EN IEC 60947-6-1:2026

Low-voltage switchgear and controlgear - Part 6-1: Multiple function equipment - Transfer switching equipment

IEC 60947-6-1:2026 is available as IEC 60947-6-1:2026 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition. IEC 60947-6-1:2026 applies to transfer switching equipment (TSE), to be used in power systems for ensuring the continuity of the supply and allowing the energy management of the installation, by transferring a load between power supply sources, the rated voltage of which does not exceed 1 000 V AC or 1 500 V DC. Specific requirements for bypass/isolation transfer switch equipment are given in Annex C, ATSE having closed transition capability are given in Annex D, stand-alone ATS controllers are given in Annex E, and TSE for electric driven fire pump controllers are given in Annex F. It covers: - manually operated transfer switching equipment (MTSE); - remotely operated transfer switching equipment (RTSE); - automatic transfer switching equipment (ATSE), including the controller; - stand-alone ATS controllers; - bypass/isolation transfer switch equipment (BTSE); - ATSE having closed transition capability; - fire pump TSE. It does not cover: - TSE configurations that are not fully manufacturer type tested or marked according to this document as a complete transfer switch; - auxiliary contacts (for guidance, see IEC 60947-5-1); - transfer switches used in explosive atmospheres (for guidance, see IEC 60079 (all parts)); - embedded software design (for guidance, see IEC TR 63201); - cybersecurity aspects (for guidance, see IEC 63208); - TSE rated for direct-on-line starting asynchronous motor of design NE and HE, according to IEC 60034-12. (for guidance, see AC-3e utilisation category according to IEC 60947 4 1); - other types of TSE under consideration including overlapping neutral TSE, multi-source TSE (i.e. TSE with more than two sources of supply), TSE with load-shedding functions, bus-tie TSE, and hybrid TSE; - static transfer switches covered by IEC 62310 series. This fourth edition cancels and replaces the third edition published in 2021. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: - clarification of scope; - clarification of terms and definitions; - Annex C for Bypass/Isolation Transfer Switch Equipment; - Annex D for ATSE having closed transition capability; - Annex E for Stand-alone ATS controller; - Annex F for TSE used with electric driven fire pump control equipment.

Niederspannungsschaltgeräte - Teil 6-1: Mehrfunktionsschaltgeräte - Netzumschalter

Appareillage à basse tension - Partie 6-1: Matériels à fonctions multiples - Équipement de transfert de source

IEC 60947-6-1:2026 est disponible sous forme de IEC 60947-6-1:2026 RLV qui contient la Norme internationale et sa version Redline, illustrant les modifications du contenu technique depuis l'édition précédente.L'IEC 60947-6-1:2026 s'applique aux équipements de transfert de source (TSE) destinés à être utilisés au sein de réseaux d'énergie qui assurent la continuité de l'alimentation et permettent la gestion de l'énergie de l'installation, en transférant une charge entre des sources d'alimentation dont la tension assignée ne dépasse pas 1 000 V en courant alternatif ou 1 500 V en courant continu. Les exigences spécifiques aux équipements de transfert de source à shuntage/sectionnement sont fournies à l'Annexe C. Les exigences spécifiques aux ATSE sans coupure sont fournies à l'Annexe D. Les exigences spécifiques aux contrôleurs ATS autonomes sont fournies à l'Annexe E. Les exigences spécifiques aux TSE pour appareils de commande de pompe à incendie à entraînement électrique sont fournies à l'Annexe F. Le présent document couvre: - les équipements de transfert de source manœuvrés manuellement (MTSE); - les équipements de transfert de source manœuvrés à distance (RTSE); - les équipements de transfert de source automatiques (ATSE), y compris le contrôleur; - les contrôleurs ATS autonomes; - les équipements de transfert de source à shuntage/sectionnement (BTSE); - les ATSE sans coupure; - les TSE pour pompe à incendie. Le présent document ne couvre pas: - les configurations de TSE qui ne sont pas complètement soumises aux essais de type ou marquées par le fabricant conformément au présent document pour le transfert de source complet; - les contacts auxiliaires (voir les recommandations de l'IEC 60947 5-1); - les transferts de source utilisés en atmosphères explosives (voir les recommandations de l'IEC 60079 (toutes les parties)); - la conception des logiciels embarqués (voir les recommandations de l'IEC TR 63201); - les aspects liés à la cybersécurité (voir les recommandations de l'IEC 63208); - les TSE conçus pour les moteurs asynchrones à démarrage direct de types NE et HE selon l'IEC 60034-12 (voir les recommandations pour la catégorie d'emploi AC-3e selon l'IEC 60947 4 1); - les autres types de TSE à l'étude, notamment les TSE à transition avec recouvrement du neutre, les TSE multisources (c'est-à-dire les TSE comportant plus de deux sources d'alimentation), les TSE comportant des fonctions de délestage, les TSE comportant un jeu de barres de couplage et les TSE hybrides; - les commutateurs de transfert statique couverts par la série IEC 62310. Cette quatrième édition annule et remplace la troisième édition parue en 2021. Cette édition constitue une révision technique. Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente: - clarification du domaine d'application; - clarification des termes et définitions; - Annexe C, pour les équipements de transfert de source à shuntage/sectionnement; - Annexe D, pour les ATSE sans coupure; - Annexe E, pour les contrôleurs ATS autonomes; - Annexe F, pour les TSE utilisés avec un appareil de commande de pompe à incendie à entraînement électrique.

