EN 61643-31:2019

SLOVENSKI STANDARD
01-september-2019
Nadomešča:
SIST EN 50539-11:2013
SIST EN 50539-11:2013/A1:2014
Nizkonapetostne naprave za zaščito pred prenapetostnimi udari - 31. del: Naprave
za zaščito pred prenapetostnimi udari za posebno uporabo vključno z enosmernim
tokom - Zahteve in preskusne metode za SPD za fotonapetostne inštalacije
Low-voltage surge protective devices - Part 31: Surge protective devices for specific use
including d.c. - Requirements and test methods for SPDs for photovoltaic installations
Ta slovenski standard je istoveten z: EN 61643-31:2019
ICS:
27.160 Sončna energija Solar energy engineering
29.120.50 Varovalke in druga Fuses and other overcurrent
medtokovna zaščita protection devices
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN 61643-31

NORME EUROPÉENNE
EUROPÄISCHE NORM
May 2019
ICS 29.240; 29.240.10 Supersedes EN 50539-11:2013
English Version
Low-voltage surge protective devices - Part 31: Requirements
and test methods for SPDs for photovoltaic installations
(IEC 61643-31:2018 , modified)
Parafoudres basse tension - Partie 31: Parafoudres pour Überspannungsschutzgeräte für Niederspannung - Teil 31:
usage spécifique y compris en courant continu - Exigences Anforderungen und Prüfungen für
et méthodes d'essai des parafoudres pour installations Überspannungsschutzgeräte in Photovoltaik-Installationen
photovoltaïques (IEC 61643-31:2018 , modifiziert)
(IEC 61643-31:2018 , modifiée)
This European Standard was approved by CENELEC on 2018-02-14. 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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden,
Switzerland, Turkey 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
© 2019 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN 61643-31:2019 E
European foreword
The text of document 37A/306/FDIS, future edition 1 of IEC 61643-31, 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 61643-31:2019.
A draft amendment, which covers common modifications to IEC 61643-31, was prepared by CLC/TC 37A
"Low-voltage surge protective devices" and approved by CENELEC.
The following dates are fixed:
• latest date by which this document (dop) 2019-11-03
has to be implemented at national
level by publication of an identical
national standard or by
endorsement
• latest date by which the national (dow) 2022-05-03
standards conflicting with this
document have to be withdrawn
Clauses, subclauses, notes, tables, figures and annexes which are additional to those in IEC 61643-31:2019
are prefixed “Z”.
includes also guidance for verification of conformity for products already tested according
EN 50539-11:2013.
The main changes with respect of EN 50539-11:2013 are the complete restructuring and improvement of the
test procedures and test sequences.
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 mandate given to CENELEC by the European Commission and
the European Free Trade Association, and supports essential requirements of EU Directive(s).
For the relationship with EU Directive(s) see informative Annex ZZ, which is an integral part of this
document.
Endorsement notice
The text of the International Standard IEC 61643:2018 was approved by CENELEC as a European Standard
with agreed common modifications.
COMMON MODIFICATIONS
Modify as follows:
Through the Replace all IEC 61643 references by EN 61643
complete
document:
Replace all IEC references by EN when relevant standard is listed in either the
Normative reference or in the Bibliography sections.
Foreword Add to the Foreword the following:
This standard covers the principle elements and objectives for electrical equipment
designed for use within certain voltage limits (LVD - 2014/35/EU) and for
electromagnetic compatibility (EMCD - 2014/30/EU).
Introduction Delete the last sentence in the Introduction.
th
Scope Modify the 5 paragraph to read:
SPDs with separate input and output terminal(s) that contain specific series impedance
between these terminal(s) (so called two-port SPDs according to EN 61643-11) are not
covered. As test class III in EN 61643-11 was primarily developed to cover two-port
SPDs, SPDs tested according to this test class are not intended to be used in PV-
systems.
3.1.19 Add the following note:
NOTE  EN 62475 provides the current impulse definitions of front time, time to half values and waveshape.
5.3 Replace 5.3 by the following:
Types 1 and 2 SPDs- Class I and II tests
Information required for class I and class II tests is given in Table Z1.
Table Z1 – Tests of types 1 and 2 SPDs
Type of SPD Tests Required information
Type 1 Class I Iimp
Type 2 Class II In
6.5 Add new requirement:
6.5.4 Vibration and shock
Information on vibration and shock tests for transportation and special applications can
be found in Annex ZB of EN 61643-11.
7.4.4.2.2 Replace:
in less than 60 s when PV4 with ISCPV or DC3 with 2,7 times ISCPV is applied. During the
tests when DC with 2,7 times I is applied, the fuse for detection shall not operate;
3 SCPV
in less than 5 min when DC3 with a prospective short-circuit current of equal to ISCPV is
applied.
by:
in less than 20 s when PV with I or DC with 2,7 times I is applied. During the
4 SCPV 3 SCPV
tests when DC3 with 2,7 times ISCPV is applied, the fuse for detection shall not operate;
in less than 1 min when DC with a prospective short-circuit current of equal to I is
3 SCPV
applied.
7.4.4.3.2 Replace:
In less than 60 s during the test when PV4 with a prospective short-circuit current of
I is applied;
SCPV
by:
In less than 20 s during the test when PV with a prospective short-circuit current of
ISCPV is applied;
Annex ZA Add Annex ZA (See annexes)
Annex ZB Add Annex ZB (See annexes)
Annex ZZ Add Annex ZZ (See annexes)
Bibliography Modify Bibliography (See Annexes)

