EN IEC 61643-41:2025

SLOVENSKI STANDARD
01-oktober-2025
Nizkonapetostne naprave za zaščito pred prenapetostnimi udari - 41. del: Naprave
za zaščito pred prenapetostnimi udari za nizkonapetostne DC napajalne sisteme -
Zahteve in preskusne metode (IEC 61643-41:2025)
Low-voltage surge protective devices - Part 41: Surge protective devices connected to
DC low-voltage power systems - Requirements and test methods (IEC 61643-41:2025)
Überspannungsschutzgeräte für Niederspannung – Teil 41: Überspannungsschutzgeräte
für den Einsatz in Niederspannungs-Gleichstromnetzen - Anforderungen und
Prüfverfahren (IEC 61643-41:2025)
Parafoudres basse tension - Partie 41: Parafoudres connectés aux réseaux basse
tension en courant continu - Exigences et méthodes d’essai (IEC 61643-41:2025)
Ta slovenski standard je istoveten z: EN IEC 61643-41:2025
ICS:
29.120.50 Varovalke in druga Fuses and other overcurrent
nadtokovna zaščita protection devices
29.240.10 Transformatorske postaje. Substations. Surge arresters
Prenapetostni odvodniki
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN IEC 61643-41

NORME EUROPÉENNE
EUROPÄISCHE NORM August 2025
ICS 29.240.10
English Version
Low-voltage surge protective devices - Part 41: Surge protective
devices connected to DC low-voltage power systems -
Requirements and test methods
(IEC 61643-41:2025)
Parafoudres basse tension - Partie 41: Parafoudres Überspannungsschutzgeräte für Niederspannung - Teil 41:
connectés aux réseaux basse tension en courant continu - Überspannungsschutzgeräte für den Einsatz in
Exigences et méthodes d'essai Niederspannungs-Gleichstromnetzen - Anforderungen und
(IEC 61643-41:2025) Prüfverfahren
(IEC 61643-41:2025)
This European Standard was approved by CENELEC on 2025-07-15. 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 61643-41:2025 E

European foreword
The text of document 37A/426/FDIS, future edition 1 of IEC 61643-41, prepared by SC 37A "Low-
voltage surge protective devices" of IEC/TC 37 "Surge arresters" was submitted to the IEC-CENELEC
parallel vote and approved by CENELEC as EN IEC 61643-41:2025.
The following dates are fixed:
• latest date by which the document has to be implemented at national (dop) 2026-08-31
level by publication of an identical national standard or by endorsement
• latest date by which the national standards conflicting with the (dow) 2028-08-31
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 is read in conjunction with EN IEC 61643-01.
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
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 61643-41:2025 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 62368-1:2018 NOTE Approved as EN IEC 62368-1:2020 (not modified) + A11:2020
ISO 4892-1 NOTE Approved as EN ISO 4892-1
ISO 4892-2 NOTE Approved as EN ISO 4892-2
IEC 61643-41 ®
Edition 1.0 2025-05
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
Low-voltage surge protective devices –
Part 41: Surge protective devices connected to DC low-voltage power systems –
Requirements and test methods
Parafoudres basse tension –
Partie 41: Parafoudres connectés aux réseaux basse tension en courant continu –
Exigences et méthodes d’essai
ICS 29.240.10  ISBN 978-2-8327-0447-9

IEC 61643-41:2025-05(en-fr)
– 2 – IEC 61643-41:2025 © IEC 2025
CONTENTS
FOREWORD . 3
INTRODUCTION . 5
1 Scope . 6
2 Normative references . 6
3 Terms, definitions and abbreviated terms . 7
4 Classification . 7
5 Void . 7
6 Marking and other product information . 7
7 Service conditions . 8
8 Requirements . 8
9 Tests . 9
Annex AA (normative) Application of annexes from IEC 61643-01 . 20
Annex BB (normative) Test voltages for SPDs – U . 21
test
Annex CC (normative) TOV test values for DC power systems . 23
Annex DD (informative) DC power systems . 25
Bibliography . 31

