IEC 62790:2020
(Main)Junction boxes for photovoltaic modules - Safety requirements and tests
Junction boxes for photovoltaic modules - Safety requirements and tests
IEC 62790:2020 describes safety requirements, constructional requirements and tests for junction boxes up to 1 500 V DC for use on photovoltaic modules in accordance with class II of IEC 61140:2016.
This document applies also to enclosures mounted on PV-modules containing electronic circuits for converting, controlling, monitoring or similar operations. Additional requirements concerning the relevant operations are applied under consideration of the environmental conditions of the PV-modules. This document does not apply to the electronic circuits of these devices, for which other IEC standards apply. This second edition cancels and replaces the first edition published in 2014. This edition includes the following significant technical changes with respect to the previous edition:
- Modifications in normative references and terms and definitions;
- Improvement of declaration of categories for junction boxes in 4.1;
- Clarification for ambient temperature in 4.1;
- Addition of requirement to provide information concerning RTE/RTI or TI in 4.2;
- Reference to IEC 62930 instead of EN 50618 in 4.6;
- Addition of "Functional insulation" in Table 1;
- Addition of "Distance through cemented joints" in Table 3;
- Correction of procedure of process to categorize material groups (deletion of PTI) in 4.15.2.3;
- Requirement for approval of RTE/RTI or TI for insulation parts in 4.16.1 and 4.16.2;
- Change of requirements concerning electrochemical potential in 4.17.2;
- Clarification for IP-test in 5.3.4.2;
- Addition of test voltage for cemented joints in 5.3.6 and 5.3.16;
- Addition of detailled description on how to prepare the test sample for the thermal cycle test in 5.3.9.1;
- New test procedure for bypass diode thermal test (5.3.18) in accordance with MQT 18.1 of IEC 61215-2:2016;
- New test procedure for reverse overload current test in 5.3.23;
- New Figure 1 for thermal cycle test.
Boîtes de jonction pour modules photovoltaïques - Exigences de sécurité et essais
L’IEC 62790:2020 décrit les exigences de sécurité, les exigences de construction et les essais relatifs aux boîtes de jonction jusqu’à 1 500 V en courant continu utilisées sur des modules photovoltaïques conformes à la classe II de l’IEC 61140:2016. Le présent document s’applique également aux enveloppes montées sur des modules photovoltaïques comportant des circuits électroniques pour la conversion, le contrôle, la surveillance ou opérations similaires. Des exigences supplémentaires concernant les opérations correspondantes sont appliquées en considérant les conditions d’environnement des modules photovoltaïques. Le présent document ne s’applique pas aux circuits électroniques de ces dispositifs pour lesquels d’autres normes IEC s’appliquent. Cette deuxième édition annule et remplace la première édition parue en 2014. Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente:
- Modifications des références normatives et des termes et définitions;
- Amélioration de la catégorisation des boîtes de jonction en 4.1;
- Clarification de la température ambiante en 4.1;
- Ajout de l'exigence prévoyant de fournir les indices RTE/RTI ou IT en 4.2;
- Référence à l’IEC 62930 à la place de la référence à l’EN 50618 en 4.6;
- Ajout de "l'isolation fonctionnelle" dans le Tableau 1;
- Ajout de "ligne de fuite entre les bords du joint scellé" dans le Tableau 3;
- Correction de la procédure du processus de catégorisation des groupes de matériaux (suppression de l’ITC) au 4.15.2.3;
- Exigence d'approbation des indices RTE/RTI ou IT pour les parties isolantes en 4.16.1 et 4.16.2;
- Modification des exigences concernant le potentiel électrochimique en 4.17.2;
- Clarification des essais de vérification du code IP au 5.3.4.2;
- Ajout de la tension d'essai pour les joints scellés en 5.3.6 et 5.3.16;
- Ajout de la description détaillée sur la façon de préparer les éprouvettes pour l'essai de cycle thermique en 5.3.9.1;
- Nouvelle procédure d'essai pour l'essai thermique la diode de dérivation (5.3.18) conformément au MQT 18.1 de l’IEC 61215-2: 2016;
- Nouvelle procédure d'essai pour l'essai de courant de surcharge inverse au 5.3.23;
- Nouvelle Figure 1 pour l'essai de cycle thermique.
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IEC 62790 ®
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STANDARD
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Junction boxes for photovoltaic modules – Safety requirements and tests
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IEC 62790 ®
Edition 2.0 2020-07
REDLINE VERSION
INTERNATIONAL
STANDARD
colour
inside
Junction boxes for photovoltaic modules – Safety requirements and tests
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 27.160 ISBN 978-2-8322-8680-7
– 2 – IEC 62790:2020 RLV © IEC 2020
CONTENTS
FOREWORD . 5
1 Scope . 8
2 Normative references . 8
3 Terms and definitions . 11
4 Constructional requirements and performance . 15
4.1 General . 15
4.2 Marking and identification . 16
4.2.1 Identification . 16
4.2.2 Marking . 16
4.2.3 Technical documentation . 16
4.3 Protection against electric shock . 17
4.4 Terminations, connecting devices and connection methods . 17
4.5 Connectors . 18
4.6 Cables . 18
4.7 Resistance to ageing . 18
4.8 General design . 18
4.9 Degree of protection (IP) . 19
4.10 Dielectric strength . 19
4.11 Range of ambient temperature . 19
4.12 Cable anchorage . 19
4.13 Mechanical strength . 19
4.14 Insulation . 20
4.14.1 Type of insulation . 20
4.14.2 Basic insulation . 20
4.14.3 Supplementary insulation . 20
4.14.4 Double insulation . 20
4.14.5 Reinforced insulation . 20
4.15 Clearances and creepage distances . 20
4.15.1 Clearances . 20
4.15.2 Creepage distances . 21
4.16 Insulation parts . 23
4.16.1 Outer accessible parts . 23
4.16.2 Inner parts keeping active parts in position . 23
4.17 Current carrying parts and resistance against corrosion . 24
4.18 Sealing . 24
4.19 Bypass-diode . 24
4.20 Knock-out inlets (outlets) intended to be removed by mechanical impact . 24
5 Tests . 24
5.1 General . 24
5.2 Preparation of specimens . 26
5.3 Performance of tests . 27
5.3.1 General . 27
5.3.2 Durability of marking . 27