Add the following annexes:
Annex ZA
(informative)
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.cenelec.eu.
Publication Year Title EN/HD Year

IEC 60060-1 2010 High-voltage test techniques - Part 1: General EN 60060-1 2010
definitions and test requirements

IEC 60112 2003 Method for the determination of the proof and EN 60112 2003
the comparative tracking indices of solid
insulating materials
IEC 60529 1989 Degrees of protection provided by enclosures EN 60529 1991
(IP Code)
IEC 60664-1 2007 Insulation coordination for equipment within EN 60664-1 2007
low-voltage systems - Part 1: Principles,
requirements and tests
IEC 61000 series Electromagnetic compatibility (EMC) EN 61000 series

IEC 61000-6-1 2005 Electromagnetic compatibility (EMC) – Part 6-1: EN 61000-6-1 2007
Generic standards – Immunity for residential,
commercial and light-industrial environments

IEC 61000-6-3 2006 Electromagnetic compatibility (EMC) – Part 6-3: EN 61000-6-3 2007
Generic standards – Emission standard for
residential, commercial and light-industrial
environments
IEC 60068-2-78 2012 Environmental testing - Part 2-78: Tests - Test EN 60068-2-78 2013
Cab: Damp heat, steady state
IEC 61180-1 1992 High-voltage test techniques for low-voltage EN 61180-1 1994
equipment - Part 1: Definitions, test and
procedure requirements
IEC 60364-5-51 - Electrical installation of buildings – Part 5-51: HD 60364-5-51 2009
Selection and erection of electrical equipment;
Common rules
IEC 61643-11 2011 Low-voltage surge protective devices –Part 11: EN 61643-11 2012
Surge protective devices connected to low-
+ A11 2018
voltage power systems –Requirements and test
methods
IEC 62475 - High-current test techniques - Definitions and EN 62475 2010
requirements for test currents and measuring
systems
Annex ZB
(normative)
Reduced test procedure
This annex addresses the number of samples to be submitted and test sequence to be applied for
verification of conformity for products already tested according EN 50539-11:2013.
The simplified test procedure according to Table ZB.1 may then be applied for verification of
conformity.
For new products complete type tests and samples according to Clause 7 are required.
Table ZB.1 - Simplified test procedure for SPDs already complying with EN 50539-11
Test
Test description Subclause Testing required
sequence
a
1 Identification and marking 6.1.1 / 6.1.2 / 7.2 Yes
Mounting 6.3.1 No
Terminals and connections 6.3.2 / 6.3.3 No
b
Testing for protection against direct contact 6.2.1 Yes
Environment, IP code 6.4 No
Residual current 6.2.2 / 7.4.1 No
Continuous current 6.2.8 / 7.4.6 Yes
Operating duty test 6.2.4 / 7.4.2 No
Operating duty test for test classes I and II 7.2.3.2 / 7.4.2.3 / No
7.4.2.4
Additional duty test for test class I 7.4.2.5 No
Thermal stability 6.2.5.3 / 7.4.3.2 Yes
Air clearances and creepage distances 6.6.3.4 / 7.5.1 No
Ball pressure test 6.4 No
Resistance to abnormal heat and fire 6.4 No
Tracking resistance 6.4 No
2 Voltage Protection level 6.2.3 No
3 Insulation resistance 6.2.6 No
Dielectric withstand 6.2.7 / 7.4.5 No
3a
See below - only if applicable
Mechanical strength 6.3.5 No
Temperature withstand 6.2.5 / 7.4.3.1 No
3b See below - only if applicable
4 Heat resistance 6.4 No
c d
5 SPD failure mode test 6.2.5.4 / 7.4.4 Yes
6 Live test under damp heat 7.6.1 No
7 Total discharge current test for multipole SPDs 6.2.9 No
Additional tests for one-port-SPDs with separate input / output terminals
3b Rated load current 6.5.1 / 7.7.1.1 No
Additional tests for outdoor use SPDs
Environmental tests for outdoor SPDs 6.5.2 / 7.7.2 No
Additional tests for SPDs with separate isolated circuits
3a Isolation between separate circuits 6.5.3 / 7.4.5 No
a
This is related to 6.1.1 only.
b
This is related to SPDs having a UCPV equal to or below 120 V only.
c
For this test sequence more than one set of samples may be needed.
d
This is related to combination SPDs only (no additional test for other types of SPDs).
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 Annex I of Directive 2014/35/EU
[2014 OJ L96]
Clause(s) / sub-clause(s)
Safety objectives of Directive
Remarks / Notes
2014/35/EU
of this EN
(1)(a) Clauses 6.1, 6.3.1
Clause 7.3
(1)(b) Clause 6.1
(1)(c) Clauses 1, 2, 3, 4, 5 and refer to 2a)

