von Transformatoren, Drosseln, Netzgeräten und entsprechenden Kombinationen - Teil 2-10: Besondere Anforderungen und Prüfungen für Netztransformatoren mit hohem Isolationspegel und Netztransformatoren mit Ausgangsspannungen über 1 000 V

Sécurité des transformateurs, bobines d'inductance, blocs d'alimentation et des combinaisons de ces éléments - Partie 2-10 : Exigences particulières et essais pour les transformateurs d'isolement à enroulements séparés à niveau d'isolement élevé et pour les transformateurs d'isolement à enroulements séparés à tensions secondaires supérieures à 1 000 V

L'IEC 61558-2-10:2024 est disponible sous forme de IEC 61558-2-10:2024 RLV qui contient la Norme internationale et sa version Redline, illustrant les modifications du contenu technique depuis l'édition précédente. L'IEC 61558-2-10:2024 traite de la sécurité des transformateurs d'isolement à enroulements séparés à niveau d'isolement élevé et des transformateurs d'isolement à enroulements séparés à tensions secondaires supérieures à 1 000 V. Les transformateurs qui incorporent des circuits électroniques sont également couverts par le présent document. Cette seconde édition annule et remplace la première édition parue en 2014. 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) les catégories de surtension I, II, III et IV pour les essais de rigidité diélectrique et les distances d'isolement ont été ajoutées; c) les distances d'isolement relatives aux conditions de champs homogènes ont été supprimées. Il a le statut de publication groupée de sécurité conformément au Guide 104 de l'IEC.

Varnost transformatorjev, dušilk, napajalnikov in njihovih kombinacij - 2-10. del: Posebne zahteve in preskusi za ločilne transformatorje z visoko izolacijsko stopnjo in ločilne transformatorje z izhodnimi napetostmi nad 1000 V

Ta del standarda IEC 61558 obravnava varnost ločilnih transformatorjev z visoko izolacijsko stopnjo in ločilnih transformatorjev z izhodnimi napetostmi nad 1000 V. V tem dokumentu so zajeti tudi transformatorji z vgrajenimi elektronskimi vezji.
OPOMBA 1: Varnost vključuje električne, toplotne in mehanske vidike.
Če ni navedeno drugače, izraz »transformator« zajema ločilne transformatorje z visoko izolacijsko stopnjo in ločilne transformatorje z izhodnimi napetostmi nad 1000 V pri izmeničnem toku oziroma 1500 V pri enosmernem toku.
Ta dokument se uporablja za stacionarne ali prenosne, eno- ali večfazne, zračno hlajene (naravno ali umetno) neodvisne ali povezane suhe transformatorje. Navitja so lahko enkapsulirana ali neenkapsulirana.
Za linearne napajalnike se uporablja ta dokument. Za stikalne napajalnike se uporablja standard IEC 61558-2-16 v kombinaciji s tem dokumentom. Če sta zahtevi v nasprotju ena z drugo, prevlada natančnejša.
Nazivna napajalna napetost ne presega 1000 V pri izmeničnem toku, nazivna napajalna frekvenca in notranja obratovalna frekvenca pa ne presegata 500 Hz.
Nazivna izhodna moč ne presega:
– 25 kVA za enofazne transformatorje;
– 40 kVA za večfazne transformatorje.
Ta dokument se uporablja za transformatorje brez omejitev nazivne izhodne moči,
o čemer se dogovorita kupec in proizvajalec.
Kjer je to primerno, izhodna napetost brez obremenitve ali nazivna izhodna napetost:
– ne presega 1000 V pri izmeničnem toku oziroma 1500 V pri enosmernem toku za ločilne transformatorje z visoko izolacijsko stopnjo;
– presega 1000 V pri izmeničnem toku oziroma 1500 V pri enosmernem toku in ne presega 15.000 V pri izmeničnem toku oziroma 15.000 V pri enosmernem toku
za ločilne transformatorje z izhodnimi napetostmi nad 1000 V.
Ta dokument se ne uporablja za:
– transformatorje iz standarda IEC 60076-11;
– neonske transformatorje iz standarda IEC 61050; ter
– napajalnike in pretvornike za uporabo z izdelki ali v izdelkih v skladu s standardom IEC 61347-2-10.
Ta dokument se ne uporablja za zunanja vezja in njihove sestavne dele, ki so namenjeni za povezavo z vhodnimi in izhodnimi priključki transformatorjev.
OPOMBA 2: Transformatorji, obravnavani v tem dokumentu, se uporabljajo samo, kadar v skladu s pravili namestitve ali standardom končnega izdelka ni potrebna dvojna ali okrepljena izolacija med vezji.
OPOMBA 3: Običajno so transformatorji namenjeni uporabi z opremo za zagotovitev napetosti, ki se razlikuje od napajalne napetosti zaradi funkcionalnih razlogov. Zaščito pred električnim udarom je mogoče zagotoviti (ali dopolniti) z drugimi elementi opreme, npr. z osrednjim delom. Dele izhodnih vezij je mogoče povezati z vhodnimi vezji ali zaščitno ozemljitvijo.
Ta dokument se uporablja za transformatorje, povezane z določeno opremo, v obsegu, kot ga določijo ustrezni tehnični odbori IEC.
Po potrebi se upošteva naslednje:
– dodatne zahteve za transformatorje, namenjene uporabi v vozilih, na krovih ladij in v zračnih plovilih (iz drugih ustreznih standardov, nacionalnih predpisov itd.);
– ukrepi za zaščito ohišja in komponent v ohišju proti zunanjim vplivom, kot so glive, mrčes, termiti, sončno sevanje in zaledenitev;
– različni pogoji glede prevoza, hrambe in delovanja transformatorjev;
– dodatne zahteve v skladu z drugimi ustreznimi standardi in nacionalnimi predpisi za transformatorje, namenjene uporabi v posebnih okoljih.
Za prihodnji tehnološki razvoj transformatorjev bo morda treba zvišati zgornjo mejo frekvenc, dotlej pa je mogoče ta dokument uporabljati kot navodilo.

