EN IEC 63445:2025

SLOVENSKI STANDARD
01-februar-2026
Stikalna naprava za povezovanje referenčnega vodnika sistema (IEC 63445:2025)
System referencing conductor switching device (IEC 63445:2025)
Schalteinrichtungen für den Sternpunktverbindungsleiter (IEC 63445:2025)
Appareil de connexion du conducteur de référence du système (IEC 63445:2025)
Ta slovenski standard je istoveten z: EN IEC 63445:2025
ICS:
29.130.01 Stikalne in krmilne naprave Switchgear and controlgear
na splošno in general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN IEC 63445

NORME EUROPÉENNE
EUROPÄISCHE NORM November 2025
ICS 27.015; 29.020
English Version
System referencing conductor switching device
(IEC 63445:2025)
Appareil de connexion du conducteur de référence du Schalteinrichtungen für den Sternpunktverbindungsleiter
système (IEC 63445:2025)
(IEC 63445:2025)
This European Standard was approved by CENELEC on 2025-10-13. 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 63445:2025 E
European foreword
The text of document 23K/123/FDIS, future edition 1 of IEC 63445, prepared by SC 23K "Electrical
Energy Efficiency products" of IEC/TC 23 "Electrical accessories" was submitted to the IEC-CENELEC
parallel vote and approved by CENELEC as EN IEC 63445:2025.
The following dates are fixed:
• latest date by which the document has to be implemented at national (dop) 2026-10-31
level by publication of an identical national standard or by endorsement
• latest date by which the national standards conflicting with the (dow) 2028-10-31
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.
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 63445:2025 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 60364-8-82 NOTE Approved as HD 60364-8-82
IEC 60364-8-82:2022 NOTE Approved as HD 60364-8-82:2025 (not modified) +A11:2025
IEC 60715 NOTE Approved as EN 60715
IEC 60364-4-41:2005 NOTE Approved as HD 60364-4-41:2017 +A11:2017
IEC 60664-3 NOTE Approved as EN 60664-3
IEC 60664-1:2020 NOTE Approved as EN IEC 60664-1:2020 (not modified)
IEC 60664-1 NOTE Approved as EN IEC 60664-1
IEC 61032 NOTE Approved as EN 61032
IEC 60947-1:2020 NOTE Approved as EN IEC 60947-1:2021 (not modified)
IEC 60947-3:2020 NOTE Approved as EN IEC 60947-3:2021 (not modified)
IEC 60695-2-10 NOTE Approved as EN IEC 60695-2-10
IEC 60695-2-11 NOTE Approved as EN IEC 60695-2-11
IEC 60068-2-30:2005 NOTE Approved as EN 60068-2-30:2005 (not modified)
IEC 60068-3-4:2023 NOTE Approved as EN IEC 60068-3-4:2023 (not modified)
IEC 61000-4-11 NOTE Approved as EN IEC 61000-4-11
IEC 61000-4-5 NOTE Approved as EN 61000-4-5
IEC 61000-4-4 NOTE Approved as EN 61000-4-4
IEC 61000-4-2 NOTE Approved as EN IEC 61000-4-2
IEC 61000-4-3 NOTE Approved as EN IEC 61000-4-3
IEC 61000-4-6 NOTE Approved as EN IEC 61000-4-6
IEC 61000-4-8 NOTE Approved as EN 61000-4-8
IEC 61000-6-1 NOTE Approved as EN IEC 61000-6-1
IEC 60112 NOTE Approved as EN IEC 60112
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 60364-8-82 - Low-voltage electrical installations - Part 8- HD 60364-8-82 -
82: Functional aspects - Prosumer's low-
voltage electrical installations
IEC 61000-4-2 2008 Electromagnetic compatibility (EMC) - Part EN 61000-4-2 2009
4-2: Testing and measurement techniques
- Electrostatic discharge immunity test
IEC 61000-4-3 - Electromagnetic compatibility (EMC) - Part EN IEC 61000-4-3 -
4-3 : Testing and measurement techniques
- Radiated, radio-frequency,
electromagnetic field immunity test
IEC 61000-4-4 - Electromagnetic compatibility (EMC) - Part EN 61000-4-4 -
4-4: Testing and measurement techniques
- Electrical fast transient/burst immunity
test
IEC 61000-4-5 - Electromagnetic compatibility (EMC) - Part EN 61000-4-5 -
4-5: Testing and measurement techniques
- Surge immunity test
IEC 61000-4-6 - Electromagnetic compatibility (EMC) - Part EN IEC 61000-4-6 -
4-6: Testing and measurement techniques
- Immunity to conducted disturbances,
induced by radio-frequency fields