5.3.3 Fixing of lid on rewirable junction box . 27
5.3.4 Protection against electric shock . 28
5.3.5 Measurement of clearances and creepage distances . 28
5.3.6 Dielectric strength . 28
5.3.7 Resistance to corrosion . 28
5.3.8 Mechanical strength at lower temperatures . 29
5.3.9 Thermal cycle test (IEC 60068-2-14:2009, Test Nb) . 29
5.3.10 Damp heat test . 30
5.3.11 Weather resistance test . 30
5.3.12 Flammability class . 30
5.3.13 Ball pressure test . 31
5.3.14 Glow wire test . 31
5.3.15 Resistance against ageing . 31
5.3.16 Wet leakage current test . 31
5.3.17 Humidity freeze test . 32
5.3.18 Bypass diode thermal test . 33
5.3.19 Test of terminations and connection methods . 34
5.3.20 Knock-out inlets (outlets) intended to be removed by mechanical impact . 34
5.3.21 Test of cord anchorage . 35
5.3.22 Retention on the mounting surface . 37
5.3.23 Reverse current test at junction box . 37
5.4 Test schedule . 38
Annex A (informative) Symbol "Do not disconnect under load" . 50
Annex B (normative) Qualification of conformal coatings for protection against
pollution . 51
B.1 General . 51
B.2 Technical properties . 51
B.3 Qualification of coatings . 51
Annex C (normative) Measurement of clearances and creepage distances . 54
Bibliography . 58
Figure 1 – Thermal cycling test – Temperature and applied current profile . 45
Figure 2 – Humidity-freeze cycle . 45
Figure 3 – Typical arrangement for the cable anchorage pull test . 46
Figure 4 – Typical arrangement for torsion test . 46
Figure 5 – Typical arrangement for flammability test in accordance with 5.3.12.2 . 47
Figure 6 – Measurement of voltage drop . 47
Figure 7 – Bypass diode thermal test . 48
Figure 8 – Proper attachment of 5 N weight to junction box. 49
Figure A.1 – Symbol "DO NOT DISCONNECT UNDER LOAD" . 50
Figure A.2 – Symbol "DO NOT DISCONNECT UNDER LOAD" (IEC 60417-6070:2011-06) . 50
Figure C.1 – Examples of methods of measuring clearances and creepage distances . 57
Table 1 – Required type of insulation . 20
Table 2 – Rated impulse voltages and minimum clearances . 21
Table 3 – Creepage distances for basic insulation . 22
Table 4 – Number of specimens . 25
Table 5 – Values of torque for screw-type clamping units . 26
Table 6 – Pull forces for cord anchorage . 36
– 4 – IEC 62790:2020 RLV © IEC 2020
Table 7 – Values for torsion test . 36
Table 8 – Marking, information, documentation, test group A . 38
Table 9 – Material test, test group B (single tests) . 39
Table 10 – Constructional requirements, test group C (single tests) . 40
Table 11 – Mechanical tests, test group D (single tests) . 40
Table 12 – Test sequence I, test group E (tests to be performed consecutively in this
order). 41
Table 13 – Test sequence II, test group F (tests to be performed consecutively in this
order). 42
Table 14 – Test sequence III, test group G (tests to be performed consecutively in this
order). 43
Table 15 – Test sequence IV, test group H (tests to be performed consecutively in this
order). 44
Table 16 – Reverse current test, test group I . 44
Table 17 – Test sequence V, test group J (tests to be performed consecutively in this
order). 44
Table B.1 – Test parameters, test conditions and test procedures. 52
Table B.2 – Test sequence and conformity check (tests to be performed consecutively
in this order) . 53
Table C.1 – Dimensions of X . 54
INTERNATIONAL ELECTROTECHNICAL COMMISSION
_____________
JUNCTION BOXES FOR PHOTOVOLTAIC MODULES –
SAFETY REQUIREMENTS AND TESTS
FOREWORD
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– 6 – IEC 62790:2020 RLV © IEC 2020
International Standard IEC 62790 has been prepared by IEC technical committee 82: Solar
photovoltaic energy systems.
This second edition cancels and replaces the first edition published in 2014. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) Modifications in normative references and terms and definitions;
b) Improvement of declaration of categories for junction boxes in 4.1;
c) Clarification for ambient temperature in 4.1;
d) Addition of requirement to provide information concerning RTE/RTI or TI in 4.2;
e) Reference to IEC 62930 instead of EN 50618 in 4.6;
f) Addition of "Functional insulation" in Table 1;
g) Addition of "Distance through cemented joints" in Table 3;
h) Correction of procedure of process to categorize material groups (deletion of PTI) in
4.15.2.3;
i) Requirement for approval of RTE/RTI or TI for insulation parts in 4.16.1 and 4.16.2;
j) Change of requirements concerning electrochemical potential in 4.17.2;
k) Clarification for IP-test in 5.3.4.2;
l) Addition of test voltage for cemented joints in 5.3.6 and 5.3.16;
m) Addition of detailed description on how to prepare the test sample for the thermal cycle
test in 5.3.9.1;
n) New test procedure for bypass diode thermal test (5.3.18) in accordance with MQT 18.1 of
IEC 61215-2:2016;
o) New test procedure for reverse overload current test in 5.3.23;
p) New Figure 1 for thermal cycle test.
The text of this International Standard is based on the following documents:
FDIS Report on voting
82/1719/FDIS 82/1738/RVD
Full information on the voting for the approval of this International Standard can be found in
the report on voting indicated in the above table.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data related
to the specific document. At this date, the document 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
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– 8 – IEC 62790:2020 RLV © IEC 2020
JUNCTION BOXES FOR PHOTOVOLTAIC MODULES –
SAFETY REQUIREMENTS AND TESTS
1 Scope
This document describes safety requirements, constructional requirements and tests for
junction boxes up to 1 500 V DC for use on photovoltaic modules in accordance with class II
of IEC 61140:20012016.
This document applies also to enclosures mounted on PV-modules containing electronic
circuits for converting, controlling, monitoring or similar operations. Additional requirements
concerning the relevant operations are applied under consideration of the environmental
conditions of the PV-modules. This document does not apply to the electronic circuits of these
devices, for which other IEC standards apply.
NOTE For junction boxes in accordance with classes 0 and III of IEC 61140:20012016, in photovoltaic-systems,
this document can be used as a guideline.
