SIST EN IEC 60947-9-2:2025

Low-voltage switchgear and controlgear - Part 9-2: Active arc-fault mitigation systems - Optical-based internal arc-detection and mitigation devices (IEC 60947-9-2:2021)

This document covers internal arc-fault control devices, hereinafter referred to as IACD, which
are intended to:
- detect internal arc-faults in low-voltage switchgear and controlgear assemblies, by
processing (at a minimum) the optical effect of an internal arc-fault, and
- operate mitigation device (either external or combined)
in order to minimize the effects of the internal arc-fault (see Figure 1).
For the purpose of this document the terms "light" or "optical" covers more than visible spectra.
They may cover also, for example, infrared or ultraviolet electromagnetic radiations (see
Annex D).
For combined-type IACD, this document is considered in addition to the relevant product
standard for internal arc-fault mitigation devices (IARD per IEC TS 63107:2020). Compliance
to the relevant product standard is mandatory and cannot be claimed by testing to this document
alone.
NOTE 1 Low-voltage switchgear and controlgear assemblies are usually described by IEC 61439 series.
[Figure 1]
Therefore, this document covers the following:
- internal arc-fault control device (stand-alone, multifunction or combined);
- one or more associated sensor(s) used to detect optical effect of the internal arc-fault;
- sensor(s), sensing another physical effect, to confirm the fault;
- associated or combined mitigation device.
An IACD is not intended to trigger under normal operation of low-voltage switchgear and
controlgear (i.e. absence of internal arc-fault), including normal arcing associated with
operation of disconnecting and switching devices.
This document only covers the following methods:
- optical detection of the light caused by an internal arc-fault;
- optional confirmation of internal arc-fault by line current measurement.
Many different conductive materials could be used in LV assemblies (e.g. steel, copper,
aluminium). Nevertheless, tests specified in this document are deemed to represent the most
critical and challenging conditions for arc-detection and cover all combinations of conductive
materials.
NOTE 2 Compared to other materials (e.g. steel, aluminium), copper leads to a lower optical radiation energy.
The rated voltage of the assembly in which an IACD is installed does not exceed 1 000 V AC.
Such devices are designed to be operated and maintained by skilled persons only.
This document does not cover:
- DC internal arc-fault detection and control;
- overcurrent relays;
- AFDD (arc-fault detection devices) as defined by IEC 62606;
- guidance on installation within assemblies;
NOTE 3 The integration of an IACD into an assembly is described in IEC TS 63107.
- use with additional measures needed for installation and operation within explosive
atmospheres. These are given in IEC 60079 series documents;
- requirements for embedded software and firmware design rules; for this subject, the
manufacturer is responsible for taking additional safety measures;
NOTE 4 IEC TR 63201 describes rules for firmware and embedded software development preventing errors in
software.
- cybersecurity aspects; for this subject, the manufacturer is responsible for taking additional
safety measures;
NOTE 5 See IEC TS 63208.
- mobile applications.
NOTE 6 Even when addressing internal arc-fault mitigation devices, this document does not supersede any other
relevant product standard (e.g. IEC 60947-2 or IEC 60947-9-1).
NOTE 7 DC arcing fault phenomena are under consideration. Further investigation is needed to comprehend DC
arcing phenomena and required sensing.

Niederspannungsschaltgeräte - Aktive Systeme zur Abschwächung von Störlichtbögen - Teil 9-2: Optische Geräte zur Erfassung und Abschwächung innerer Lichtbögen (IEC 60947-9-2:2021)

Appareillage à basse tension - Partie 9-2: Systèmes actifs de limitation des défauts d'arc - Dispositifs optiques de détection et de limitation d'arcs internes (IEC 60947-9-2:2021)

L'IEC 60947-9-2:2021 s’applique aux dispositifs de contrôle de défaut d’arc interne, ci-après désignés IACD, qui sont destinés à:
– détecter les défauts d’arc interne dans les ensembles d’appareillage à basse tension, en traitant (a minima) le phénomène optique d’un défaut d’arc interne, et
– faire fonctionner un dispositif de limitation (externe ou combiné) afin de réduire le plus possible les effets de défaut d’arc interne

Nizkonapetostne stikalne in krmilne naprave - 9-2. del: Aktivni sistemi za blažitev učinkov okvarnega obloka - Naprave za odkrivanje in ublažitev lokov, ki temeljijo na optičnem sistemu (IEC 60947-9-2:2021)

General Information

• Status: Published
• Publication Date: 17-Jul-2025
• ICS: 29.120.40 - Switches
• ICS: 29.130.20 - Low voltage switchgear and controlgear
• Technical Committee: SKA - Switchgear and control gear
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 15-Jul-2025
• Due Date: 19-Sep-2025
• Completion Date: 18-Jul-2025
• Directive: 2014/30/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: 2014/35/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: EN IEC 60947-9-2:2025 - Low-voltage switchgear and controlgear - Part 9-2: Active arc-fault mitigation systems - Optical-based internal arc-detection and mitigation devices