to 2d) below and 3a) to 3c) below
(2)(a) Clause 5.5, 6.2.1, 6.2.2

Clause 7.1, 7.2, 7.4.1, 7.2.1 table 5
and table 4 pass criteria c, e, h, I, j,
and clause 8
(2)(b) Clauses 6.5.1, 6.2.5.3, 6.2.5, 6.2.4,
6.5.1
Clauses 7.1, 7.2, 7.4.2, 7.4.3.2,
7.4.3, 7.4.4, 7.7.1, 8
(2) (c) Clauses 6.4.3.1, 6.4.3.2
Clause 8
(2)(d) Clauses 6.3.4, 6.2.6, 6.2.7, 6.5.2
Clauses 7.1, 7.2, 7.5.1, 7.5.2, 7.4.5,
7.7.2, 8
(3)(a) Clause 6.3.5
Clause 7.1, 7.2, 8
(3)(b) Clauses 6.4.2, 6.4.1, 6.5.2
Clauses 7.1, 7.2, 7.6.1, 7.6.2, 7.7.2,
Clause 8.5.2, 8.5.3, 8.3.5.1
(3)(c) Clauses 6.2.5
Clauses 7.1, 7.2, 7.4.3, 7.4.4, 8

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.
Bibliography
For the following references,
Replace:
IEC 60950:1991, Information technology equipment-Safety
by:
EN 60950-1, Information technology equipment – Safety – Part 1: General requirements (IEC 60950-1)
Replace:
ISO 4892-2, Plastics - Methods of exposure to laboratory light sources - Part 2: Xenon-arc lamps
ISO 4892-1, Plastics - Methods of exposure to laboratory light sources - Part 1: General guidance
ISO 4628-3, Paints and varnishes - Evaluation of degradation of coatings - Designation of quantity and size
of defects, and of intensity of uniform changes in appearance - Part 3: Assessment of degree of rusting
by:
EN ISO 4892-2, Plastics – Methods of exposure to laboratory light sources – Part 2: Xenon-arc lamps
(ISO 4892-2)
EN ISO 4892-1:2000, Plastics – Methods of exposure to laboratory light sources – Part 1: General guidance
(ISO 4892-1)
EN ISO 4628-3, Paints and varnishes – Evaluation of degradation of coatings – Designation of quantity and
size of defects, and of intensity of uniform changes in appearance – Part 3: Assessment of degree of rusting
(ISO 4628-3)
Add the following references:
EN 50521:2008, Connectors for photovoltaic systems - Safety requirements and tests
EN 60068-2-11:1999, Environmental testing – Part 2: Tests – Test Ka: Salt mist (IEC 60068-2-11:1981)
EN 60068-2-14:2009, Environmental testing – Part 2-14: Tests - Test N: Change of temperature
(IEC 60068-2-14:2009)
EN 60068-2-30:2005, Environmental testing – Part 2-30: Tests – Test Db: Damp heat, cyclic (12 h + 12 h
cycle) (IEC 60068-2-30:2005)
EN 60099-4:2004, Surge arresters – Part 4: Metal-oxide surge arresters without gaps for a.c. systems
(IEC 60099-4:2004, mod.)
EN 60112:2003, Method for the determination of the proof and the comparative tracking indices of solid
insulating materials (IEC 60112:2003)
EN 60228: 2005, Conductors of insulated cables (IEC 60228: 2004)
EN 60947-1:2007, Low voltage switchgear and controlgear – Part 1: General rules (IEC 60947-1:2007)