Nizkonapetostna stikalna in krmilna oprema - Del 6-1: Večfunkcijska oprema - Preklopna oprema (IEC 60947-6-1:2026)

IEC 60947-6-1:2026 se nanaša na opremo za preklop prenosa (TSE), ki se uporablja v elektroenergetskih sistemih za zagotavljanje neprekinjenosti oskrbe in omogočanje upravljanja z energijo v inštalacijah, s prenosom bremena med viri napajanja, katerih nazivna napetost ne presega 1 000 V AC ali 1 500 V DC. Posebne zahteve za opremo za preklop prenosa z obvodom/izolacijo so navedene v Prilogi C, ATSE z zmožnostjo zaprtega prehoda so navedene v Prilogi D, samostojni ATS krmilniki so navedeni v Prilogi E, in TSE za električno gnane krmilnike požarnih črpalk so navedeni v Prilogi F.
Pokritje:
- ročno upravljana oprema za preklop prenosa (MTSE);
- daljinsko upravljana oprema za preklop prenosa (RTSE);
- avtomatska oprema za preklop prenosa (ATSE), vključno s krmilnikom;
- samostojni ATS krmilniki;
- oprema za preklop prenosa z obvodom/izolacijo (BTSE);
- ATSE z zmožnostjo zaprtega prehoda;
- TSE za požarne črpalke.
Ne pokriva:
- TSE konfiguracij, ki niso v celoti tipsko preizkušene ali označene v skladu s tem dokumentom kot popolni preklopni stikalni sistemi;
- pomožnih kontaktov (za smernice glej IEC 60947-5-1);
- preklopnih stikal, ki se uporabljajo v eksplozivnih atmosferah (za smernice glej IEC 60079 (vsi deli));
- zasnove vgrajene programske opreme (za smernice glej IEC TR 63201);
- vidikov kibernetske varnosti (za smernice glej IEC 63208);
- TSE, ocenjene za neposredni zagon asinhronskega motorja zasnove NE in HE, v skladu z IEC 60034-12. (za smernice glej kategorijo uporabe AC-3e v skladu z IEC 60947 4 1);
- drugih vrst TSE, ki so v obravnavi, vključno s TSE z prekrivanjem nevtralnega vodnika, večvirovne TSE (tj. TSE z več kot dvema viroma napajanja), TSE s funkcijami zmanjševanja obremenitve, TSE za povezovanje zbiralnic in hibridne TSE;
- statičnih preklopnih stikal, ki jih pokriva serija IEC 62310.
Ta četrta izdaja preklicuje in nadomešča tretjo izdajo, objavljeno leta 2021. Ta izdaja predstavlja tehnično revizijo.
Ta izdaja vključuje naslednje pomembne tehnične spremembe v primerjavi s prejšnjo izdajo:
- pojasnitev področja uporabe;
- pojasnitev izrazov in definicij;
- Priloga C za opremo za preklop prenosa z obvodom/izolacijo;
- Priloga D za ATSE z zmožnostjo zaprtega prehoda;
- Priloga E za samostojni ATS krmilnik;
- Priloga F za TSE, uporabljene z opremo za krmiljenje električno gnanih požarnih črpalk.

General Information

• Status: Published
• Publication Date: 21-May-2026
• ICS: 29.120.40 - Switches
• ICS: 29.130.20 - Low voltage switchgear and controlgear
• Technical Committee: CLC/TC 121A - Low-voltage switchgear and controlgear
• Current Stage: 6060 - Document made available - Publishing
• Start Date: 22-May-2026
• Due Date: 29-Jan-2027
• Completion Date: 22-May-2026
• Directive: Harmonized Standard2014/30/EU - Directive 2014/30/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 electromagnetic compatibility (recast)
• Directive:

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  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 limits
• Mandate: M/511 - Mandate to CEN, CENELEC and ETSI relating to harmonised standards in the field of the Low Voltage Directive
• Mandate: M/552 - [C(2016) 7641 final] Standardisation request as regards harmonised standards in support of Directive 2014/30/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 electromagnetic compatibility
• Ref Project: SIST EN IEC 60947-6-1:2026 - Low-voltage switchgear and controlgear - Part 6-1: Multiple function equipment - Transfer switching equipment (IEC 60947-6-1:2026)

Relations

• Replaces: EN IEC 60947-6-1:2023 - Low-voltage switchgear and controlgear - Part 6-1: Multiple function equipment - Transfer switching equipment
• Effective Date: 20-Feb-2024
• Refers: EN 60068-2-2:2007 - Environmental testing - Part 2-2: Tests - Test B: Dry heat
• Effective Date: 28-Apr-2026
• Refers: EN IEC 60947-5-1:2025 - Low-voltage switchgear and controlgear - Part 5-1: Control circuit devices and switching elements - Electromechanical control circuit devices
• Effective Date: 28-Apr-2026
• Refers: EN IEC 63208:2025 - Low-voltage switchgear and controlgear and their assemblies - Security requirements
• Effective Date: 28-Apr-2026
• Refers: EN IEC 60812:2018 - Failure modes and effects analysis (FMEA and FMECA)
• Effective Date: 28-Apr-2026
• Refers: EN IEC 61439-1:2021 - Low-voltage switchgear and controlgear assemblies - Part 1: General rules
• Effective Date: 28-Apr-2026
• Refers: EN IEC 60947-2:2025 - Low-voltage switchgear and controlgear - Part 2: Circuit-breakers
• Effective Date: 28-Apr-2026
• Refers: EN IEC 55011:2025 - Industrial, scientific and medical equipment - Radio-frequency disturbance characteristics - Limits and methods of measurement
• Effective Date: 28-Apr-2026
• Refers: EN IEC 61557-12:2022 - Electrical safety in low voltage distribution systems up to 1 000 V AC and 1 500 V DC - Equipment for testing, measuring or monitoring of protective measures - Part 12: Power metering and monitoring devices (PMD)
• Effective Date: 28-Apr-2026
• Refers: EN 61000-4-13:2002/A2:2016 - Electromagnetic compatibility (EMC) - Part 4-13: Testing and measurement techniques - Harmonics and interharmonics including mains signalling at a.c. power port, low frequency immunity tests
• Effective Date: 28-Apr-2026
• Refers: EN 61000-4-13:2002 - Electromagnetic compatibility (EMC) - Part 4-13: Testing and measurement techniques - Harmonics and interharmonics including mains signalling at a.c. power port, low frequency immunity tests
• Effective Date: 28-Apr-2026
• Refers: EN IEC 60947-1:2021 - Low-voltage switchgear and controlgear - Part 1: General rules
• Effective Date: 28-Apr-2026
• Refers: HD 243 S12:1995 - Graphical symbols for use on equipment - Index, survey and compilation of the single sheets
• Effective Date: 28-Apr-2026
• Refers: EN IEC 60947-4-1:2025 - Low-voltage switchgear and controlgear - Part 4-1: Contactors and motor-starters - Electromechanical contactors and motor-starters
• Effective Date: 28-Apr-2026
• Refers: EN IEC 61557-12:2022/A1:2022 - Electrical safety in low voltage distribution systems up to 1 000 V AC and 1 500 V DC - Equipment for testing, measuring or monitoring of protective measures - Part 12: Power metering and monitoring devices (PMD)
• Effective Date: 28-Apr-2026

Overview

EN IEC 60947-6-1:2026 specifies requirements for low-voltage switchgear and controlgear, focusing on multiple function equipment known as transfer switching equipment (TSE). This international standard, developed by the International Electrotechnical Commission (IEC) and adopted by CLC, addresses TSE used to ensure power continuity and effective energy management by transferring electrical loads between two or more supply sources. Applicable to power systems with rated voltages not exceeding 1,000 V AC or 1,500 V DC, the standard is essential for installations where uninterrupted power supply is mission-critical.

The fourth edition of IEC 60947-6-1 brings significant technical revisions, including updates to scope, definitions, testing, and the addition of special requirements for specific applications such as fire pump controllers and equipment with closed transition capability.