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 60060-1, High-voltage test techniques – Part 1: General definitions and test requirements
IEC 60068-1, Environmental testing – Part 1: General and guidance
IEC 60068-2-14:2009, Environmental testing – Part 2-14: Tests – Test N: Change of
temperature
IEC 60068-2-70, Environmental testing – Part 2-70: Tests – Test Xb: Abrasion of markings
and letterings caused by rubbing of fingers and hands
IEC 60068-2-75, Environmental testing – Part 2-75: Tests – Test Eh: Hammer tests
IEC 60068-2-78, Environmental testing – Part 2-78: Tests – Test Cab: Damp heat, steady
state
IEC 60228, Conductors of insulated cables
IEC 60216-1, Electrical insulating materials – Thermal endurance properties – Part 1: Ageing
procedures and evaluation of test results
IEC 60216-5, Electrical insulating materials – Thermal endurance properties – Part 5:
Determination of relative thermal endurance index (RTE) of an insulating material
IEC 60352-2, Solderless connections – Part 2: Crimped connections – General requirements,
test methods and practical guidance
IEC 60512-12-1, Connectors for electronic equipment – Tests and measurements –
Part 12-1: Soldering tests – Test 12a: Solderability, wetting, solder bath method
IEC 60512-12-2, Connectors for electronic equipment – Tests and measurements –
Part 12-2: Soldering tests – Test 12b: Solderability, wetting, soldering iron method
IEC 60352-3, Solderless connections – Part 3: Solderless accessible insulation displacement
connections – General requirements, test methods and practical guidance
IEC 60352-4, Solderless connections – Part 4: Solderless non-accessible insulation
displacement connections – General requirements, test methods and practical guidance
IEC 60352-5, Solderless connections – Part 5: Press-in connections – General requirements,
test methods and practical guidance
IEC 60352-6, Solderless connections – Part 6: Insulation piercing connections – General
requirements, test methods and practical guidance
IEC 60352-7, Solderless connections – Part 7: Spring clamp connections – General
requirements, test methods and practical guidance
IEC 60529, Degrees of protection provided by enclosures (IP Code)
IEC 60664-1:2007, Insulation coordination for equipment within low-voltage systems –
Part 1: Principles, requirements and tests
IEC/TR 60664-2-1, Insulation coordination for equipment within low-voltage systems – Part 2-
1: Application guide – Explanation of the application of the IEC 60664 series, dimensioning
examples and dielectric testing
IEC 60664-3, Insulation coordination for equipment within low-voltage systems – Part 3: Use
of coating, potting or moulding for protection against pollution
IEC 60695-2-11, Fire hazard testing – Part 2-11: Glowing/hot-wire based test methods –
Glow-wire flammability test method for end-products (GWEPT)
IEC 60695-10-2, Fire hazard testing – Part 10-2: Abnormal heat – Ball pressure test method
IEC 60695-11-10, Fire hazard testing – Part 11-10: Test flames – 50 W horizontal and vertical
flame test methods
IEC 60695-11-20:1999, Fire hazard testing – Part 11-20: Test flames – 500 W flame test
method
IEC/TR 60943, Guidance concerning the permissible temperature rise for parts of electrical
equipment, in particular for terminals
IEC 60947-7-1, Low-voltage switchgear and controlgear – Part 7-1: Ancillary equipment –
Terminal blocks for copper conductors
IEC 60998-2-1, Connecting devices for low-voltage circuits for household and similar
purposes – Part 2-1: Particular requirements for connecting devices as separate entities with
screw-type clamping units
IEC 60998-2-2, Connecting devices for low-voltage circuits for household and similar
purposes – Part 2-2: Particular requirements for connecting devices as separate entities with
screwless-type clamping units
– 10 – IEC 62790:2020 RLV © IEC 2020
IEC 60998-2-3, Connecting devices for low-voltage circuits for household and similar
purposes – Part 2-3: Particular requirements for connecting devices as separate entities with
insulation-piercing clamping units
IEC 60999-1:20001999, 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 mm up
to 35 mm (included)
IEC 60999-2, Connecting devices – Electrical copper conductors – Safety requirements for
screw-type and screwless-type clamping units – Part 2: Particular requirements for clamping
2 2
units for conductors above 35 mm up to 300 mm (included)
IEC 61032, Protection of persons and equipment by enclosures – Probes for verification
IEC 61140:20012016, Protection against electric shock – Common aspects for installation and
equipment
IEC 61191-1, Printed board assemblies – Part 1: Generic specification – Requirements for
soldered electrical and electronic assemblies using surface mount and related assembly
technologies
IEC 61210, Connecting-devices – Flat, quick-connect terminations for electrical copper
conductors – Safety requirements
IEC 61215-1:2016, Terrestrial photovoltaic (PV) modules – Design qualification and type
approval – Part 1: Test requirements
IEC 61215-2:2016, Terrestrial photovoltaic (PV) modules – Design qualification and type
approval – Part 2: Test procedures
IEC 61730-1:2016, Photovoltaic (PV) module safety qualification – Part 1: Requirements for
construction
IEC 61730-2:2004, Photovoltaic (PV) module safety qualification – Part 2: Requirements for
testing
IEC 62852, Connectors for DC-application in photovoltaic systems – Safety requirements and
tests
IEC 62930, Electric cables for photovoltaic systems with a voltage rating of 1,5 kV DC
ISO 868:2003, Plastics and ebonite – Determination of indentation hardness by means of a
durometer (Shore hardness)
ISO 4892-2:2013, Plastics – Methods of exposure to laboratory light sources – Part 2: Xenon-
arc lamps
ISO 4892-3:2006, Plastics – Methods of exposure to laboratory light sources – Part 3:
Fluorescent UV lamps
EN 50618, Electric cables for photovoltaic systems
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC TS 61836 as well as
the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp
3.1
module junction box
combination of parts, such as boxes, covers, cover-plates, lids, box extensions, accessories,
etc., providing after assembly and installation at the photovoltaic-module in normal use, an
appropriate protection against external influences, and a defined protection against contact
with enclosed live parts from any accessible direction
3.1.1
junction box for re-opening
junction box that can be opened at any time
Note 1 to entry: It may contain rewirable and non-rewirable connections.
3.1.1.1
junction box for factory wiring
junction box which is attached and connected to the PV module under controlled conditions,
usually at the manufacturer’s location
3.1.1.2
junction box for field wiring
junction box containing wiring connections that are intended to be made in the field
3.1.2
junction box, not intended to be re-opened
junction box that cannot be opened after mounting in the end application
Note 1 to entry: It may contain rewirable and non-rewirable connections.
3.2
cable gland
device permitting the introduction of one or more electric cables into the junction box so as to
maintain the relevant type of protection
[SOURCE: IEC 60050-426:2008, 426-04-18, modified – "and/or fibre optics" has been deleted
and "an electrical apparatus" has been replaced by "the junction box".]
3.3
sealing
method for providing the ability of a component to resist the ingress of contaminants
[SOURCE: IEC 60050-581:2008, 581-23-16]
3.4
spout hub
open entry of a box permitting the insertion and containment of a conduit
– 12 – IEC 62790:2020 RLV © IEC 2020
3.4
cable anchorage
ability to limit the displacement of a fitted flexible cable against pull and push forces and
torques
3.5
connector for photovoltaic-systems
PV-connector
component suitable for use in PV systems that terminates conductors for the purpose of
providing connection to and disconnection from a suitable mating component
3.6
intended use
use of a junction box in accordance with the information for use provided by the manufacturer
[SOURCE: IEC 60050-903:2013, 903-01-13, modified – "product, process or service" has
been replaced by "junction box" and "supplier" has been replaced by "manufacturer".]