General Information

• Status: Published
• Publication Date: 25-Jul-2024
• ICS: 29.180 - Transformers. Reactors
• 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: 6060 - Document made available - Publishing
• Start Date: 26-Jul-2024
• Due Date: 28-Feb-2023
• Completion Date: 26-Jul-2024
• Ref Project: SIST EN IEC 61558-2-10:2024 - Safety of transformers, reactors, power supply units and combinations thereof - Part 2-10: Particular requirements and tests for separating transformers with high insulation level and separating transformers with output voltages exceeding 1 000 V

Relations

• Replaces: EN 61558-2-10:2014 - Safety of transformers, reactors, power supply units and combinations thereof - Part 2-10: Particular requirements and tests for separating transformers with high insulation level and separating transformers with output voltages exceeding 1 000 V
• Effective Date: 23-Jan-2023

Overview

EN IEC 61558-2-10:2024 - Safety of transformers, reactors, power supply units and combinations thereof - Part 2-10 - specifies particular requirements and tests for separating transformers with high insulation level and for separating transformers with output voltages exceeding 1 000 V. Published as an EN adoption of IEC 61558-2-10:2024 (also available as the Redline RLV version), this second edition replaces the 2014 edition and is a technical revision aligned with IEC 61558-1:2017. The standard also covers transformers that incorporate electronic circuits and has the status of a group safety publication (IEC Guide 104).