Key Topics

• Scope and Applicability: EN IEC 60947-6-1:2026 applies to TSE used for reliable load transfer among alternate power sources, thus promoting operational continuity in low-voltage electrical installations.
• Types of Equipment Covered:
  • Manually Operated TSE (MTSE)
  • Remotely Operated TSE (RTSE)
  • Automatic Transfer Switching Equipment (ATSE)
  • Stand-alone ATS Controllers
  • Bypass/Isolation TSE (BTSE)
  • ATSE with Closed Transition Capability
  • Fire Pump TSE
• Primary Exclusions:
  • TSE not fully type tested or marked as per the standard
  • Static transfer switches (see IEC 62310 series)
  • Transfer switches for explosive atmospheres, embedded software, or cybersecurity aspects (referenced to other IEC standards)
• Product and Performance Requirements:
  • Product information, marking, installation and maintenance instructions
  • Constructional and performance requirements, including EMC and dielectric strength
  • Specific constructional details for special-use cases (Annexes C–F)
• Testing:
  • Type tests and routine tests to verify operational, electrical, mechanical, and EMC performance
  • Additional testing for critical load current and short-circuit conditions

Applications

EN IEC 60947-6-1:2026 is critical in sectors where reliable power switching is necessary for safety, operational continuity, and compliance. Key applications include:

• Industrial Facilities: Ensuring process uptime by enabling seamless transfer to backup power during grid outages or maintenance.
• Commercial Buildings and Data Centers: Providing business continuity by automatically or remotely switching loads between main and standby power sources.
• Healthcare and Emergency Services: Guaranteeing uninterrupted power to critical medical equipment and systems.
• Infrastructure and Utilities: Supporting the reliability of essential services by allowing flexible, automated transfer between multiple energy supplies.
• Fire Protection Systems: Mandating specialized TSE for electric driven fire pump controllers to meet stringent safety standards.

These applications benefit from improved equipment reliability, enhanced safety, and compliance with both regulatory and operational requirements.

Related Standards

Understanding EN IEC 60947-6-1:2026 in context offers further value:

• IEC 60947-1: Low-voltage switchgear and controlgear - General rules. Provides foundational definitions and requirements applicable to all parts of the series.
• IEC 60947-5-1: For auxiliary contacts and control circuit devices.
• IEC 60079: Standards for explosive atmospheres.
• IEC 62310 Series: Static transfer switches (not covered by this part).
• IEC TR 63201 & IEC TS 63208: Guidance on embedded software and cybersecurity in switchgear applications.

Staying aligned with these related standards ensures a comprehensive and up-to-date approach to the design, installation, and operation of transfer switching equipment in low-voltage systems.

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This overview of EN IEC 60947-6-1:2026 highlights its relevance for ensuring safe, reliable, and efficient power source transfer in modern electrical installations. By adhering to its requirements, organizations can maintain compliance and enhance the resilience of their electrical infrastructure.

Standards Content (Sample)

SLOVENSKI STANDARD
01-julij-2026
Nadomešča:
SIST EN IEC 60947-6-1:2023
Nizkonapetostne stikalne in krmilne naprave - 6-1. del: Večfunkcijska oprema -
Preklopna stikalna oprema (IEC 60947-6-1:2026)
Low-voltage switchgear and controlgear - Part 6-1: Multiple function equipment -
Transfer switching equipment (IEC 60947-6-1:2026)
Niederspannungsschaltgeräte - Teil 6-1: Mehrfunktionsschaltgeräte - Netzumschalter
(IEC 60947-6-1:2026)
Appareillage à basse tension - Partie 6-1: Matériels à fonctions multiples - Equipement
de transfert de source (IEC 60947-6-1:2026)
Ta slovenski standard je istoveten z: EN IEC 60947-6-1:2026
ICS:
29.120.40 Stikala Switches
29.130.20 Nizkonapetostne stikalne in Low voltage switchgear and
krmilne naprave controlgear
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN IEC 60947-6-1

NORME EUROPÉENNE
EUROPÄISCHE NORM May 2026
ICS 29.120.40; 29.130.20 Supersedes EN IEC 60947-6-1:2023
English Version
Low-voltage switchgear and controlgear - Part 6-1: Multiple
function equipment - Transfer switching equipment
(IEC 60947-6-1:2026)
Appareillage à basse tension - Partie 6-1: Matériels à Niederspannungsschaltgeräte - Teil 6-1:
fonctions multiples - Équipement de transfert de source Mehrfunktionsschaltgeräte - Netzumschalter
(IEC 60947-6-1:2026) (IEC 60947-6-1:2026)
This European Standard was approved by CENELEC on 2026-05-07. 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
© 2026 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN IEC 60947-6-1:2026 E