3.7
terminal
clamping unit
part(s) of the terminal necessary for the mechanical clamping and the electrical connection of
the conductor(s), including the parts that are necessary to ensure the correct contact pressure
3.8
clearance
shortest distance in air between two conductive parts
[SOURCE: IEC 60050-426:2008, 426-04-12, modified – The note was deleted.]
3.9
creepage distance
shortest distance along the surface of the insulating material between two conductive parts
[SOURCE: IEC 60050-151:2001, 151-15-50, modified – "a solid insulating material" has been
replaced by "the insulating material".]
3.10
overvoltage category
numeral defining a transient overvoltage condition
[SOURCE: IEC 60050-581:2008, 581-21-02]
3.11
pollution
any addition of foreign matter, solid, liquid, or gaseous that can result in a reduction of electric
strength or surface resistivity of the insulation
[SOURCE: IEC 60050-442:1998, 442-01-28, modified – Definition revised and note deleted.]
3.12
pollution degree
numeral characterising the expected pollution of the micro-environment
[SOURCE: IEC 60050-581:2008, 581-21-07]
3.13
rated voltage
value of voltage assigned by the manufacturer to the junction box and to which operation and
performance characteristics are referred
Note 1 to entry: Rated voltage is equivalent to the rated system voltage according to IEC 61730-1.
[SOURCE: IEC 60664-1:2007, 3.9, modified – "a component, device or equipment" has been
replaced by "the junction box" and the note has been replaced by Note 1 to entry.]
3.14
rated insulation voltage
RMS withstand voltage value assigned by the manufacturer to the junction box, characterising
the specified (long term) withstand capability of its insulation
Note 1 to entry: The rated insulation voltage is not necessarily equal to the rated voltage, which is primarily
related to functional performance.
[SOURCE: IEC 60664-1:2007, 3.9.1, modified – "equipment or to a part of it" has been
replaced by "junction box".]
3.15
rated impulse voltage
impulse withstand voltage value assigned by the manufacturer to the junction box,
characterising the specified withstand capability of its insulation against transient
overvoltages
[SOURCE: IEC 60664-1:2007, 3.9.2, modified – "equipment or to a part of it" has been
replaced by "junction box".]
3.16
impulse withstand voltage
highest peak value of impulse voltage of prescribed specified form and polarity that does not
cause breakdown of the insulation under specified conditions
Note 1 to entry: The impulse withstand voltage is equal to or higher than the rated impulse voltage.
[SOURCE: IEC 60664-1:2007, 3.8.1, modified – "prescribed" replaced with "specifed" and
Note 1 to entry has been added.]
3.17
RMS withstand voltage
power-frequency withstand voltage
highest RMS value of a voltage that does not cause breakdown of insulation under specified
conditions
[SOURCE: IEC 60664-1:2007, 3.8.2]
3.18
current
3.18.1
rated current
current value assigned by the manufacturer, which the junction box can carry continuously
(without interruption) and simultaneously through all its contacts and bypass-diodes, if
applicable, wired with the largest specified conductor, at the highest specified maximum
ambient temperature, without the upper limiting temperature being exceeded
– 14 – IEC 62790:2020 RLV © IEC 2020
3.18.2
reverse current
I
REV
current value assigned by the manufacturer, which the junction box can carry at the highest
specified maximum ambient temperature, without causing a hazardous situation
Note 1 to entry: The reverse current is comparable with the reverse test current of the photovoltaic module (see
IEC 61730-2).
3.19
functional insulation
insulation between conductive parts that is necessary only for the proper functioning of the
equipment
[SOURCE: IEC 60664-1:2007, 3.17.1]
3.20
basic insulation
insulation applied to live parts to provide basic protection against electric shock
Note 1 to entry: Basic insulation does not necessarily include insulation used exclusively for functional purposes
(see IEC 61140:2001, 3.10.1).
[SOURCE: IEC 60664-1:2007, 3.17.2, modified – " against electric shock " and Note 1 to entry
have been added.]
Note 1 to entry: This concept does not apply to insulation used exclusively for functional purposes.
[SOURCE: IEC 61140:2016, 3.10.1, modified – "insulation of hazardous-live-parts which
provides" has been replaced by "insulation applied to live parts to provide" and "against
electric shock" has been added.]
3.21
supplementary insulation
independent insulation applied in addition to basic insulation, in order to provide protection
against electric shock in the event of a failure of basic insulation
[SOURCE: IEC 60664-1:2007, 3.17.3, modified – "for fault protection" has been replaced by
"in order to provide protection against electric shock in the event of a failure of basic
insulation".]
3.22
double insulation
insulation comprising both basic insulation and supplementary insulation
[SOURCE: IEC 60664-1:2007, 3.17.4]
3.23
reinforced insulation
single insulation system applied to live parts, which provides a degree of protection against
electric shock equivalent to double insulation under the conditions specified in the relevant
IEC standard (IEC 61140:2001, 3.10.4)
Note 1 to entry: A single insulation system does not imply that the insulation must be a homogeneous piece. It
may comprise several layers that cannot be tested singly as basic or supplementary insulation. Reinforced
insulation may comprise several layers which cannot be tested singly as basic insulation or supplementary
insulation.
[SOURCE: IEC 60664-1:2007, 3.17.5, modified – "insulation of hazardous-live-parts" has
been replaced by "single insulation system applied to live parts" and "under the conditions
specified in the relevant IEC standard" and Note 1 to entry have been added".]
3.24
working voltage
highest RMS value of the DC voltage across any particular insulation which can occur inside
the junction box when it operates at rated voltage
[SOURCE: IEC 60664-1:2007, 3.5, modified – "a.c. or" has been removed and “when the
equipment is supplied at rated voltage" has been replaced by "which can occur inside the
junction box when it operates at rated voltage".]
3.25
comparitive tracking index
CTI
numerical value of the maximum voltage in volts which a material can withstand without
tracking and without a persistent flame occurring under specified test conditions
[SOURCE: IEC 60050-212:2010, 212-11-59]
3.26
accessible part
part which can be touched by means of standard test finger
[SOURCE: IEC 60050-442:1998, 442-01-15]
3.27
photovoltaic cable
electrical cable (cabling) specifically designed for the purpose of carrying electric current from
photovoltaic devices and enduring the environmental conditions commonly encountered in
photovoltaic arrays
[SOURCE: IEC TS 61836:2016, 3.2.21, modified – Deletion of the notes to entry.]
3.28
maximum ambient temperature
maximum temperature of the ambient assigned by the manufacturer, in which the junction box
is able to operate without the limiting temperatures of the materials (TI, RTE/RTI) being
exceeded
4 Constructional requirements and performance
4.1 General
Junction boxes in accordance with this document can be categorized as
– junction boxes, for re-opening;
– junction boxes, not intended to be re-opened.
Junction boxes for re-opening can be distinguished as
– junction boxes for factory wiring;
– junction boxes for field wiring.