Key topics and requirements

This part supplements IEC 61558-1 and focuses on safety, testing and construction criteria specific to high-insulation and high-output-voltage separating transformers. Major technical topics include:

• Insulation and dielectric testing - requirements for dielectric strength, insulation resistance and leakage current verification relevant to working voltages above 1 000 V.
• Clearances and creepage distances - updated rules for minimum separations and creepage for basic/supplementary insulation; note that clearances for homogeneous field conditions were removed in this edition.
• Overvoltage categories - inclusion of overvoltage categories I, II, III and IV for clearance and dielectric strength assessments.
• Mechanical and thermal requirements - tests for heating, mechanical strength, and resistance to environmental factors (moisture, dust, corrosion).
• Protection and marking - rules for protection against electric shock, short-circuit/overload protection, terminal and earthing provisions, and mandatory marking/technical information.
• Components and internal wiring - requirements for components, wiring, and connectors, including transformers incorporating electronic circuits.

(Topics reflect the standard’s clauses and test sections; refer to the full text for exact test voltages, dimensional minima and procedural details.)

Applications and who should use this standard

EN IEC 61558-2-10:2024 is essential for stakeholders involved in design, manufacture, testing and certification of high-isolation and high-voltage isolating transformers, including:

• Transformer and power supply manufacturers
• Electrical safety and compliance engineers
• Third‑party test laboratories and certification bodies
• OEMs specifying isolation transformers for industrial, medical, railway and power-distribution equipment
• Product safety assessors and procurement/specification teams

Use this standard to ensure product safety, compliance with European/CENELEC requirements, and to support conformity assessment and market access.

Related standards

Key related documents to consult alongside EN IEC 61558-2-10:2024:

• IEC 61558-1:2017 / EN IEC 61558-1 - General requirements and tests (normative companion).
• IEC 60076-11:2018 (transformer testing guidance referenced in the annex).
• IEC 62477-1:2022 (safety requirements for power electronic converters) and other standards listed in the normative bibliography.

For implementation, refer to the full EN IEC 61558-2-10:2024 text (and its Redline version) to obtain precise test methods, numerical limits and national adoption notes.

Standards Content (Sample)

SLOVENSKI STANDARD
01-oktober-2024
Varnost transformatorjev, dušilk, napajalnikov in njihovih kombinacij - 2-10. del:
Posebne zahteve in preskusi za ločilne transformatorje z visoko izolacijsko
stopnjo in ločilne transformatorje z izhodnimi napetostmi nad 1000 V
Safety of transformers, reactors, power supply units and combinations thereof - Part 2-
10: Particular requirements and tests for separating transformers with high insulation
level and separating transformers with output voltages exceeding 1 000 V
Sicherheit von Transformatoren, Netzgeräten, Drosseln und dergleichen - Teil 2-10:
Besondere Anforderungen und Prüfungen an Netztransformatoren mit hohem
Isolationspegel und Netztransformatoren mit Ausgangsspannungen über 1 000 V
Sécurité des transformateurs, bobines d'inductance, blocs d'alimentation et des
combinaisons de ces éléments - Partie 2-10: Règles particulières et essais pour les
transformateurs d'isolement à enroulements séparés à niveau d'isolement élevé et pour
les transformateurs d'isolement à enroulements séparés à tensions secondaires
supérieures à 1 000 V
Ta slovenski standard je istoveten z: EN IEC 61558-2-10:2024
ICS:
29.180 Transformatorji. Dušilke Transformers. Reactors
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN IEC 61558-2-10

NORME EUROPÉENNE
EUROPÄISCHE NORM July 2024
ICS 29.180 Supersedes EN 61558-2-10:2014
English Version
Safety of transformers, reactors, power supply units and
combinations thereof - Part 2-10: Particular requirements and
tests for separating transformers with high insulation level and
separating transformers with output voltages exceeding 1 000 V
(IEC 61558-2-10:2024)
Sécurité des transformateurs, bobines d'inductance, blocs Sicherheit von Transformatoren, Drosseln, Netzgeräten und
d'alimentation et des combinaisons de ces éléments - entsprechenden Kombinationen - Teil 2-10: Besondere
Partie 2-10 : Exigences particulières et essais pour les Anforderungen und Prüfungen für Netztransformatoren mit
transformateurs d'isolement à enroulements séparés à hohem Isolationspegel und Netztransformatoren mit
niveau d'isolement élevé et pour les transformateurs Ausgangsspannungen über 1 000 V
d'isolement à enroulements séparés à tensions secondaires (IEC 61558-2-10:2024)
supérieures à 1 000 V
(IEC 61558-2-10:2024)
This European Standard was approved by CENELEC on 2024-07-12. 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 CEN-CENELEC
Management Centre 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 CEN-CENELEC Management Centre has the
same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,
Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the
Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Türkiye and the United Kingdom.