IEC 61000-4-11 - Electromagnetic compatibility (EMC) - Part EN IEC 61000-4-11 -
4-11: Testing and measurement
techniques - Voltage dips, short
interruptions and voltage variations
immunity tests for equipment with input
current up to 16 A per phase
IEC 63445 ®
Edition 1.0 2025-09
INTERNATIONAL
STANDARD
System referencing conductor switching device

ICS 27.015; 29.020 ISBN 978-2-8327-0676-3

IEC 63445:2025-09(en)
IEC 63445:2025 © IEC 2025
CONTENTS
FOREWORD. 5
Introduction . 7
1 Scope . 8
2 Normative references . 8
3 Terms and definitions . 9
4 Classification . 10
4.1 Classification according to method of operation . 10
4.2 Classification according to method of interlocking . 10
4.3 Classification according to type of isolation . 10
4.4 Classification according to the method of mounting . 11
4.5 Classification according to the type of terminals . 11
4.6 According to the protection against external influences . 11
5 Characteristics of SRCSD (3.3) . 11
5.1 Rated cross-section . 11
5.1.1 General . 11
5.1.2 Rated maximum connectable cross-section with rigid conductors . 11
5.1.3 Rated minimum connectable cross-section with rigid conductors . 11
5.1.4 Rated maximum connectable cross-section with flexible conductors . 11
5.1.5 Rated minimum connectable cross-section with flexible conductors . 11
5.2 Rated leakage current (3.10) I . 11
l
5.3 Rated operational voltage . 12
5.4 Rated frequency . 12
5.5 Rated short-circuit capability . 12
5.5.1 General . 12
5.5.2 Short-circuit making capability I . 12
cm
5.5.3 Short-circuit withstand capability I . 12
cw
5.6 Switching sequence . 13
5.7 Preferred number of operating cycles . 13
5.8 Operation type . 13
5.9 Operation . 13
6 Product information . 14
6.1 Nature of information . 14
6.1.1 Identification . 14
6.1.2 Classification . 14
6.1.3 Characteristics . 14
6.2 Marking . 14
7 Standard conditions for operation in service and for installation . 14
8 Requirements for construction and operation . 14
8.1 Mechanical design . 14
8.1.1 General . 14
8.1.2 Mechanism . 14
8.1.3 Clearances, creepage distances and solid insulation . 15
8.1.4 Screws, current-carrying parts and connections . 16
8.1.5 Terminals for external conductors . 17
8.2 Protection against electric shock . 19
IEC 63445:2025 © IEC 2025
8.3 Dielectric properties . 19
8.4 Temperature-rise . 20
8.5 Mechanical and electrical endurance . 20
8.6 Performance at short-circuit currents . 20
8.7 Resistance to mechanical shock and impact . 20
8.8 Resistance to heat . 20
8.9 Resistance to abnormal heat and to fire . 20
8.10 Reliability . 20
8.11 Electromagnetic compatibility (EMC) . 21
9 Tests . 21
9.1 General . 21
9.2 Test conditions . 21
9.3 Test of indelibility of marking . 22
9.4 Test of reliability of screws, current-carrying parts and connections . 22
9.5 Test of reliability of screw-type terminals for external copper conductors . 23
9.6 Verification of protection against electric shock . 24
9.7 Test of dielectric properties . 25
9.7.1 Resistance to humidity . 25
9.7.2 Insulation resistance of the main circuit . 25
9.7.3 Dielectric strength of the main circuit . 26
9.7.4 Insulation resistance and dielectric strength of auxiliary circuits . 26
9.7.5 Capability of control circuits connected to the main circuit withstanding
high DC voltages due to insulation measurements . 27
9.7.6 Verification of impulse withstand voltages . 27
9.7.7 Verification of effective continuity between main contacts . 29
9.8 Test of temperature-rise . 29
9.8.1 Ambient air temperature . 29
9.8.2 Test procedure . 29
9.8.3 Measurement of the temperature of parts . 30
9.8.4 Temperature-rise of a part . 30
9.9 Verification of the operating characteristics . 30
9.9.1 Verification of the operation . 30
9.9.2 Verification of interlocking function . 30
9.10 Verification of mechanical and electrical endurance . 32
9.10.1 General test conditions . 32
9.10.2 Test procedure . 32
9.10.3 Condition of the SRCSD (3.3) after test . 32
9.11 Short-circuit tests . 33
9.11.1 Short-time withstand current . 33