European foreword
The text of document 121A/711/FDIS, future edition 4 of IEC 60947-6-1, prepared by SC 121A "Low-
voltage switchgear and controlgear" of IEC/TC 121 "Switchgear and controlgear and their assemblies
for low voltage" was submitted to the IEC-CENELEC parallel vote and approved by CENELEC as
The following dates are fixed:
• latest date by which the document has to be implemented at national (dop) 2027-05-31
level by publication of an identical national standard or by endorsement
• latest date by which the national standards conflicting with the (dow) 2029-05-31
document have to be withdrawn
This document supersedes EN IEC 60947-6-1:2023 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.
This document is read in conjunction with EN IEC 60947-1:2021.
This document has been prepared under a standardization request addressed to CENELEC by the
European Commission. The Standing Committee of the EFTA States subsequently approves these
requests for its Member States.
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 60947-6-1:2026 was approved by CENELEC as a
European Standard without any modification.
In the official version, for Bibliography, the following notes have to be added for the standard indicated:
IEC 60034-12:2024 NOTE Approved as EN IEC 60034-12:2024 (not modified)
IEC 60079 (series) NOTE Approved as EN IEC 60079-7:2015/A1 (series)
IEC 60364-5-56:2018 NOTE Approved as HD 60364-5-56:2018 (not modified)
IEC 60947-3:2020 NOTE Approved as EN IEC 60947-3:2021 (not modified)
IEC 60947-6-2:2020 NOTE Approved as EN IEC 60947-6-2:2023 (not modified)
IEC 61010-2-201:2024 NOTE Approved as EN IEC 61010-2-201:2024 (not modified)
IEC 61439 (series) NOTE Approved as EN IEC 61439 (series)
IEC 62310 (series) NOTE Approved as EN 62310 (series)
IEC 62443 (series) NOTE Approved as EN IEC 62443-4-2:2019/AC:2022-09 (series)
IEC/TR 63201:2019 NOTE Approved as CLC IEC/TR 63201:2020 (not modified)
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.
Publication Year Title EN/HD Year
IEC 60068-2-2 2007 Environmental testing - Part 2-2: Tests - EN 60068-2-2 2007
Test B: Dry heat
IEC 60417 2025 Graphical symbols for use on equipment - - -
12-month subscription to regularly updated
online database comprising all graphical
symbols published in IEC 60417
IEC 60715 2017 Dimensions of low-voltage switchgear and EN 60715 2017
controlgear - Standardized mounting on
rails for mechanical support of switchgear,
controlgear and accessories
IEC 60812 2018 Failure modes and effects analysis (FMEA EN IEC 60812 2018
and FMECA)
IEC 60947-1 2020 Low-voltage switchgear and controlgear - EN IEC 60947-1 2021
Part 1: General rules
IEC 60947-2 2024 Low-voltage switchgear and controlgear - EN IEC 60947-2 2025
Part 2: Circuit-breakers
IEC 60947-4-1 2023 Low-voltage switchgear and controlgear - EN IEC 60947-4-1 2025
Part 4-1: Contactors and motor-starters -
Electromechanical contactors and motor-
starters
IEC 60947-5-1 2024 Low-voltage switchgear and controlgear - EN IEC 60947-5-1 2025
Part 5-1: Control circuit devices and
switching elements - Electromechanical
control circuit devices
IEC 61000-4-13 2002 Electromagnetic compatibility (EMC) - Part EN 61000-4-13 2002
4-13: Testing and measurement
techniques - Harmonics and
interharmonics including mains signalling
at a.c. power port, low frequency immunity
tests
+ A1 2009 + A1 2009
+ A2 2015 + A2 2016
IEC 61439-1 2020 Low-voltage switchgear and controlgear EN IEC 61439-1 2021
assemblies - Part 1: General rules
IEC 61439-2 2020 Low-voltage switchgear and controlgear EN IEC 61439-2 2021
assemblies - Part 2: Power switchgear and
controlgear assemblies
IEC 61557-12 2018 Electrical safety in low voltage distribution EN IEC 61557-12 2022
systems up to 1 000 V AC and 1 500 V DC
- Equipment for testing, measuring or
monitoring of protective measures - Part
12: Power metering and monitoring
devices (PMD)
+ A1 2021 + A1 2022
IEC 61812-1 2023 Time relays and coupling relays for EN IEC 61812-1 2024
industrial and residential use - Part 1:
Requirements and tests
IEC 63208 2025 Low-voltage switchgear and controlgear EN IEC 63208 2025
and their assemblies - Security
requirements
CISPR 11 2024 Industrial, scientific and medical equipment EN IEC 55011 2025
- Radio-frequency disturbance
characteristics - Limits and methods of
measurement
IEC 60947-6-1 ®
Edition 4.0 2026-04
INTERNATIONAL
STANDARD
Low-voltage switchgear and controlgear -
Part 6-1: Multiple function equipment - Transfer switching equipment
ICS 29.120.40; 29.130.20 ISBN 978-2-8327-1141-5