European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2024 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN IEC 61558-2-10:2024 E

European foreword
The text of document 96/589/FDIS, future edition 2 of IEC 61558-2-10, prepared by IEC/TC 96
"Transformers, reactors, power supply units, and combinations thereof" was submitted to the IEC-
CENELEC parallel vote and approved by CENELEC as EN IEC 61558-2-10:2024.
The following dates are fixed:
• latest date by which the document has to be implemented at national (dop) 2025-04-12
level by publication of an identical national standard or by endorsement
• latest date by which the national standards conflicting with the (dow) 2027-07-12
document have to be withdrawn
This document supersedes EN 61558-2-10:2014 and all of its amendments and corrigenda (if any).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.
Any feedback and questions on this document should be directed to the users’ national committee. A
complete listing of these bodies can be found on the CENELEC website.
Endorsement notice
The text of the International Standard IEC 61558-2-10:2024 was approved by CENELEC as a
European Standard without any modification.
The endorsement notice of EN IEC 61558-1:2019 applies, except as follows.
Addition:
In the official version, for Bibliography, the following notes have to be added for the standard indicated:
IEC 60076-11:2018 NOTE Approved as EN IEC 60076-11:2018 (not modified)
IEC 60204-1:2016 NOTE Approved as EN 60204-1:2018
IEC 61050:1991 NOTE Approved as EN 61050:1992
IEC 61050:1991/A1:1994 NOTE Approved as EN 61050:1992/A1:1995
IEC 61347-2-10:2000 NOTE Approved as EN 61347-2-10:2001 (not modified)
IEC 61347-2-
NOTE Approved as EN 61347-2-10:2001/A1:2009 (not modified)
10:2000/A1:2008
IEC 61558 series NOTE Approved as EN 61558 series
IEC 61558-2-16:2021 NOTE Approved as EN IEC 61558-2-16:— (not modified)
IEC 62477-1:2022 NOTE Approved as EN IEC 62477-1:2023 (not modified)

to be published, Stage at the time of publication: FprEN IEC 61558-2-16:2021.
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments)
applies.
NOTE 1  Where an International Publication has been modified by common modifications, indicated by (mod),
the relevant EN/HD applies.
NOTE 2  Up-to-date information on the latest versions of the European Standards listed in this annex is available
here: www.cencenelec.eu.
Annex ZA of EN IEC 61558-1:2019 applies, except as follows.
Addition:
Publication Year Title EN/HD Year
IEC 61558-1 2017 Safety of transformers, reactors, power EN IEC 61558-1 2019
supply units and combinations thereof -
Part 1: General requirements and tests

IEC 61558-2-10 ®
Edition 2.0 2024-06
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
GROUP ENERGY EFFICIENCY PUBLICATION

PUBLICATION GROUPÉE SUR L'EFFICACITÉ ÉNERGÉTIQUE

Safety of transformers, reactors, power supply units and combinations thereof –

Part 2-10: Particular requirements and tests for separating transformers with

high insulation level and separating transformers with output voltages

exceeding 1 000 V
Sécurité des transformateurs, bobines d'inductance, blocs d'alimentation et des

combinaisons de ces éléments –

Partie 2-10 : Exigences particulières et essais pour les transformateurs

d'isolement à enroulements séparés à niveau d'isolement élevé et pour les

transformateurs d'isolement à enroulements séparés à tensions secondaires

supérieures à 1 000 V
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.180  ISBN 978-2-8322-8863-4