9.11.2 Short-circuit making capacity test . 34
9.12 Verification of resistance to mechanical shock and impact . 35
9.12.1 Mechanical shock . 35
9.12.2 Mechanical impact . 36
9.13 Test of resistance to heat . 38
9.13.1 Test on complete SRCSD (3.3) . 38
9.13.2 Ball pressure test . 38
9.14 Test of resistance to abnormal heat and to fire . 39
9.15 Verification of reliability . 40
9.15.1 Climatic test . 40
IEC 63445:2025 © IEC 2025
9.15.2 Test with temperature of 40 °C . 42
9.16 Verification of withstand against ageing . 42
9.17 Electromagnetic compatibility (EMC) . 43
9.17.1 General . 43
9.17.2 Electromagnetic emission . 43
9.17.3 Electromagnetic immunity . 43
9.18 Test of resistance to rusting . 46
Annex A (normative) Test sequence and number of samples to be submitted for
certification purposes . 65
A.1 Test sequences . 65
A.2 Number of samples to be submitted for full test procedure . 66
Annex B (normative) Determination of clearances and creepage distances . 67
B.1 General . 67
B.2 Orientation and location of a creepage distance . 67
B.3 Creepage distances where more than one material is used . 67
B.4 Creepage distances split by floating conductive part . 67
B.5 Measurement of creepage distances and clearances . 67
Annex C (informative) Examples of terminal designs . 71
Bibliography . 74

Figure 1 – Example of grid connected PEI architecture . 7
Figure 2 – Operation of an SRCSD (3.3) . 13
Figure 3 – Standard test finger. 55
Figure 4 – Mechanical shock test apparatus . 55
Figure 5 – Mechanical impact test apparatus . 56
Figure 6 – Striking element for pendulum impact test apparatus . 57
Figure 7 – Mounting support for sample for mechanical impact test . 58
Figure 8 – Example of mounting an unenclosed SRCSD (3.3) for mechanical impact
test . 59
Figure 9 – Example of mounting of panel mounting type SRCSD (3.3) for the
mechanical impact test . 60
Figure 10 – Application of force for mechanical test of rail mounted SRCSD (3.3) . 61
Figure 11 – Ball-pressure test apparatus . 61
Figure 12 – Stabilizing period for reliability test . 62
Figure 13 – Reliability test cycle . 63
Figure 14 – Diagrammatic representation for glow-wire test . 64
Figure B.1 – Examples of methods of measuring creepage distances and clearances . 70
Figure C.1 – Examples of pillar terminals . 71
Figure C.2 – Examples of screw terminals and stud terminals . 72
Figure C.3 – Examples of saddle terminals . 72
Figure C.4 – Examples of lug terminals . 73

Table 1 – Immunity tests (overview) . 43
Table 2 – Performance criteria . 43
Table 3 – Voltage dip test values . 44
Table 4 – Short-interruption test values . 44
IEC 63445:2025 © IEC 2025
Table 5 – Surge test voltages . 44
Table 6 – Fast transient test values . 45
Table 7 – Requirements and position for markings and other product information . 46
Table 8 – Rated impulse withstand voltage as a function of the nominal voltage of the
installation . 48
Table 9 – Minimum clearances and creepage distances . 48
Table 10 – Test voltage of auxiliary circuits . 51
Table 11 – Test voltage for verification of rated impulse withstand voltage . 51
Table 12 – Test voltage for verifying the suitability for isolation, referred to the rated
impulse withstand voltage of the SRCSD (3.3) and the altitude where the test is carried
out . 51
Table 13 – Screw thread diameters and applied torques . 51
Table 14 – Pulling forces . 52
Table 15 – Temperature-rise values . 52
Table 16 – Values of influencing quantities . 52
Table A.1 – Test sequences. 65
Table A.2 – Number of samples for full test procedure . 66

IEC 63445:2025 © IEC 2025
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
System referencing conductor switching device

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/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 63445:2025 © IEC 2025
IEC 63445 has been prepared by subcommittee SC 23K: Electrical Energy Efficiency products,
of IEC technical committee 23: Electrical accessories. It is an International Standard.