IEC 60947-6-1:2026-04(en)
IEC 60947-6-1:2026 © IEC 2026
CONTENTS
FOREWORD . 6
INTRODUCTION . 8
1 Scope . 9
2 Normative references . 10
3 Terms and definitions . 11
3.1 Alphabetical index of terms . 11
3.2 Transfer switching devices . 13
3.3 Operation of TSE . 15
3.4 Main contact positions . 17
3.5 Symbols and abbreviations used in this document . 18
4 Classification . 18
5 Characteristics . 19
5.1 Summary of characteristics . 19
5.2 Type and characteristics of equipment . 19
5.3 Rated and limiting values for the main circuit . 20
5.3.1 General . 20
5.3.2 Rated voltages . 20
5.3.3 Rated operational current (I ) . 20
e
5.3.4 Rated frequency . 20
5.3.5 Rated making and breaking capacities . 21
5.3.6 Short-circuit characteristics . 21
5.4 Utilization category . 22
5.5 Control circuits . 22
5.5.1 General . 22
5.5.2 Electromechanical devices operating the main circuit . 22
5.5.3 ATS controller . 23
5.6 Auxiliary circuits . 23
6 Product information . 23
6.1 Nature of information . 23
6.2 Marking . 23
6.3 Instructions for installation, operation and maintenance, decommissioning
and dismantling . 25
6.4 Environmental information . 26
7 Normal service, mounting and transport conditions . 27
8 Constructional and performance requirements . 27
8.1 Constructional requirements . 27
8.1.1 General . 27
8.1.2 Materials . 27
8.1.3 Indication . 28
8.1.4 Equipment suitable for isolation . 28
8.1.5 Opening and closing of main contacts . 28
8.1.6 Clearances and creepage distances . 29
8.1.7 Provision for protective earthing . 29
8.1.8 Stored charge energy circuit . 29
8.1.9 Stored energy closing . 29
IEC 60947-6-1:2026 © IEC 2026
8.1.10 Dedicated enclosures for TSE . 29
8.1.11 Communication . 29
8.2 Performance requirements . 30
8.2.1 Operating conditions . 30
8.2.2 Temperature-rise . 31
8.2.3 Dielectric properties . 31
8.2.4 Ability to make, carry, and break under no-load, normal load and
overload conditions . 31
8.2.5 Ability to make and break under short-circuit conditions . 34
8.2.6 Critical load current performance of TSE with DC rating . 35
8.3 Electromagnetic compatibility (EMC) . 35
8.3.1 General . 35
8.3.2 Immunity . 35
8.3.3 Emission . 36
9 Tests . 36
9.1 Kinds of tests . 36
9.2 Type tests . 36
9.2.1 General test conditions . 36
9.2.2 Test sequences . 37
9.2.3 Test sequence I – General performance characteristics . 39
9.2.4 Test sequence II – Operational performance capability . 46
9.2.5 Test sequence III – Short-circuit performance capability . 51
9.2.6 Test sequence IV – Conditional short-circuit current . 54
9.2.7 Test sequence V – Critical load current performance of equipment with
a DC rating . 55
9.2.8 Test sequence VI – EMC tests . 58
9.3 Routine tests . 60
9.4 Environmental tests . 62
Annex A (normative) Assignment of utilization categories based on results of tests . 64
Annex B (informative) Items subject to agreement between manufacturer and user . 65
Annex C (normative) Bypass/isolation transfer switch equipment . 66
C.1 General . 66
C.2 (void) . 66
C.3 (void) . 66
C.4 Classification . 66
C.5 Characteristics . 66
C.6 Product information . 66
C.7 Normal service, mounting and transport conditions . 66
C.8 Constructional and performance requirements . 67
C.8.1 General . 67
C.8.2 Construction requirements . 67
C.8.3 Performance requirements . 68
C.9 Tests . 70
C.9.1 General . 70
C.9.2 Interlocking function verification. 70
C.9.3 Full assembly tests . 70
C.9.4 Routine tests . 70
C.10 BTSE typical circuits and main components . 71
IEC 60947-6-1:2026 © IEC 2026
C.10.1 Example of operating sequence of a single line fixed type BTSE . 71
C.10.2 Example of operating sequence of a double line fixed type BTSE . 72
C.10.3 Example of operating sequence of a double line withdrawable type
BTSE . 73
C.10.4 Example of operating sequence of a double line load-break
withdrawable type BTSE . 74
C.10.5 Example of operating sequence of a single line withdrawable type BTSE . 75
Annex D (normative) ATSE having closed transition capability . 76
D.1 General . 76
D.2 (void) . 76
D.3 (void) . 76
D.4 Classification . 76
D.5 Characteristics . 76
D.6 Product information . 76
D.6.1 General . 76
D.6.2 Product instructions for operation . 77
D.7 Normal service, mounting and transport conditions . 77
D.8 Constructional and performance requirements . 77
D.8.1 General . 77
D.8.2 Operating mechanism . 78
D.8.3 Controls, sequence, and limits of operation . 78
D.8.4 Performance requirements . 79
D.9 Tests . 80
D.9.1 General . 80
D.9.2 Test procedure . 80
D.9.3 Figures to clarify closed transition transfer . 81
Annex E (normative) Stand-alone ATS controller . 85
E.1 General . 85
E.2 (void) . 85
E.3 (void) . 85
E.4 Classification . 85
E.5 Characteristics . 85
E.6 Product information . 85
E.6.1 General . 85
E.6.2 Product instructions for operation . 87
E.7 Normal service, mounting and transport conditions . 88
E.8 Constructional and performance requirements . 88
E.8.1 Constructional requirements . 88
E.8.2 Performance requirements . 90
E.8.3 Electromagnetic compatibility (EMC) . 90
E.9 Tests . 90
E.9.1 General . 90
E.9.2 List of type tests . 90
E.9.3 Wire flexing test . 91
E.9.4 EMC tests . 91
E.9.5 Stand-alone ATS controller routine test . 92
E.9.6 Environmental tests . 92
E.9.7 Example to clarify stand-alone ATS controller operating transfer time . 92