– 2 – IEC 61558-2-10:2024  IEC 2024
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 . 9
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 . 11
13 Short-circuit voltage . 12
14 Heating . 12
15 Short-circuit and overload protection . 12
16 Mechanical strength . 12
17 Protection against harmful ingress of dust, solid objects and moisture . 12
18 Insulation resistance, dielectric strength and leakage current . 12
19 Construction . 13
20 Components . 14
21 Internal wiring . 14
22 Supply connection and other external flexible cables or cords . 14
23 Terminals for external conductors . 14
24 Provisions for protective earthing. 14
25 Screws and connections . 15
26 Creepage distances, clearances and distances through insulation . 15
27 Resistance to heat, fire and tracking . 16
28 Resistance to rusting . 16
Annexes . 17
Bibliography . 18

Table 101 – Symbols indicating the kind of transformer . 10
Table 102 – Output voltage difference . 12
Table 103 – Table of dielectric strength test voltages for working voltages above
1 000 V . 13
Table 104 – Minimum clearances in air up to 2 000 m above sea level. 15
Table 105 – Minimum creepage distances for basic or supplementary insulation. 16

IEC 61558-2-10:2024  IEC 2024 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
SAFETY OF TRANSFORMERS, REACTORS,
POWER SUPPLY UNITS AND COMBINATIONS THEREOF –

Part 2-10: Particular requirements and tests for separating
transformers with high insulation level and separating
transformers with output voltages exceeding 1 000 V

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) IEC draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). IEC takes no position concerning the evidence, validity or applicability of any claimed patent rights in
respect thereof. As of the date of publication of this document, IEC had not received notice of (a) patent(s), which
may be required to implement this document. However, implementers are cautioned that this may not represent
the latest information, which may be obtained from the patent database available at https://patents.iec.ch. IEC
shall not be held responsible for identifying any or all such patent rights.
IEC 61558-2-10 has been prepared by IEC technical committee 96: Transformers, reactors,
power supply units and combinations thereof. It is an International Standard.
This second edition cancels and replaces the first edition published in 2014. 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) overvoltage categories I, II, III and IV for clearances and dielectric strength tests are
included;
– 4 – IEC 61558-2-10:2024  IEC 2024
c) clearances for homogenous field conditions deleted.
The text of this International Standard is based on the following documents:
Draft Report on voting
96/589/FDIS 96/595/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/standardsdev/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
separating transformers with high insulation level and separating transformers with output
voltages exceeding 1 000 V.
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 adapted 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 the data related to the
specific document. At this date, the document will be
• reconfirmed,
• withdrawn, or
• revised.
IEC 61558-2-10:2024  IEC 2024 – 5 –
INTRODUCTION
IEC TC 96 has a group safety function in accordance with IEC Guide 104 for transformers other
than those intended to supply distribution networks, in particular transformers and power
supply units intended to allow the application of protective measures against electric shock as
defined by TC 64, which is about electrical installations and protection against electric shock,
but in certain cases including the limitation of voltage and horizontal safety function for SELV,
in accordance with IEC 60364-4-41.
The group safety function (GSF) is used because of responsibility for safety extra-low voltage
(SELV) in accordance with IEC 61140:2016, 5.2.6 and IEC 60364-4-41:2005, 414.3.1 or control
circuits in accordance with IEC 60204-1:2016, 7.2.4.
The group safety function is used for each part of IEC 61558-2 because different standards of
the IEC 61558 series can be combined in one construction but in certain cases with no limitation
of rated output power.
For example an auto-transformer in accordance with IEC 61558-2-13 can be designed with a
separate SELV-circuit in accordance with the particular requirements for IEC 61558-2-6
relating to the general requirements of IEC 61558-1.

– 6 – IEC 61558-2-10:2024  IEC 2024
SAFETY OF TRANSFORMERS, REACTORS,
POWER SUPPLY UNITS AND COMBINATIONS THEREOF –

Part 2-10: Particular requirements and tests for separating
transformers with high insulation level and separating
transformers with output voltages exceeding 1 000 V

1 Scope
Replaceme
...