The text of this International Standard is based on the following documents:
Draft Report on voting
23K/123/FDIS 23K/127/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.
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 63445:2025 © IEC 2025
INTRODUCTION
IEC 60364-8-82 [1] has the objective to ensure that the low-voltage electrical installation is
compatible with the existing and future ways to deliver safely and functionally the electrical
energy to current-using equipment wherever the electrical energy comes from the DSO or local
generation. IEC 60364-8-82 [1] provides requirements and recommendations that apply to low-
voltage electrical installations connected or not to a distribution network able to operate:
– with local power supplies, and/or
– with local storage units,
and that monitors and controls the energy from the locally connected sources delivering it to:
– current-using equipment, and/or
– local storage units, and/or
– distribution networks.
Such electrical installations are designated as Prosumer's electrical installations (PEIs (3.1)).
To realize such a PEI (3.1) IEC 60364-8-82 [1] specifies some parts. In case of an islandable
PEI (3.7) (principle overview out of IEC 60364-8-82:2022 [2]: Figure 1 - Example of islandable
PEI (3.7) architecture) there is a System referencing conductor switching device (3.3) (SRCSD),
identified as device 5 in Figure 1.

Figure 1 – Example of grid connected PEI architecture
The objective of this document is to define the functionality and requirements of a system
referencing conductor (3.2) switching device (SRCSD (3.3)) which is in line with the
specification given in IEC 60364-8-82 [1].
IEC 63445:2025 © IEC 2025
1 Scope
This document applies to system referencing conductor switching devices (3.3) (SRCSD) for
household and similar uses within a Prosumer’s electrical installations (PEI (3.1)).
The SRCSD (3.3) provides functions as described in IEC 60364-8-82:2022 [2], 82.8.2.2.4.
PEI (3.1) intended for operating by either being connected to a distribution network or
disconnected from the distribution network is an islandable PEI (3.7).
Intentional disconnection from and connection to the distribution network relies on the local
earthing system being switched by the SRCSD (3.3). In addition, unintentional loss of
distribution network is covered.
The SRCSD (3.3) is a single pole device intended to connect one live conductor of the power
system to an earthing arrangement.
In general the neutral conductor is earthed.
Switching the SRCSD (3.3) can change the local type of system earthing if types of system
earthing are different in island and grid connected modes.
The system referencing conductor switching device (3.3) (SRCSD) is interlocked with the
switching device for islanding (3.4) (SDFI) of a Prosumer electrical installation.
SRCSD (3.3) can be integrated in a device with other functions e.g. with a SDFI (3.4).
NOTE 1 See also IEC 60364-8-82 [1].
This document applies to SRCSD (3.3) for rated voltages not exceeding 440 V AC with rated
frequencies of 50 Hz, 60 Hz or 50/60 Hz.
NOTE 2 SRCSD (3.3) for DC operations is under consideration.
2 Normative references
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.
IEC 60364-8-82, Low-voltage electrical installations - Part 8-82: Functional aspects -
Prosumer's low-voltage electrical installations
IEC 61000-4-2:2008, Electromagnetic compatibility (EMC) - Part 4-2: Testing and measurement
techniques - Electrostatic discharge immunity test
IEC 61000-4-3, Electromagnetic compatibility (EMC) - Part 4-3 : Testing and measurement
techniques - Radiated, radio-frequency, electromagnetic field immunity test
IEC 61000-4-4, Electromagnetic compatibility (EMC) - Part 4-4: Testing and measurement
techniques - Electrical fast transient/burst immunity test
IEC 61000-4-5, Electromagnetic compatibility (EMC) - Part 4-5: Testing and measurement
techniques - Surge immunity test
IEC 63445:2025 © IEC 2025
IEC 61000-4-6, Electromagnetic compatibility (EMC) - Part 4-6: Testing and measurement
techniques - Immunity to conducted disturbances, induced by radio-frequency fields
IEC 61000-4-11, Electromagnetic compatibility (EMC) - Part 4-11: Testing and measurement
techniques - Voltage dips, short interruptions and voltage variations immunity tests for
equipment with input current up to 16 A per phase
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminology databases for use in standardization at the following
addresses:
– IEC Electropedia: available at https://www.electropedia.org/
– ISO Online browsing platform: available at https://www.iso.org/obp
3.1
PEI
prosumer's electrical installation
low-voltage electrical installation connected or not to a distribution network able to operate:
– with local power supplies, and/or
– with local storage units,
that monitors and controls the energy from the connected sources delivering it to:
– current-using equipment, and/or
– local storage units, and/or
– distribution networks
[SOURCE: IEC 60364-8-82:2022 [2], 82.3.6]
3.2
system referencing conductor
conductor that connects one live conductor of the power system to an earthing arrangement
Note 1 to entry: The live conductor connected is the neutral or the mid-point if existing, or a line conductor when
not existing.