EN 60947-5-1:2004, Low-voltage switchgear and controlgear – Part 5-1: Control circuit devices and
switching elements – Electromechanical control circuit devices (IEC 60947-5-1:2003)
EN 60999-1:2000, Connecting devices – Electrical copper conductors – Safety requirements for screw-type
and screwless-type clamping units – Part 1: General requirements and particular requirements for clamping
units for conductors from 0,2 mm² up to 35 mm² (included) (IEC 60999-1:1999)
1)
EN 60695-2-11:2001 , Fire hazard testing – Part 2-11: Glowing/hot wire based test methods – Glow-wire
flammability test method for end-product (IEC 60695-2-11:2000)
EN 62305 (all parts), Protection against lightning (IEC 62305 (all parts))
HD 21 (all parts), Polyvinyl chloride insulated cables of rated voltages up to and including 450/750 V
(IEC 60227 (all parts), mod.)
HD 60364-4-443:2001, Electrical installations of buildings – Part 4-44: Protection for safety – Protection
against voltage disturbances and electromagnetic disturbances – Clause 443: Protection against
overvoltages of atmospheric origin or due to switching (IEC 60364-4-44:2001/A1:2003, mod.)
HD 60364-5-51:2009, Electrical installations of buildings – Part 5-51: Selection and erection of electrical
equipment - Common rules (IEC 60364-5-51:2005, mod.)
HD 60364-5-534:2008, Low-voltage electrical installations – Part 5-53: Selection and erection of electrical
equipment – Isolation, switching and control – Clause 534: Devices for protection against overvoltages
(IEC 60364-5-53:2001/A1:2002 (CLAUSE 534), mod.)
IEC 60245 (all parts), Rubber insulated cables – Rated voltages up to and including 450/750 V
UTE C 61-740-51, Juin 2009, Parafoudres basse tension – Partie -51: Parafoudres connectés aux
installations de générateurs photovoltaïques – Exigences et essays
EN 61643-32:2016, Low-voltage surge protective devices - Surge protective devices for specific use
including d.c.- Part 32: Selection and application principles – SPDs connected to photovoltaic installations
———————
1)
Superseded by EN 60695-2-11:2014 (IEC 60695-2-11:2014).
IEC 61643-31 ®
Edition 1.0 2018-01
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Low-voltage surge protective devices –

Part 31: Requirements and test methods for SPDs for photovoltaic installations

Parafoudres basse tension –
Partie 31: Parafoudres pour usage spécifique y compris en courant continu –

Exigences et méthodes d'essai des parafoudres pour installations

photovoltaïques
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 29.240.01; 29.240.10 ISBN 978-2-8322-5211-6

– 2 – IEC 61643-31:2018 © IEC 2018
CONTENTS
FOREWORD . 5
INTRODUCTION . 7
1 Scope . 8
2 Normative references . 8
3 Terms, definitions, acronyms and symbols . 9
3.1 Terms and definitions . 9
3.2 Acronyms / Symbols . 16
4 Service conditions . 17
4.1 Voltage . 17
4.2 Air pressure and altitude . 17
4.3 Temperatures . 17
4.4 Humidity . 18
5 Classification . 18
5.1 General . 18
5.2 SPD design . 18
5.3 Class I, II and III tests . 18
5.4 Location . 18
5.4.1 Indoor . 18
5.4.2 Outdoor . 18
5.5 Accessibility . 18
5.5.1 Accessible . 18
5.5.2 Inaccessible . 18
5.6 Disconnectors (including overcurrent protection) . 18
5.7 Degree of protection provided by enclosures according to IP-code of
IEC 60529 . 19
5.8 Temperature and humidity range . 19
5.9 Multipole SPD . 19
5.10 SPD failure mode . 19
5.11 PV earthing system . 19
6 Requirements . 19
6.1 General requirements . 19
6.1.1 Identification . 19
6.1.2 Marking . 21
6.2 Electrical requirements . 21
6.2.1 Protection against direct contact . 21
6.2.2 Residual current I . 21
PE
6.2.3 Voltage protection level U . 21
p
6.2.4 Operating duty . 21
6.2.5 Disconnectors and status indicators . 22
6.2.6 Insulation resistance . 23
6.2.7 Dielectric withstand . 23
6.2.8 Continuous current I . 23
CPV
6.2.9 Total discharge current I (for multipole SPDs) . 23
Total
6.3 Mechanical requirements . 23
6.3.1 Mounting . 23
6.3.2 Screws, current carrying parts and connections . 23