Figure 100 – Procedure for sample preparation for dedicated overstress test . 16
Figure 101 – Example of a test circuit for the TOV tests . 18
Figure 102 – Timing diagram for the TOV tests . 18
Figure DD.1 – TT DC distribution system . 25
Figure DD.2 – TT DC distribution system with a mid-point. 26
Figure DD.3 – TN-S DC distribution system . 26
Figure DD.4 – TN-S DC distribution system with a mid-point . 27
Figure DD.5 – TN-C DC distribution system with a mid-point . 27
Figure DD.6 – TN-C DC distribution system. 28
Figure DD.7 – TN-C-S DC distribution system . 28
Figure DD.8 – TN-C-S DC distribution system with a mid-point . 29
Figure DD.9 – IT DC distribution system . 29
Figure DD.10 – IT DC distribution system with a mid-point . 30

Table 100 – Type test requirements for SPDs . 10
Table 101 – Prospective short circuit current and time constant . 14
Table AA.1 – Application of annexes from IEC 61643-01 . 20
Table BB.1 – Test voltage values . 22
Table CC.1 – TOV test values for DC power systems . 23
Table CC.2 – Prospective short-circuit currents for TOV tests . 24

IEC 61643-41:2025 © IEC 2025 – 3 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
LOW-VOLTAGE SURGE PROTECTIVE DEVICES –

Part 41: Surge protective devices connected to DC low-voltage power
systems – Requirements and test methods

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 61643-41 has been prepared by subcommittee 37A: Low-voltage surge protective devices,
of IEC technical committee 37: Surge arresters. It is an International Standard.
This first edition only contains the specific requirements for SPDs for DC applications.
This International Standard is to be used in conjunction with IEC 61643-01.
The requirements of this document supplement, modify or replace certain of the general
requirements contained in IEC 61643-01 and shall be read and applied together with the latest
edition of IEC 61643-01, as indicated by the undated normative reference in Clause 2 of this
document.
Numbering of clauses follows the numbering of IEC 61643-01, but, dependent on the application
of clauses from IEC 61643-01, does not necessarily follow sequentially.

– 4 – IEC 61643-41:2025 © IEC 2025
If a clause in IEC 61643-01 is not explicitly called up or referred to in this document, then this
clause does not apply to SPDs covered by this document. Any instructions in this document
calling up clauses from IEC 61643-01 are written in Italic type.
NOTE In other words, if e.g. Clause 4 is called up in this document all subclauses of Clause 4 of IEC 61643-01 are
applied without modification. But, if e.g. some modifications are required on subclauses of Clause 9 of IEC 61643-01,
then the relevant second level subclauses of IEC 61643-01 (e.g. 9.3, 9.5 etc.) are called up separately and it is
indicated how they are applied.
The numbering of additional subclauses to IEC 61643-01 in this document starts with the
number 100 in the last section of the subclause added (see e.g. 4.100). The numbering of
additional tables and figures to IEC 60643-01 in this document starts with the number 100.
The text of this International Standard is based on the following documents:
Draft Report on voting
37A/426/FDIS 37A/430/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 parts of the IEC 61643 series can be found, under the general title Low-voltage
surge protective devices, on the IEC website.
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 61643-41:2025 © IEC 2025 – 5 –
INTRODUCTION
It has been assumed in the drafting of this International Standard that the execution of its
provisions is entrusted to appropriately qualified and experienced persons.
This document recognizes the internationally accepted level of protection against hazards such
as electrical, mechanical, thermal, fire and radiation of SPDs when operated as in normal use
taking into account the manufacturer's instructions. It also covers abnormal situations that can
be expected in practice.
This document takes into account the requirements of IEC 60364 as far as possible so that
there is compatibility with the wiring rules when the SPD is connected to the supply mains.
However, national wiring rules may differ.
If the intended applications of an SPD are covered by different parts of the IEC 61643-x1 series,
all relevant parts shall be applied, as far as is reasonable.
This part of the IEC 61643 series addresses safety and performance tests for surge protective
devices (SPDs) for DC applications in conjunction with IEC 61643-01.
This document addresses T1 SPD, T2 SPD and T3 SPD according to IEC 61643-01.
IEC 61643-12 addresses the general selection and application principles of SPDs, but focusing
on SPDs for AC low-voltage power systems. A separate standard IEC 61643-42 is planned,
which is intended to specifically address selection and application principles for SPDs for DC
low-voltage power systems.
– 6 – IEC 61643-41:2025 © IEC 2025
LOW-VOLTAGE SURGE PROTECTIVE DEVICES –