[SOURCE: IEC 60364-8-82:2022 [2], 82.3.18]
3.3
system referencing conductor switching device
SRCSD
device connected between the system referencing conductor (3.2) and the local earthing
arrangement of the PEI (3.1)
3.4
switching device for island mode
SDFI
device dedicated to change from grid connected mode (3.5) to island mode (3.6) and from island
mode (3.6) to grid connected mode (3.5) for an islandable PEI (3.7)
Note 1 to entry: In IEC TS 62786 [3] the term used for switching device for islanding is "interface switch".
3.5
connected mode
operating mode in which the PEI (3.1) is connected to the distribution network
IEC 63445:2025 © IEC 2025
[SOURCE: IEC 60364-8-82:2022 [2], 82.3.11, modified - removed the Example]
3.6
island mode
operating mode in which the PEI (3.1) is disconnected from the distribution network
Note 1 to entry: An island mode (3.6) can be either the result of the action of automatic protections or the result of
a deliberate action.
[SOURCE: IEC 60364-8-82:2022 [2], 82.3.12]
3.7
islandable PEI
PEI (3.1) intended for operating either being connected to a distribution network or being
disconnected from the distribution network
Note 1 to entry: An islandable PEI (3.7) is in a connected mode (3.5) or an intentionally island mode (3.6).
[SOURCE: IEC 60364-8-82:2022 [2], 82.3.15]
3.8
transition time to close
time between the order to connect to local earth until the feedback that local earth connection
is established
3.9
transition time to open
time between the order to disconnect local earth until the feedback that local earth connection
is opened
3.10
rated leakage current
maximum permanent current to ground carried by the SRCSD (3.3) in island mode (3.6)
3.11
interlock
prevents simultaneous closing of SRCSD (3.3) and SDFI (3.4),
under all conditions
4 Classification
4.1 Classification according to method of operation
– Electrically controlled
– Manually (non-electrically) controlled
– Electrically and manually controlled
NOTE 1 The operation of SRCSD (3.3) is interlocked with SDFI (3.4).
NOTE 2 Ensure the operation is controlled in a coordinated way.
4.2 Classification according to method of interlocking
– Electrically
– Mechanically
4.3 Classification according to type of isolation
– Suitable for isolation
– Non-suitable for isolation
IEC 63445:2025 © IEC 2025
IEC 60364-8-82 [1] requires isolation for SRCSD (3.3).
4.4 Classification according to the method of mounting
– Panel board type SRCSD (3.3), also referred to as distribution board type.
NOTE These types can be intended to be mounted on rails e.g. IEC 60715 [4].
– Busbar mounted SRSCD (3.3).
– Integrated SRCSD (3.3).
4.5 Classification according to the type of terminals
4.5.1 SRCSD (3.3) with screw-type terminals for external copper conductors.
4.5.2 SRCSD (3.3) with screwless type terminals for external copper conductors.
4.5.3 SRCSD (3.3) with flat quick-connect terminals for external copper conductors.
4.6 According to the protection against external influences
4.6.1 Enclosed-type SRCSD (3.3) (not requiring an appropriate enclosure).
4.6.2 Unenclosed-type SRCSD (3.3) (for use with an appropriate enclosure).
5 Characteristics of SRCSD (3.3)
5.1 Rated cross-section
5.1.1 General
The cross section of a SRCSD (3.3) should be in line with the required cross-section for the
local source.
5.1.2 Rated maximum connectable cross-section with rigid conductors
Maximum connectable cross-section for rigid conductor.