Standards Content (Sample)

SLOVENSKI STANDARD
01-september-2025
Nizkonapetostne stikalne in krmilne naprave - 9-2. del: Aktivni sistemi za blažitev
učinkov okvarnega obloka - Naprave za odkrivanje in ublažitev lokov, ki temeljijo
na optičnem sistemu (IEC 60947-9-2:2021)
Low-voltage switchgear and controlgear - Part 9-2: Active arc-fault mitigation systems -
Optical-based internal arc-detection and mitigation devices (IEC 60947-9-2:2021)
Niederspannungsschaltgeräte - Aktive Systeme zur Abschwächung von Störlichtbögen -
Teil 9-2: Optische Geräte zur Erfassung und Abschwächung innerer Lichtbögen (IEC
60947-9-2:2021)
Appareillage à basse tension - Partie 9-2: Systèmes actifs de limitation des défauts d'arc
- Dispositifs optiques de détection et de limitation d'arcs internes (IEC 60947-9-2:2021)
Ta slovenski standard je istoveten z: EN IEC 60947-9-2:2025
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 60947-9-2

NORME EUROPÉENNE
EUROPÄISCHE NORM July 2025
ICS 29.120.40; 29.130.20
English Version
Low-voltage switchgear and controlgear - Part 9-2: Active arc-
fault mitigation systems - Optical-based internal arc-detection
and mitigation devices
(IEC 60947-9-2:2021)
Appareillage à basse tension - Partie 9-2: Systèmes actifs Niederspannungsschaltgeräte - Aktive Systeme zur
de limitation des défauts d'arc - Dispositifs optiques de Abschwächung von Störlichtbögen - Teil 9-2: Optische
détection et de limitation d'arcs internes Geräte zur Erfassung und Abschwächung innerer
(IEC 60947-9-2:2021) Lichtbögen
(IEC 60947-9-2:2021)
This European Standard was approved by CENELEC on 2021-05-31. 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
© 2025 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN IEC 60947-9-2:2025 E