Part 41: Surge protective devices connected to DC low-voltage power
systems – Requirements and test methods

1 Scope
This document, together with IEC 61643-01, is applicable to devices for surge protection
against indirect and direct effects of lightning or other transient overvoltages.
These devices are intended to be connected to DC power circuits and equipment rated up to
1 500 V DC. Performance and safety requirements, tests and ratings are specified in this
document. These devices contain at least one nonlinear component and are intended to limit
surge voltages and divert surge currents.
The test requirements provided by this document are based on the assumption that the SPD is
connected to a DC power circuit fed by a power source providing a linear voltage-current
characteristic. When the SPD is to be connected to a different kind of source, careful
consideration is required. This mainly applies with regard to system and fault conditions to be
expected in such a system (e.g. expected short circuit current, TOV-stresses).
This document can apply for railway applications, when related product standards do not exist
for that area or for certain applications.
Based on a risk assessment it might not be necessary to apply all requirements of this document
to SPDs designed for specific power applications only, e.g. circuits with a low power capability,
circuits supplied by nonlinear sources, circuits with protective separation from the utility supply.
NOTE 1 More information on risk assessment is provided in IEC Guide 116.
SPDs for PV applications are not covered by this document.
NOTE 2 Such SPDs for PV applications are covered by IEC 61643-31.
NOTE 3 Other exclusions based on national regulations are possible.
2 Normative references
For the purposes of this document the normative references given in IEC 61643-01 with the
following additions apply.
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 61643-01, Low-voltage surge protective devices – Part 01: General requirements and test
methods
IEC 61643-41:2025 © IEC 2025 – 7 –
3 Terms, definitions and abbreviated terms
Clause 3 of IEC 61643-01 applies.
4 Classification
Clause 4 of IEC 61643-01 applies with the following additions:
4.13 End-of-life mode of the SPDA
4.13 of IEC 61643-01 applies with the following additions:
For SPDAs for DC power circuits fed by a power source providing a linear voltage-current
characteristic, only the open circuit mode according to 4.13.1 of IEC 61643-01 is applicable.
NOTE A short circuiting SPD, when used with its required SPD disconnectors (SPDA), fulfils the conditions to be
classified open circuit mode (OCM).
5 Void
6 Marking and other product information
Clause 6 of IEC 61643-01 applies with the following additions.
6.2 List of items
6.2 of IEC 61643-01 applies with the following additions:
The following information from the list of items in 6.2 of IEC 61643-01 and any additional items
specified shall be provided as required below.
Item 20) from 6.2 of IEC 61643-01 applies with the following addition:
This includes information e.g. on the separation of the DC system from any upstream AC or DC
system and their interconnection as related to system earthing.
Item 25) from 6.2 of IEC 61643-01 applies with the following addition:
The AC and DC values or a curve shall be provided in accordance with 9.3.3.1.
6.2.100 Markings which are required on the body, or permanently attached to the body,
of the SPD:
6.2.100.1 Markings which shall be visible after installation:
Items 1) to 3) from 6.2 of IEC 61643-01 shall be visible after installation.
For portable SPDs and for pluggable SPDs it is sufficient that above markings are visible in the
unplugged condition. This does not apply to the minimum marking requirements according to
6.1 of IEC 61643-01.
6.2.100.2 Markings which are not required to be visible after installation:
Items 4) to 8) from 6.2 of IEC 61643-01 shall be visible on the SPD but are not required to be
visible after installation.
– 8 – IEC 61643-41:2025 © IEC 2025
6.2.101 Information to be provided by the manufacturer:
Items 1) to 40) from 6.2 of IEC 61643-01 shall be provided, if applicable, and as amended
according to 6.2 of this document.
6.2.102 Information which shall be provided by the manufacturer for type testing, as
applicable:
Items 41) to 43) from 6.2 of IEC 61643-01 shall be provided.
7 Service conditions
Clause 7 of IEC 61643-01 applies:
8 Requirements
Clause 8 of IEC 61643-01 applies with the following additions and exemption:
8.3 Electrical requirements
8.3 of IEC 61643-01 applies with the following additions and exemption:
8.3.6.4 Dedicated overstress behaviour
8.4.6.4 from IEC 61643-01 applies with the following exemption:
This test is not performed on SPD’s modes of protection classified according to 4.14.1.4 of IEC
61643-01.
8.3.9 Behaviour under temporary overvoltages
8.3.9 of IEC 61643-01 applies with the following additions:
SPD shall either withstand the overvoltages caused by faults or disturbances in the high or low
voltage system or fail in a manner not creating a hazard.
8.3.9.100 General requirements for TOV tests
Compliance is checked by the test in accordance with 9.3.9.100 and the following clauses,
depending on the kind of TOV.
For this test, Annex CC is to be considered.
8.3.9.101 TOVs caused by DC low voltage system faults (earth faults and short circuits)
Compliance is checked by the test in accordance with 9.3.9.100 and 9.3.9.101.
8.3.9.102 TOVs caused by DC low voltage system faults (loss of mid-point connection)
Compliance is checked by the test in accordance with 9.3.9.100 and 9.3.9.102.