For junction boxes in accordance with this document, no values have been specified for
electric rated voltage and current. These values shall be declared by the manufacturer.
Junction boxes shall be suitable for durable use outside in an ambient temperature area from
–40 °C to +85 °C or as declared by the manufacturer if lower than −40 °C or higher than
+85 °C.
– 16 – IEC 62790:2020 RLV © IEC 2020
Junction boxes shall be so designed and dimensioned that they can withstand the electrical,
mechanical, thermal and corrosive stresses occurring in their intended use and present no
danger to the user or the environment.
Compliance with these requirements is verified by specified tests of this document.
4.2 Marking and identification
4.2.1 Identification
Junction boxes shall be identified and characterized by the following:
a) manufacturer’s name, trademark or mark of origin;
b) type identification;
c) rated current;
d) rated voltages or rated insulation voltages;
e) rated impulse voltage, if specified;
f) maximum working voltage;
g) pollution degree;
h) degree of protection by enclosure in accordance with IEC 60529;
i) range of temperature; (lowest and upper ambient temperature), if different from this
standard −40°C to +85°C ;
j) type of terminals;
k) connectable conductors;
l) reference to this document, if applicable;
m) symbols "Do not disconnect under load", as given in Annex A, or an adequate warning
notice in the particular respective national language;
n) polarity of connector, if applicable;
o) type and number of bypass-diodes, if applicable;
p) reverse current (I );
REV
q) RTE/RTI or TI (mechanical and electrical) of all insulating materials used in the junction
box.
4.2.2 Marking
The marking shall be indelible and easily legible.
The minimum marking on the junction boxes shall be that of items a), b) and n) in 4.2.1.
If connection of the junction box is performed by connectors, the warning notice listed in m) of
4.2.1 shall be on a label or similar on or close to the connector.
If connection of the junction box is performed made by connectors or by a fixed cable that has
implemented a connector on its end, the warning notice listed in m) of 4.2.1 shall be on a
label or similar on or close to the connector. An instruction where to place the warning notice
shall be included in the technical documentation.
Markings a) and b) of 4.2.1 shall be found on the smallest unit of packaging.
4.2.3 Technical documentation
Identification items of 4.2.1 not marked on the junction box in accordance with 4.2.2 and the
following information shall be given in the technical documentation of the manufacturer:
a) information on termination regarding the cable and cell connection, if applicable;
b) information regarding the connector(-system), if applicable;
c) information regarding mounting (e.g. backsheet material of the module) and mounting
material (e.g. sealing material, adhesive), if applicable.
4.3 Protection against electric shock
4.3.1 A junction box shall be so designed that, after mounting, the live parts are not
accessible. This requirement shall be fulfilled even if there is any deformation of the housing
and/or cover as a result of mechanical and thermal stress, which can occur during normal
use; furthermore, the degree of protection of the housing may not be impaired by this possible
deformation.
4.3.2 Parts intended to be removed shall only be detachable with the aid of tools. Lids that
are attached without screws shall have one or several detectable facilities, for example
recesses, which e
...
IEC 62790 ®
Edition 2.0 2020-07
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Junction boxes for photovoltaic modules – Safety requirements and tests
Boîtes de jonction pour modules photovoltaïques – Exigences de sécurité
et essais
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IEC 62790 ®
Edition 2.0 2020-07
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Junction boxes for photovoltaic modules – Safety requirements and tests
Boîtes de jonction pour modules photovoltaïques – Exigences de sécurité
et essais
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 27.160 ISBN 978-2-8322-8488-9
– 2 – IEC 62790:2020 © IEC 2020
CONTENTS
FOREWORD . 5
1 Scope . 7
2 Normative references . 7
3 Terms and definitions . 9
4 Constructional requirements and performance . 13
4.1 General . 13
4.2 Marking and identification . 14
4.2.1 Identification . 14
4.2.2 Marking . 14
4.2.3 Technical documentation . 15
4.3 Protection against electric shock . 15
4.4 Terminations, connecting devices and connection methods . 15
4.5 Connectors . 16
4.6 Cables . 16
4.7 Resistance to ageing . 16
4.8 General design . 16
4.9 Degree of protection (IP) . 17
4.10 Dielectric strength . 17
4.11 Range of ambient temperature . 17
4.12 Cable anchorage . 17
4.13 Mechanical strength . 17
4.14 Insulation . 18
4.14.1 Type of insulation . 18
4.14.2 Basic insulation . 18
4.14.3 Supplementary insulation . 18
4.14.4 Double insulation . 18
4.14.5 Reinforced insulation . 18
4.15 Clearances and creepage distances . 19
4.15.1 Clearances . 19
4.15.2 Creepage distances . 19
4.16 Insulation parts . 21
4.16.1 Outer accessible parts . 21
4.16.2 Inner parts keeping active parts in position . 21
4.17 Current carrying parts and resistance against corrosion . 21
4.18 Sealing . 22
4.19 Bypass-diode . 22
4.20 Knock-out inlets (outlets) intended to be removed by mechanical impact . 22
5 Tests . 22
5.1 General . 22
5.2 Preparation of specimens . 23
5.3 Performance of tests . 25
5.3.1 General . 25
5.3.2 Durability of marking . 25
5.3.3 Fixing of lid on rewirable junction box . 25
5.3.4 Protection against electric shock . 25
5.3.5 Measurement of clearances and creepage distances . 26
5.3.6 Dielectric strength . 26
5.3.7 Resistance to corrosion . 26
5.3.8 Mechanical strength at lower temperatures . 26
5.3.9 Thermal cycle test (IEC 60068-2-14:2009, Test Nb) . 27
5.3.10 Damp heat test . 28
5.3.11 Weather resistance test . 28
5.3.12 Flammability class . 28
5.3.13 Ball pressure test . 29
5.3.14 Glow wire test . 29
5.3.15 Resistance against ageing . 29
5.3.16 Wet leakage current test . 29
5.3.17 Humidity freeze test . 30
5.3.18 Bypass diode thermal test . 30
5.3.19 Test of terminations and connection methods . 31
5.3.20 Knock-out inlets (outlets) intended to be removed by mechanical impact . 32
5.3.21 Test of cord anchorage . 32
5.3.22 Retention on the mounting surface . 34
5.3.23 Reverse current test at junction box . 34
5.4 Test schedule . 35
Annex A (informative) Symbol "Do not disconnect under load" . 45
Annex B (normative) Qualification of conformal coatings for protection against
pollution . 46
B.1 General . 46
B.2 Technical properties . 46
B.3 Qualification of coatings . 46
Annex C (normative) Measurement of clearances and creepage distances . 49
Bibliography . 53
Figure 1 – Thermal cycling test – Temperature and applied current profile . 40
Figure 2 – Humidity-freeze cycle . 41
Figure 3 – Typical arrangement for the cable anchorage pull test . 41
Figure 4 – Typical arrangement for torsion test . 42
Figure 5 – Typical arrangement for flammability test in accordance with 5.3.12.2 . 42
Figure 6 – Measurement of voltage drop . 43
Figure 7 – Bypass diode thermal test . 43
Figure 8 – Proper attachment of 5 N weight to junction box. 44
Figure A.1 – Symbol "DO NOT DISCONNECT UNDER LOAD" . 45