IEC 61643-31:2018 © IEC 2018 – 3 –
6.3.3 External connections . 23
6.3.4 Air clearances and creepage distances . 24
6.3.5 Mechanical strength. 24
6.4 Environmental and material requirements . 24
6.4.1 General . 24
6.4.2 Life test under damp heat . 24
6.4.3 Electromagnetic compatibility . 24
6.5 Additional requirements for specific SPD designs . 25
6.5.1 One-port SPDs with separate input/output terminals – Rated load
current I . 25
L
6.5.2 Environmental tests for outdoor SPDs . 25
6.5.3 SPDs with separate isolated circuits . 25
6.6 Additional parameter if declared by the manufacturer – Maximum discharge
current I . 25
max
7 Type tests . 25
7.1 General . 25
7.2 Testing procedures . 26
7.2.1 General . 26
7.2.2 Test impulses . 30
7.2.3 Characteristics of power sources for testing . 30
7.3 Indelibility of markings . 32
7.4 Electrical tests . 32
7.4.1 Residual current I . 32
PE
7.4.2 Operating duty test . 33
7.4.3 Disconnectors and safety performance of overstressed SPDs . 37
7.4.4 SPD failure mode behaviour test . 38
7.4.5 Dielectric withstand . 41
7.4.6 Continuous current I . 42
CPV
7.5 Mechanical tests . 42
7.5.1 Verification of air clearances and creepage distances . 42
7.5.2 Pass criteria . 42
7.6 Environmental and material tests . 45
7.6.1 Life test under damp heat . 45
7.6.2 Pass criteria . 45
7.7 Additional tests for specific SPD designs . 46
7.7.1 Test for one-port SPDs with separate input/output terminals . 46
7.7.2 Environmental tests for outdoor SPDs . 46
7.7.3 SPDs with separate isolated circuits . 46
8 Routine and acceptance tests . 46
8.1 Routine tests. 46
8.2 Acceptance tests . 47
Annex A (normative) Tests to determine the presence of a voltage-switching
component and the magnitude of the follow current of an SPD . 48
A.1 General . 48
A.2 Test to determine the presence of a voltage-switching component . 48
A.3 Test to determine the magnitude of the follow current . 48
Annex B (informative) Transient behaviour of the PV test source . 49
B.1 Transient behaviour of the PV test source according to 7.2.3.1 . 49

– 4 – IEC 61643-31:2018 © IEC 2018
B.2 Test setup using a semiconductor switch to determine the transient
behaviour of a PV test source . 49
B.3 Alternative test setup using a fuse . 50
Bibliography . 53

Figure 1 – I/U characteristics . 31
Figure 2 – Flow chart of the operating duty test . 33
Figure 3 – Example of test setup for operating duty test . 34
Figure 4 – Operating duty test timing diagram for test classes I and II . 35
Figure 5 – Additional duty test timing diagram for test class I . 36
Figure 6 – Operating duty test timing diagram for test class III . 36
Figure 7 – Example of sample preparation for SPD failure mode behaviour test . 39
Figure B.1 – Test setup using an adjustable semiconductor switch to determine the
transient behaviour of a PV test source . 49
Figure B.2 – Time behaviour of voltage and current during disconnection operating
time of a semiconductor switch at a PV-source I = 4 A, open-circuit voltage = 640 V . 49
SC
Figure B.3 – Semiconductor disconnection behaviour (normalized) with intersection
point i(t) / u(t) . 50
Figure B.4 – I/U-characteristic of the PV test source calculated from the normalized
current and voltage records in Figure B.3 . 50
Figure B.5 – Test setup using a fuse to determine the transient behaviour of a PV test
source . 51
Figure B.6 – Normalized disconnection behaviour during operation of a fuse rated
0,1 x I at a PV test source with intersection point i(t) and u(t) . 51
SCPV
Figure B.7 – I/U-characteristic of the PV test source calculated from the normalized
current and voltage records in Figure B.6 . 52