IEC 61643-41:2025 © IEC 2025 – 9 –
8.3.9.103 TOVs caused by faults in the high (medium) voltage AC system transferred to
a DC system, which is derived from a low-voltage AC TT- or IT-system without
separation
Compliance is checked by the test in accordance with 9.3.9.100 and 9.3.9.103 and according
to items 20) and 30) from 6.2 of IEC 61643-01 as amended according to 6.2 of this document.
This requirement does not apply to SPDs which shall only be used in a DC system with
separation from the AC system or when the AC system is a TN system.
8.3.9.104 TOVs caused by faults in the high (medium) voltage DC system transferred to
a DC TT- or IT-system with common earthing
Compliance is checked by the test in accordance with 9.3.9.100 and 9.3.9.104 and according
to items 20) and 30) from 6.2 of IEC 61643-01 as amended according to 6.2 of this document.
This requirement does not apply to SPDs which shall only be used in a DC system without
common high (medium) voltage DC system earthing.
9 Tests
Clause 9 of IEC 61643-01 applies with the following additions:
9.1 Type testing procedures
9.1 of IEC 61643-01 applies with the following additions:
9.1.1 General
9.1.1 of IEC 61643-01 applies with the following additions:
The test voltage U shall be selected from Annex BB based on the information given by the
test
manufacturer according to 6.2.101 and according to items 9), 10), 20) and 21) from 6.2 of
IEC 61643-01.
For SPDs with a designated mid-point connection, which may be applied in systems without
distributed mid-point according to the manufacturer's instructions, separate testing is required
for the L-PE mode of protection with the mid-point being unconnected.
Table 100 shows all tests and for which tests the tissue paper and/or the metallic screen are
required.
Annex AA provides information which Annexes from IEC 61643-01 apply to SPDs for DC low-
voltage power systems.
Annex DD provides general information about DC power system grounding and connection
naming.
– 10 – IEC 61643-41:2025 © IEC 2025
Table 100 – Type test requirements for SPDs
SPD assembly SPD
SPD Design
External
classified
Require- Tissue Metallic
outdoor
SPD
dis-
T1 T2 T3
Test Test clause ment paper screen
and
connec- e)
SPD SPD SPD
voltage combi- voltage
M-PE
clause used used
inacces-
a) OCM SCM
tors
limiting nation switching
f)
sible
Marking and product
9.2 6 / 8.2 - - - M M M M M M M M M M
information
Protection against direct
9.3.1 8.3.1 - - - M M M M M M M M M M
contact
Continuous current 9.3.2 8.3.2 - - - M M M M M M M M M M
Protective conductor current 9.3.3 8.3.3 - - - A A A A A A A A A A
Measured limiting voltage 9.3.4 8.3.4 - - - M M M M M M M M M M
Residual voltage 9.3.4.2 - - - M M - M M M M M M M
Front-of-wave sparkover
9.3.4.3 - - - A A - A A - A A A A
voltage
Limiting voltage with
9.3.4.4 - - - - - M M M M M
...