Figure A.2 – Symbol "DO NOT DISCONNECT UNDER LOAD" (IEC 60417-6070:2011-06) . 45
Figure C.1 – Examples of methods of measuring clearances and creepage distances . 52
Table 1 – Required type of insulation . 18
Table 2 – Rated impulse voltages and minimum clearances . 19
Table 3 – Creepage distances for basic insulation . 20
Table 4 – Number of specimens . 23
Table 5 – Values of torque for screw-type clamping units . 24
Table 6 – Pull forces for cord anchorage . 33
– 4 – IEC 62790:2020 © IEC 2020
Table 7 – Values for torsion test . 34
Table 8 – Marking, information, documentation, test group A . 35
Table 9 – Material test, test group B (single tests) . 36
Table 10 – Constructional requirements, test group C (single tests) . 37
Table 11 – Mechanical tests, test group D (single tests) . 37
Table 12 – Test sequence I, test group E (tests to be performed consecutively in this
order). 38
Table 13 – Test sequence II, test group F (tests to be performed consecutively in this
order). 38
Table 14 – Test sequence III, test group G (tests to be performed consecutively in this
order). 39
Table 15 – Test sequence IV, test group H (tests to be performed consecutively in this
order). 39
Table 16 – Reverse current test, test group I . 39
Table 17 – Test sequence V, test group J (tests to be performed consecutively in this
order). 40
Table B.1 – Test parameters, test conditions and test procedures. 47
Table B.2 – Test sequence and conformity check (tests to be performed consecutively
in this order) . 48
Table C.1 – Dimensions of X . 49
INTERNATIONAL ELECTROTECHNICAL COMMISSION
_____________
JUNCTION BOXES FOR PHOTOVOLTAIC MODULES –
SAFETY REQUIREMENTS AND TESTS
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,
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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
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3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
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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
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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
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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) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of
patent rights. IEC shall not be held responsible for identifying any or all such patent rights.
International Standard IEC 62790 has been prepared by IEC technical committee 82: Solar
photovoltaic energy systems.
This second edition cancels and replaces the first edition published in 2014. This edition
constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) Modifications in normative references and terms and definitions;
b) Improvement of declaration of categories for junction boxes in 4.1;
c) Clarification for ambient temperature in 4.1;
d) Addition of requirement to provide information concerning RTE/RTI or TI in 4.2;
e) Reference to IEC 62930 instead of EN 50618 in 4.6;
f) Addition of "Functional insulation" in Table 1;
– 6 – IEC 62790:2020 © IEC 2020
g) Addition of "Distance through cemented joints" in Table 3;
h) Correction of procedure of process to categorize material groups (deletion of PTI) in
4.15.2.3;
i) Requirement for approval of RTE/RTI or TI for insulation parts in 4.16.1 and 4.16.2;
j) Change of requirements concerning electrochemical potential in 4.17.2;
k) Clarification for IP-test in 5.3.4.2;
l) Addition of test voltage for cemented joints in 5.3.6 and 5.3.16;
m) Addition of detailed description on how to prepare the test sample for the thermal cycle
test in 5.3.9.1;
n) New test procedure for bypass diode thermal test (5.3.18) in accordance with MQT 18.1 of
IEC 61215-2:2016;
o) New test procedure for reverse overload current test in 5.3.23;
p) New Figure 1 for thermal cycle test.
The text of this International Standard is based on the following documents:
FDIS Report on voting
82/1719/FDIS 82/1738/RVD
Full information on the voting for the approval of this International Standard can be found in
the report on voting indicated in the above table.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data related
to the specific document. At this date, the document 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.
JUNCTION BOXES FOR PHOTOVOLTAIC MODULES –
SAFETY REQUIREMENTS AND TESTS
1 Scope
This document describes safety requirements, constructional requirements and tests for
junction boxes up to 1 500 V DC for use on photovoltaic modules in accordance with class II
of IEC 61140:2016.
This document applies also to enclosures mounted on PV-modules containing electronic
circuits for converting, controlling, monitoring or similar operations. Additional requirements
concerning the relevant operations are applied under consideration of the environmental
conditions of the PV-modules. This document does not apply to the electronic circuits of these
devices, for which other IEC standards apply.
NOTE For junction boxes in accordance with classes 0 and III of IEC 61140:2016, in photovoltaic-systems, this
document can be used as a guideline.
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 60060-1, High-voltage test techniques – Part 1: General definitions and test requirements
IEC 60068-1, Environmental testing – Part 1: General and guidance
IEC 60068-2-14:2009, Environmental testing – Part 2-14: Tests – Test N: Change of
temperature
IEC 60068-2-70, Environmental testing – Part 2-70: Tests – Test Xb: Abrasion of markings
and letterings caused by rubbing of fingers and hands
IEC 60068-2-75, Environmental testing – Part 2-75: Tests – Test Eh: Hammer tests
IEC 60068-2-78, Environmental testing – Part 2-78: Tests – Test Cab: Damp heat, steady
state
IEC 60216-1, Electrical insulating materials – Thermal endurance properties – Part 1: Ageing
procedures and evaluation of test results
IEC 60216-5, Electrical insulating materials – Thermal endurance properties – Part 5:
Determination of relative thermal endurance index (RTE) of an insulating material
IEC 60352-2, Solderless connections – Part 2: Crimped connections – General requirements,
test methods and practical guidance
IEC 60352-3, Solderless connections – Part 3: Solderless accessible insulation displacement
connections – General requirements, test methods and practical guidance
– 8 – IEC 62790:2020 © IEC 2020
IEC 60352-4, Solderless connections – Part 4: Solderless non-accessible insulation
displacement connections – General requirements, test methods and practical guidance
IEC 60352-5, Solderless connections – Part 5: Press-in connections – General requirements,
test methods and practical guidance
IEC 60352-6, Solderless connections – Part 6: Insulation piercing connections – General
requirements, test methods and practical guidance
IEC 60352-7, Solderless connections – Part 7: Spring clamp connections – General
requirements, test methods and practical guidance
IEC 60529, Degrees of protection provided by enclosures (IP Code)
IEC 60664-1:2007, Insulation coordination for equipment within low-voltage systems –
Part 1: Principles, requirements and tests
IEC 60695-2-11, Fire hazard testing – Part 2-11: Glowing/hot-wire based test methods –
Glow-wire flammability test method for end-products (GWEPT)
IEC 60695-10-2, Fire hazard testing – Part 10-2: Abnormal heat – Ball pressure test method