5.1.3 Rated minimum connectable cross-section with rigid conductors
Minimum connectable cross-section for rigid conductor.
5.1.4 Rated maximum connectable cross-section with flexible conductors
Maximum connectable cross-section for flexible conductor.
5.1.5 Rated minimum connectable cross-section with flexible conductors
Minimum connectable cross-section for flexible conductor.
5.2 Rated leakage current (3.10) I
l
The SRCSD (3.3) operates without a voltage difference but shall be capable to carry
permanently its rated leakage current (3.10). The preferred rated leakage current (3.10) values
are 1 A, 3 A, 5 A, 10 A, 16 A, 20 A, 32 A, 63 A, 80 A, 100 A, 125 A with a minimum value of 1
A.
NOTE The rated current of the SRCSD (3.3) is usually the maximum leakage current to ground allowed in island
mode (3.6).
IEC 63445:2025 © IEC 2025
5.3 Rated operational voltage
The rated operational voltage of an SRCSD (3.3) is the value of voltage, assigned by the
manufacturer, to which its performance is referred. Standard values of rated operational voltage
are : 120 V – 230 V – 400 V.
5.4 Rated frequency
The rated frequency of an SRCSD (3.3) is the power frequency for which the SRCSD (3.3) is
designed and to which the values of the other characteristics correspond.
Standard values of rated frequency: 50 Hz – 60 Hz – 50/60 Hz.
5.5 Rated short-circuit capability
5.5.1 General
The SRCSD (3.3) operates without a voltage difference but shall be capable to make and carry
its rated short-circuit capability.
NOTE 1 Rated short circuit capability of the SRCSD (3.3) is usually calculated depending on the maximum short
circuit current delivered by the source(s) used in island mode (3.6).
NOTE 2 Rated short circuit capability of the SRCSD (3.3) is usually between one and two times the rated current
of sources using power converters, when in island mode (3.6).
5.5.2 Short-circuit making capability I
cm
In case SRCSD (3.3) is closing to island mode (3.6) on a phase to ground short circuit.
5.5.3 Short-circuit withstand capability I
cw
In case a phase to ground short circuit occurs while SRCSD (3.3) is closed, the preferred
withstand capability values are, for a preferred duration of 500 ms, 1 s or 5 s (see IEC 60364-
4-41:2005 [5], 411):
– 16 A
– 25 A
– 32 A
– 63 A
– 100 A
– 125 A
– 160 A
– 250 A
– 400 A
– 630 A
– 800 A
– 1 000 A
– 1 250 A
– 1 600 A
– 3 kA
– 4,5 kA
– 6 kA
– 10 kA
IEC 63445:2025 © IEC 2025
– 20 kA
– 25 kA
5.6 Switching sequence
– Closing time
– Opening time
IEC 60364-8-82 [1] recommends that in case of transition between the modes, operation without
reference the system to earth does not exceed 5 s.
5.7 Preferred number of operating cycles
– 4 000 (minimum number of operating cycles),
– 6 000,
– 12 000,
– 25 000
5.8 Operation type
The SRSCD (3.3) shall have two stable states. After loss of supply the position of the switch
shall not change.
5.9 Operation
The operation of the SRCSD (3.3) is shown in Figure 2.
Operation to switch from connected mode (3.5) to islanding mode. The SRCSD (3.3) shall be
closed after the SDFI (3.4) opens.
Operation to switch from islanding mode to connected mode (3.5). The SRCSD (3.3) shall be
opened before the SDFI (3.4) closes.
Unless the SRCSD (3.3) is integrated in one device with an SDFI (3.4), SRCSD (3.3) shall be
provided with the required means to interlock (3.11) with a SDFI (3.4), together with installation
instructions.
Figure 2 – Operation of an SRCSD (3.3)
IEC 63445:2025 © IEC 2025
6 Product information
6.1 Nature of information
6.1.1 Identification
a) Manufacturer's name or trade mark;
b) Type designation or serial number;
c) Reference to the product standard.
6.1.2 Classification
a) Method of operation (see 4.1);
b) Method of interlocking (see 4.2);
c) Type of isolation (see 4.3);
d) Method of mounting (see 4.4);
e) Type of terminals (see 4.5).
6.1.3 Characteristics
a) Rated short-circuit maki
...