IEC 60947-6-1:2026 © IEC 2026
Annex F (normative) TSE used with electric driven fire pump control equipment . 93
F.1 General . 93
F.2 Normative references . 93
F.3 Terms and definitions. 93
F.4 Classification . 93
F.5 Characteristics . 93
F.6 Product information . 93
F.7 Normal service, mounting and transport conditions . 94
F.8 Constructional, functional, and performance requirements . 94
F.8.1 General . 94
F.8.2 General . 94
F.8.3 Manual operating means for maintenance and servicing . 94
F.8.4 ATSE Voltage sensing . 95
F.8.5 ATSE Initiation of transfer to secondary supply source . 95
F.8.6 ATSE Frequency monitoring of generator source . 95
F.8.7 Indicators of transfer . 95
F.8.8 Integral protective devices . 95
F.8.9 ATSE Generator starting contacts . 95
F.8.10 Power circuit components . 96
F.8.11 Operating mechanism . 96
F.9 Tests . 96
F.9.1 General . 96
F.9.2 Type tests. 96
Bibliography . 97

Figure 1 – Example of operating sequences for TSE with three positions . 26
Figure 2 – Test circuit for connection to source I and source II supplies . 61
Figure 3 – Test circuit for the verification of making and breaking capacities . 62
Figure C.1 – Single line fixed type BTSE . 71
Figure C.2 – Double line fixed type BTSE . 72
Figure C.3 – Double line withdrawable type BTSE . 73
Figure C.4 – Double line load-break withdrawable type BTSE . 74
Figure C.5 – Single line withdrawable type BTSE . 75
Figure D.1 – Additional control circuit and external disconnecting devices . 79
Figure D.2 – Open transition . 81
Figure D.3 – Closed transition. 81
Figure D.4 – Example to describe a typical open and closed transition operating
sequence . 82
Figure D.5 – Example of an operating sequence with a fail to open position II contacts
within 100 ms during a return transfer in closed transition . 83
Figure D.6 – Example of an operating sequence with a fail to open both position I and
position II contacts during a return transfer in closed transition and showing the
removal of the condition by signalling an external device to open (source II) . 84
Figure E.1 – Example to show the stand-alone ATS controller operating transfer time . 92

Table 1 – Utilization categories . 22
Table 2 – Product information . 23
IEC 60947-6-1:2026 © IEC 2026
Table 3 – Verification of making and breaking capacity – Conditions for making and
breaking corresponding to the utilization categories . 32
Table 4 – Verification of operational performance – Conditions for making and breaking
corresponding to the utilization categories . 33
Table 5 – Value of the test current for the verification of the ability to operate under
short-circuit conditions . 34
Table 6 – Value of the test current for the verification of the ability to operate under
short-circuit conditions (harmonized table) . 35
Table 7 – Acceptance criteria of immunity test . 36
Table 8 – List of type tests (overall scheme of test sequences) . 37
Table 9 – List of type tests to which a derived TSE shall be submitted . 38
Table 10 – Number and duration of operating cycles for the making and breaking
capacity test . 47
Table 11 – Number and rate of operating cycles for the electrical and mechanical
operational performance tests for type A utilization categories . 48
Table 12 – Number and rate of operating cycles for the electrical and mechanical
operational performance tests for type B utilization categories . 49
Table 13 – Temperature-rise limits for terminals and accessible parts. 50
Table 14 – Number of operating cycles corresponding to the critical load current . 57
Table 15 – Test circuit parameters for Table 14 . 57
Table 16 – Test sequence V: Critical load current performance of equipment with a DC
rating . 57
Table D.1 – Product information . 77
Table E.1 – Product information . 86
Table E.2 – List of type tests for the stand-alone ATS controller . 91
Table F.1 – Product information . 94