IEC 60695-11-10, Fire hazard testing – Part 11-10: Test flames – 50 W horizontal and vertical
flame test methods
IEC 60695-11-20, Fire hazard testing – Part 11-20: Test flames – 500 W flame test method
IEC 60947-7-1, Low-voltage switchgear and controlgear – Part 7-1: Ancillary equipment –
Terminal blocks for copper conductors
IEC 60998-2-3, Connecting devices for low-voltage circuits for household and similar
purposes – Part 2-3: Particular requirements for connecting devices as separate entities with
insulation-piercing clamping units
IEC 60999-1:1999, Connecting devices – Electrical copper conductors – Safety requirements
for screw-type and screwless-type clamping units – Part 1: General requirements and
2 2
particular requirements for clamping units for conductors from 0,2 mm up to 35 mm
(included)
IEC 60999-2, Connecting devices – Electrical copper conductors – Safety requirements for
screw-type and screwless-type clamping units – Part 2: Particular requirements for clamping
2 2
units for conductors above 35 mm up to 300 mm (included)
IEC 61032, Protection of persons and equipment by enclosures – Probes for verification
IEC 61140:2016, Protection against electric shock – Common aspects for installation and
equipment
IEC 61191-1, Printed board assemblies – Part 1: Generic specification – Requirements for
soldered electrical and electronic assemblies using surface mount and related assembly
technologies
IEC 61210, Connecting-devices – Flat, quick-connect terminations for electrical copper
conductors – Safety requirements
IEC 61215-1:2016, Terrestrial photovoltaic (PV) modules – Design qualification and type
approval – Part 1: Test requirements
IEC 61215-2:2016, Terrestrial photovoltaic (PV) modules – Design qualification and type
approval – Part 2: Test procedures
IEC 61730-1:2016, Photovoltaic (PV) module safety qualification – Part 1: Requirements for
construction
IEC 62852, Connectors for DC-application in photovoltaic systems – Safety requirements and
tests
IEC 62930, Electric cables for photovoltaic systems with a voltage rating of 1,5 kV DC
ISO 868:2003, Plastics and ebonite – Determination of indentation hardness by means of a
durometer (Shore hardness)
ISO 4892-2, Plastics – Methods of exposure to laboratory light sources – Part 2: Xenon-arc
lamps
ISO 4892-3, Plastics – Methods of exposure to laboratory light sources – Part 3: Fluorescent
UV lamps
3 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC TS 61836 as well as
the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
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3.1
module junction box
combination of parts, such as boxes, covers, cover-plates, lids, box extensions, accessories,
etc., providing after assembly and installation at the photovoltaic-module in normal use, an
appropriate protection against external influences, and a defined protection against contact
with enclosed live parts from any accessible direction
3.1.1
junction box for re-opening
junction box that can be opened at any time
Note 1 to entry: It may contain rewirable and non-rewirable connections.
3.1.1.1
junction box for factory wiring
junction box which is attached and connected to the PV module under controlled conditions,
usually at the manufacturer’s location
3.1.1.2
junction box for field wiring
junction box containing wiring connections that are intended to be made in the field
– 10 – IEC 62790:2020 © IEC 2020
3.1.2
junction box, not intended to be re-opened
junction box that cannot be opened after mounting in the end application
3.2
cable gland
device permitting the introduction of one or more electric cables into the junction box so as to
maintain the relevant type of protection
[SOURCE: IEC 60050-426:2008, 426-04-18, modified – "and/or fibre optics" has been deleted
and "an electrical apparatus" has been replaced by "the junction box".]
3.3
sealing
method for providing the ability of a component to resist the ingress of contaminants
[SOURCE: IEC 60050-581:2008, 581-23-16]
3.4
cable anchorage
ability to limit the displacement of a fitted flexible cable against pull and push forces and
torques
3.5
connector for photovoltaic-systems
PV-connector
component suitable for use in PV systems that terminates conductors for the purpose of
providing connection to and disconnection from a suitable mating component
3.6
intended use
use of a junction box in accordance with the information for use provided by the manufacturer
[SOURCE: IEC 60050-903:2013, 903-01-13, modified – "product, process or service" has
been replaced by "junction box" and "supplier" has been replaced by "manufacturer".]
3.7
clamping unit
part(s) of the terminal necessary for the mechanical clamping and the electrical connection of
the conductor(s), including the parts that are necessary to ensure the correct contact pressure
3.8
clearance
shortest distance in air between two conductive parts
[SOURCE: IEC 60050-426:2008, 426-04-12, modified – The note was deleted.]
3.9
creepage distance
shortest distance along the surface of the insulating material between two conductive parts
[SOURCE: IEC 60050-151:2001, 151-15-50, modified – "a solid insulating material" has been
replaced by "the insulating material".]
3.10
overvoltage category
numeral defining a transient overvoltage condition
[SOURCE: IEC 60050-581:2008, 581-21-02]
3.11
pollution
any addition of foreign matter, solid, liquid, or gaseous that can result in a reduction of electric
strength or surface resistivity of the insulation
[SOURCE: IEC 60050-442:1998, 442-01-28, modified – Definition revised and note deleted.]
3.12
pollution degree
numeral characterising the expected pollution of the micro-environment
[SOURCE: IEC 60050-581:2008, 581-21-07]
3.13
rated voltage
value of voltage assigned by the manufacturer to the junction box and to which operation and
performance characteristics are referred
Note 1 to entry: Rated voltage is equivalent to the rated system voltage according to IEC 61730-1.
[SOURCE: IEC 60664-1:2007, 3.9, modified – "a component, device or equipment" has been
replaced by "the junction box" and the note has been replaced by Note 1 to entry.]
3.14
rated insulation voltage
RMS withstand voltage value assigned by the manufacturer to the junction box, characterising
the specified (long term) withstand capability of its insulation
Note 1 to entry: The rated insulation voltage is not necessarily equal to the rated voltage, which is primarily
related to functional performance.
[SOURCE: IEC 60664-1:2007, 3.9.1, modified – "equipment or to a part of it" has been
replaced by "junction box".]
3.15
rated impulse voltage
impulse withstand voltage value assigned by the manufacturer to the junction box,
characterising the specified withstand capability of its insulation against transient
overvoltages
[SOURCE: IEC 60664-1:2007, 3.9.2, modified – "equipment or to a part of it" has been
replaced by "junction box".]
3.16
impulse withstand voltage
highest peak value of impulse voltage of specified form and polarity that does not cause
breakdown of the insulation under specified conditions
Note 1 to entry: The impulse withstand voltage is equal to or higher than the rated impulse voltage.
[SOURCE: IEC 60664-1:2007, 3.8.1, modified – "prescribed" replaced with "specifed" and
Note 1 to entry has been added.]