Table 1 – List of acronyms and symbols . 17
Table 2 – Compliant termination and connection methods . 24
Table 3 – Environmental and material requirements . 24
Table 4 – Type test requirements for SPDs . 28
Table 5 – Common pass criteria for type tests . 29
Table 6 – Specific power source characteristics for operating duty tests . 31
Table 7 – Specific power source characteristics for failure mode tests . 32
Table 8 – Dielectric withstand . 41
Table 9 – Air clearances for SPDs . 43
Table 10 – Creepage distances for SPDs . 44
Table 11 – Relationship between material groups and classifications . 45
Table 12 – Test conductors for rated load current test . 46

IEC 61643-31:2018 © IEC 2018 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
LOW-VOLTAGE SURGE PROTECTIVE DEVICES –

Part 31: Requirements and test methods
for SPDs for photovoltaic installations

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
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agreement between the two organizations.
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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
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International Standard IEC 61643-31 has been prepared by subcommittee 37A: Low-voltage
surge protective devices, of IEC technical committee 37: Surge arresters.
The text of this standard is based on the following documents:
FDIS Report on voting
37A/306/FDIS 37A/310/RVD
Full information on the voting for the approval of this standard can be found in the report on
voting indicated in the above table.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

– 6 – IEC 61643-31:2018 © IEC 2018
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 publication will remain unchanged until
the stability date indicated on the IEC website under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct
understanding of its contents. Users should therefore print this document using a
colour printer.
IEC 61643-31:2018 © IEC 2018 – 7 –
INTRODUCTION
This part of IEC 61643 addresses safety and performance tests for surge protective devices
(SPDs) to be installed on the DC side of photovoltaic installations to protect against induced
and direct lightning effects.
There are three classes of tests:
1) The Class I test is intended to simulate partial conducted lightning current impulses. SPDs
subjected to Class I test methods are generally recommended for locations at points of
high exposure, e.g., line entrances to buildings protected by lightning protection systems.
2) SPDs tested to Class II or Class III test methods are subjected to impulses of shorter
duration.
3) SPDs are tested on a “black box” basis as far as possible.
Tests take into account that photovoltaic generators:
• behave like current generators,
• that their output current depends on the incident light intensity and temperature,
• that their short-circuit current is slightly higher than the operating output current,
• are connected in series and/or parallel combinations leading to a great variety of voltages,
currents and powers from a few hundreds of W (in residential installations) to several MW
(photovoltaic fields).
The specific electrical parameters of PV installations on the DC side require specific test
requirements for SPDs.
IEC 61643-32 addresses the selection and application principles of SPDs in practical
situations for PV application (work in progress).

– 8 – IEC 61643-31:2018 © IEC 2018
LOW-VOLTAGE SURGE PROTECTIVE DEVICES –

Part 31: Requirements and test methods
for SPDs for photovoltaic installations

1 Scope
This part of IEC 61643 is applicable to Surge Protective Devices (SPDs), intended for surge
protection against indirect and direct effects of lightning or other transient overvoltages.
These devices are designed to be connected to the DC side of photovoltaic installations rated
up to 1 500 V DC.
These devices contain at least one non-linear component and are intended to limit surge
voltages and divert surge currents. Performance characteristics, safety requirements,
standard methods for testing and ratings are established.
SPDs complying with this standard are exclusively dedicated to be installed on the DC side of
photovoltaic generators and the DC side of inverters.
SPDs for PV systems with energy storage (e.g. batteries, capacitor banks) are not covered.
SPDs with separate input and output terminals that contain specific series impedance
between these terminal(s) (so called two-port SPDs according to IEC 61643-11:2011) are not
covered.
SPDs compliant with this standard are designed to be permanently connected where
connection and disconnection of fixed SPDs can only be done using a tool. This standard
does not apply to portable SPDs
NOTE 1 In general SPDs for PV applications do not contain a specific series impedance between the input/output
terminals due to power efficiency considerations.
NOTE 2 Wherever reference is made to the e
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