IEC 60947-6-1:2026 © IEC 2026
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
Low-voltage switchgear and controlgear -
Part 6-1: Multiple function equipment -
Transfer switching equipment
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 60947-6-1 has been prepared by sub-committee 121A: Low-voltage switchgear and
controlgear, of IEC technical committee 121: Switchgear and controlgear and their assemblies
for low voltage. It is an International Standard.
This fourth edition cancels and replaces the third edition published in 2021. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
– clarification of scope;
– clarification of terms and definitions;
– Annex C for Bypass/Isolation Transfer Switch Equipment;
– Annex D for ATSE having closed transition capability;
IEC 60947-6-1:2026 © IEC 2026
– Annex E for Stand-alone ATS controller;
– Annex F for TSE used with electric driven fire pump control equipment.
The text of this International Standard is based on the following documents:
Draft Report on voting
121A/711/FDIS 121A/719/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.
A list of all the parts in the IEC 60947 series, published under the general title Low-voltage
switchgear and controlgear, can be found on the IEC website.
This document is to be read in conjunction with IEC 60947-1:2020, Low voltage switchgear and
controlgear - Part 1: General rules.
The provisions of the general rules are applicable to IEC 60947-6-1 where specifically called
for. General rules clauses and subclauses thus applicable as well as tables, figures and
appendices are identified by reference to IEC 60947-1:2020, for example, 1.2.3, Table 4, or
Annex A of IEC 60947-1:2020.
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 60947-6-1:2026 © IEC 2026
INTRODUCTION
The availability of power in low voltage electrical installations is playing an ever increasing role
in modern society. In fact, this requirement is a fundamental characteristic for the creation of
economically and functionally efficient installations. A system able to switch a load from one
source to another safely and with minimum disturbance to the load reduces problems caused
by faulty conditions in the normal supply to the minimum.
All these operations, commonly known as "transfer switching", control the installations and can
be done automatically, remotely or manually.
Therefore, an installation with installed "transfer switching" capability:
– ensures the continuity of production processes;
– provides a backup source of power if the main network is out of service;
– reduces the effect caused by network faults on parts of the installation;
– achieves a good compromise between reliability, simplicity and cost-effectiveness;
– provides the facility manager and managing system with a power source able to supply all
or part of the installation.
Key factors motivating customers to use Transfer Switch Equipment (TSE) include:
– the continuous world growth population, the increasing number of electronic devices and
the new demands of electric vehicles;
– the mediated pressure on climate change with a resulting increase in the cost of energy;
– the evolution of the electricity market with a greater number of alternate energy sources;
– the user’s expectations of better grid reliability, better economic performance, and a desire
to manage their energy.
Stakeholders involved in the management of electricity also have new expectations:
– customers want to reduce the cost of their energy and to have a quality energy supply;
– suppliers want to reinforce confidence to their customers;
– producers expect to optimize their investments;
– governments and regulators are willing to create a competitive and sustainable energy
market.
Today, the performance of transfer switching equipment is defined by TSE manufacturers and
also by this document. Consultants, integrators, facility managers and end users rely on this
document for their power availability needs.
Transfer switching is often realised by implementing a transfer function within the electrical
installation, and this critical function needs to be appropriately designed. Using a TSE following
the requirements of this document ensure the safety and the performance of the transfer
function which are necessary for reaching the objectives listed above.

IEC 60947-6-1:2026 © IEC 2026
1 Scope
This document applies to transfer switching equipment (TSE), to be used in power systems for
ensuring the continuity of the supply and allowing the energy management of the installation,
by transferring a load between power supply sources, the rated voltage of which does not
exceed 1 000 V AC or 1 500 V DC.
Specific requirements for bypass/isolation transfer switch equipment are given in Annex C,
ATSE having closed transition capability are given in Annex D, stand-alone ATS controllers are
given in Annex E, and TSE for electric driven fire pump controllers are given in Annex F.
It covers:
– manually operated transfer switching equipment (MTSE);
– remotely operated transfer switching equipment (RTSE);
– automatic transfer switching equipment (ATSE), including the controller;
– stand-alone ATS controllers;
– bypass/isolation transfer switch equipment (BTSE);
– ATSE having closed transition capability;
– fire pump TSE.
It does not cover:
– TSE configurations that are not fully manufacturer type tested or marked according to this
document as a complete transfer switch;
– auxiliary contacts (for guidance, see IEC 60947-5-1);
– transfer switches used in explosive atmospheres (for guidance, see IEC 60079 (all parts));
– embedded software design (for guidance, see IEC TR 63201);
– cybersecur
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