European foreword
The text of document 121A/406/FDIS, future edition 1 of IEC 60947-9-2, 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) 2026-07-31
level by publication of an identical national standard or by endorsement
• latest date by which the national standards conflicting with the (dow) 2028-07-31
document have to be withdrawn
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 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.
For the relationship with EU Legislation, see informative Annex ZZ, which is an integral part of this
document.
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 60947-9-2:2021 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 60079 (series) NOTE Approved as EN IEC 60079 (series)
IEC 60269 (series) NOTE Approved as EN 60269 (series)
IEC 60664-1:2020 NOTE Approved as EN IEC 60664-1:2020 (not modified)
IEC 60947-3 NOTE Approved as EN IEC 60947-3
IEC 61439 (series) NOTE Approved as EN IEC 61439 (series)
IEC 61439-1:2020 NOTE Approved as EN IEC 61439-1:2021 (not modified)
IEC 61439-2:2020 NOTE Approved as EN IEC 61439-2:2021 (not modified)
IEC 62474 NOTE Approved as EN IEC 62474
IEC 62606 NOTE Approved as EN 62606
IEC/TR 63201 NOTE Approved as CLC IEC/TR 63201
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 60068-2-6 2007 Environmental testing - Part 2-6: Tests - EN 60068-2-6 2008
Test Fc: Vibration (sinusoidal)
IEC 60068-2-27 2008 Environmental testing - Part 2-27: Tests - EN 60068-2-27 2009
Test Ea and guidance: Shock
IEC 60068-2-30 2005 Environmental testing - Part 2-30: Tests - EN 60068-2-30 2005
Test Db: Damp heat, cyclic (12 h + 12 h
cycle)
IEC 60255-27 2013 Measuring relays and protection EN 60255-27 2014
equipment - Part 27: Product safety
requirements
IEC 60695-2-10 - Fire hazard testing - Part 2-10: EN IEC 60695-2-10 2021
Glowing/hot-wire based test methods -
Glow-wire apparatus and common test
procedure
IEC 60695-2-11 2014 Fire hazard testing - Part 2-11: EN IEC 60695-2-11 2021
Glowing/hot-wire based test methods -
Glow-wire flammability test method for
end-products (GWEPT)
IEC 60695-2-12 - Fire hazard testing - Part 2-12: EN IEC 60695-2-12 2021
Glowing/hot-wire based test methods -
Glow-wire flammability index (GWFI) test
method for materials
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 60947-1 2020 Low-voltage switchgear and controlgear - EN IEC 60947-1 2021
Part 1: General rules
IEC 60947-2 2016 Low-voltage switchgear and controlgear - EN 60947-2 2017
Part 2: Circuit-breakers
+ A1 2019 + A1 2020
Publication Year Title EN/HD Year
IEC 60947-9-1 2019 Low-voltage switchgear and controlgear - EN IEC 60947-9-1 2019
Part 9-1: Active arc-fault mitigation
systems - Arc quenching devices
IEC 60990 2016 Methods of measurement of touch current EN 60990 2016
and protective conductor current
IEC 61482-1-2 2014 Live working - Protective clothing against EN 61482-1-2 2014
the thermal hazards of an electric arc -
Part 1-2: Test methods - Method 2:
Determination of arc protection class of
material and clothing by using a
constrained and directed arc (box test)
IEC 61557-2 - Electrical safety in low voltage distribution EN IEC 61557-2 2021
systems up to 1 000 V a.c. and 1 500 V
d.c. - Equipment for testing, measuring or
monitoring of protective measures - Part 2:
Insulation resistance
CISPR 11 (mod) 2015 Industrial, scientific and medical equipment EN 55011 2016
- Radio-frequency disturbance
characteristics - Limits and methods of
measurement
+ A1 2016 + A1 2017
+ A11 2020
CISPR 32 2015 Electromagnetic compatibility of EN 55032 2015
multimedia equipment - Emission
requirements
+ AC 2016
+ A11 2020
ISO 3864-1 2011 Graphical symbols - Safety colours and - -
safety signs – Part 1: Design principles for
safety signs and safety markings
ISO 3864-2 2016 Graphical symbols - Safety colours and - -
safety signs – Part 2: Design principles for
product safety labels
Annex ZZ
(informative)
Relationship between this European standard and the safety
objectives of Directive 2014/35/EU [2014 OJ L96] aimed to be
covered
This European standard has been prepared under a Commission’s standardisation request relating to
harmonised standards in the field of the Low Voltage Directive, M/511, to provide one voluntary means
of conforming to safety objectives of 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
[2014 OJ L96].
Once this standard is cited in the Official Journal of the European Union under that Directive,
compliance with the normative clauses of this standard given in Table ZZ.1 confers, within the limits of
the scope of this standard, a presumption of conformity with the corresponding safety objectives of
that Directive, and associated EFTA regulations.
Table ZZ.1 — Correspondence between this European standard and the Annex I of Directive
2014/35/EU [2014 OJ L96]
Safety objectives of Clause(s) / sub-clause(s) Remarks/note
Directive 2014/35/EU of this EN
1 a) 4, 6.1, 6.2, 6.3
4, 6.1, 6.3, 9.3.3, 9.3.4, A.5, B.5,
1 b)
E.2.7
see 2 a) to 2 d) and 3 a) to 3 c)
1 c) 4, 6, B.5
in this table
2 a) 4, 5, 6, 7, 8.1, 8.2, 9.2, 9.3, 9.4
2 b) 4, 6, 8.1, 8.2, 9.3
2 c) 4, 5, 8.1, 9
2 d) 4, 5, 8.1, 9.1, 9.3, 9.4
3 a) 4, 6.3, 7, 8.1, 9
3 b) 4, 6, 8.3, 9.1, 9.3, 9.4
3 c) 4, 5, 9.3
WARNING 1 — Presumption of conformity stays valid only as long as a reference to this European
standard is maintained in the list published in the Official Journal of the European Union. Users of this
standard should consult frequently the latest list published in the Official Journal of the European
Union.
WARNING 2 — Other Union legislation may be applicable to the product(s) falling within the scope of
this standard.
IEC 60947-9-2 ®
Edition 1.0 2021-04
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Low-voltage switchgear and controlgear –

Part 9-2: Active arc-fault mitigation systems – Optical-based internal

arc‑detection and mitigation devices

Appareillage à basse tension –

Partie 9-2: Systèmes actifs de limitation des défauts d'arc – Dispositifs optiques

de détection et de limitation d’arcs internes

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.120.40; 29.130.20 ISBN 978-2-8322-9606-6

– 2 – IEC 60947-9-2:2021 © IEC 2021
CONTENTS
FOREWORD . 7
INTRODUCTION . 9
1 Scope . 11
2 Normative references . 12
3 Terms and definitions . 13
4 Classification . 16
4.1 IACD type . 16
4.1.1 Stand-alone type IACD . 16
4.1.2 Multifunction-type IACD . 17
4.1.3 Combined-type IACD . 17
4.2 Combination of sensors . 18
4.2.1 Optical sensors-only type . 18
4.2.2 Optical sensors and secondary sensors type . 18
4.3 Binary output types . 19
4.3.1 Operate output . 19
4.3.2 Auxiliary binary output .
...