– 12 – IEC 62790:2020 © IEC 2020
3.17
RMS withstand voltage
power-frequency withstand voltage
highest RMS value of a voltage that does not cause breakdown of insulation under specified
conditions
[SOURCE: IEC 60664-1:2007, 3.8.2]
3.18
current
3.18.1
rated current
current value assigned by the manufacturer, which the junction box can carry continuously
(without interruption) and simultaneously through all its contacts and bypass-diodes, if
applicable, wired with the largest specified conductor, at the maximum ambient temperature,
without the upper limiting temperature being exceeded
3.18.2
reverse current
I
REV
current value assigned by the manufacturer, which the junction box can carry at the maximum
ambient temperature, without causing a hazardous situation
Note 1 to entry: The reverse current is comparable with the reverse test current of the photovoltaic module (see
IEC 61730-2).
3.19
functional insulation
insulation between conductive parts that is necessary only for the proper functioning of the
equipment
[SOURCE: IEC 60664-1:2007, 3.17.1]
3.20
basic insulation
insulation applied to live parts to provide basic protection against electric shock
Note 1 to entry: This concept does not apply to insulation used exclusively for functional purposes.
[SOURCE: IEC 61140:2016, 3.10.1, modified – "insulation of hazardous-live-parts which
provides" has been replaced by "insulation applied to live parts to provide" and "against
electric shock" has been added.]
3.21
supplementary insulation
independent insulation applied in addition to basic insulation, in order to provide protection
against electric shock in the event of a failure of basic insulation
[SOURCE: IEC 60664-1:2007, 3.17.3, modified – "for fault protection" has been replaced by
"in order to provide protection against electric shock in the event of a failure of basic
insulation".]
3.22
double insulation
insulation comprising both basic insulation and supplementary insulation
[SOURCE: IEC 60664-1:2007, 3.17.4]
3.23
reinforced insulation
single insulation system applied to live parts, which provides a degree of protection against
electric shock equivalent to double insulation
Note 1 to entry: Reinforced insulation may comprise several layers which cannot be tested singly as basic
insulation or supplementary insulation.
[SOURCE: IEC 60664-1:2007, 3.17.5, modified – "insulation of hazardous-live-parts" has
been replaced by "single insulation system applied to live parts".]
3.24
working voltage
highest RMS value of the DC voltage across any particular insulation which can occur inside
the junction box when it operates at rated voltage
[SOURCE: IEC 60664-1:2007, 3.5, modified – "a.c. or" has been removed and “when the
equipment is supplied at rated voltage" has been replaced by "inside the junction box when it
operates at rated voltage".]
3.25
comparitive tracking index
CTI
numerical value of the maximum voltage in volts which a material can withstand without
tracking and without a persistent flame occurring under specified test conditions
[SOURCE: IEC 60050-212:2010, 212-11-59]
3.26
accessible part
part which can be touched by means of standard test finger
[SOURCE: IEC 60050-442:1998, 442-01-15]
3.27
photovoltaic cable
electrical cable (cabling) specifically designed for the purpose of carrying electric current from
photovoltaic devices and enduring the environmental conditions commonly encountered in
photovoltaic arrays
[SOURCE: IEC TS 61836:2016, 3.2.21, modified – Deletion of the notes to entry.]
3.28
maximum ambient temperature
maximum temperature of the ambient assigned by the manufacturer, in which the junction box
is able to operate without the limiting temperatures of the materials (TI, RTE/RTI) being
exceeded
4 Constructional requirements and performance
4.1 General
Junction boxes in accordance with this document can be categorized as
– junction boxes, for re-opening;
– junction boxes, not intended to be re-opened.
Junction boxes for re-opening can be distinguished as
– 14 – IEC 62790:2020 © IEC 2020
– junction boxes for factory wiring;
– junction boxes for field wiring.
For junction boxes in accordance with this document, no values have been specified for
electric rated voltage and current. These values shall be declared by the manufacturer.
Junction boxes shall be suitable for durable use outside in an ambient temperature area from
–40 °C to +85 °C or as declared by the manufacturer if lower than −40 °C or higher than
+85 °C.
Junction boxes shall be so designed and dimensioned that they can withstand the electrical,
mechanical, thermal and corrosive stresses occurring in their intended use and present no
danger to the user or the environment.
Compliance with these requirements is verified by specified tests of this document.
4.2 Marking and identification
4.2.1 Identification
Junction boxes shall be identified and characterized by the following:
a) manufacturer’s name, trademark or mark of origin;
b) type identification;
c) rated current;
d) rated voltages or rated insulation voltages;
e) rated impulse voltage, if specified;
f) maximum working voltage;
g) pollution degree;
h) degree of protection by enclosure in accordance with IEC 60529;
i) range of temperature; (lowest and upper ambient temperature), if different from −40°C to
+85°C ;
j) type of terminals;
k) connectable conductors;
l) reference to this document, if applicable;
m) symbols "Do not disconnect under load", as given in Annex A, or an adequate warning
notice in the respective national language;
n) polarity of connector, if applicable;
o) type and number of bypass-diodes, if applicable;
p) reverse current (I );
REV
q) RTE/RTI or TI (mechanical and electrical) of all insulating materials used in the junction
box.
4.2.2 Marking
The marking shall be indelible and easily legible.
The minimum marking on the junction boxes shall be that of items a), b) and n) in 4.2.1.
If connection of the junction box is made by connectors or by a fixed cable that has
implemented a connector on its end, the warning notice listed in m) of 4.2.1 shall be on a
label or similar on or close to the connector. An instruction where to place the warning notice
shall be included in the technical documentation.
Markings a) and b) of 4.2.1 shall be found on the smallest unit of packaging.
4.2.3 Technical documentation
Identification items of 4.2.1 not marked on the junction box in accordance with 4.2.2 and the
following information shall be given in the technical documentation of the manufacturer:
a) information on termination regarding the cable and cell connection, if applicable;
b) information regarding the connector(-system), if applicable;
c) information regarding mounting (e.g. backsheet material of the module) and mounting
material (e.g. sealing material, adhesive), if applicable.
4.3 Protection against electric shock
4.3.1 A junction box shall be so designed that, after mounting, the live parts are not
accessible. This requirement shall be fulfilled even if there is any deformation of the housing
and/or cover as a result of mechanical and thermal stress, which can occur during normal
use; furthermore, the degree of protection of the housing may not be impaired by this possible
deformation.
4.3.2 Parts intended to be removed shall only be detachable with the aid of tools. Lids that
are attached without screws shall have one or several detectable facilities, for example
recesses, which enable tools to be deployed in order to remove them. If the lid is removed
correctly, the tool shall not come into contact with the active parts.
4.3.3 Parts of junction boxes for field wiring in accordance with 3.1.1.2 shall be prevented
to be lost or to become loose.
4.4 Terminations, connecting devices and connection methods
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