EN 62790:2015

SLOVENSKI STANDARD
01-maj-2015
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Junction boxes for photovoltaic modules - Safety requirements and tests
Ta slovenski standard je istoveten z: EN 62790:2015
ICS:
27.160 6RQþQDHQHUJLMD Solar energy engineering
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD EN 62790
NORME EUROPÉENNE
EUROPÄISCHE NORM
March 2015
ICS 27.160
English Version
Junction boxes for photovoltaic modules - Safety requirements
and tests
(IEC 62790:2014)
Boîtes de jonction pour modules photovoltaïques - Anschlussdosen für Photovoltaik-Module -
Exigences de sécurité et essais Sicherheitsanforderungen und Prüfungen
(IEC 62790:2014) (IEC 62790:2014)
This European Standard was approved by CENELEC on 2014-12-11. 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, 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: Avenue Marnix 17, B-1000 Brussels
© 2015 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN 62790:2015 E
Foreword
The text of document 82/876/FDIS, future edition 1 of IEC 62790, prepared by IEC/TC 82 "Solar
photovoltaic energy systems" was submitted to the IEC-CENELEC parallel vote and approved by
CENELEC as EN 62790:2015.
The following dates are fixed:
(dop) 2015-09-13
• latest date by which the document has to be implemented at
national level by publication of an identical national
standard or by endorsement
(dow) 2017-12-11
• latest date by which the national standards conflicting with
the document have to be withdrawn

Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC [and/or CEN] shall not be held responsible for identifying any or all such
patent rights.
Endorsement notice
The text of the International Standard IEC 62790:2014 was approved by CENELEC as a European
Standard without any modification.
In the official version, for Bibliography, the following notes have to be added for the standards indicated:
IEC 60352-3 NOTE Harmonized as EN 60352-3.
IEC 60352-4 NOTE Harmonized as EN 60352-4.
IEC 60364-7-712 NOTE Harmonized as HD 60364-7-712.
IEC 60512-1 NOTE Harmonized as EN 60512-1.
IEC 60695-10-2 NOTE Harmonized as EN 60695-10-2.
IEC 61210 NOTE Harmonized as EN 61210.
IEC 61215 NOTE Harmonized as EN 61215.
IEC 61646 NOTE Harmonized as EN 61646.

- 3 - EN 62790:2015
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
NOTE 1 When 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
- - Electric cables for photovoltaic systems EN 50618 -
IEC 60060-1 -  High-voltage test techniques - EN 60060-1 -
Part 1: General definitions and test
requirements
IEC 60068-1 -  Environmental testing - EN 60068-1 -
Part 1: General and guidance
IEC 60068-2-14 2009 Environmental testing - EN 60068-2-14 2009
Part 2-14: Tests - Test N: Change of
temperature
IEC 60068-2-70 -  Environmental testing - EN 60068-2-70 -
Part 2: Tests - Test Xb: Abrasion of
markings and letterings caused by rubbing
of fingers and hands
IEC 60068-2-75 -  Environmental testing - EN 60068-2-75 -
Part 2-75: Tests - Test Eh: Hammer tests
IEC 60068-2-78 -  Environmental testing - EN 60068-2-78 -
Part 2-78: Tests - Test Cab: Damp heat,
steady state
IEC 60228 -  Conductors of insulated cables EN 60228 -
IEC 60352-2 -  Solderless connections - EN 60352-2 -
Part 2: Crimped connections - General
requirements, test methods and practical
guidance
IEC 60512-12-1 -  Connectors for electronic equipment - EN 60512-12-1 -
Tests and measurements -
Part 12-1: Soldering tests - Test 12a:
Solderability, wetting, solder bath method

Publication Year Title EN/HD Year
IEC 60512-12-2 -  Connectors for electronic equipment - EN 60512-12-2 -
Tests and measurements -
Part 12-2: Soldering tests - Test 12b:
Solderability, wetting, soldering iron
method
IEC 60529 -  Degrees of protection provided by EN 60529 -
enclosures (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/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 EN 60664-3 -
low-voltage systems -
Part 3: Use of coating, potting or moulding
for protection against pollution
IEC 60695-2-11 -  Fire hazard testing - EN 60695-2-11 -
Part 2-11: Glowing/hot-wire based test
methods - Glow-wire flammability test
method for end-products (GWEPT)
IEC 60695-11-10 -  Fire hazard testing - EN 60695-11-10 -
Part 11-10: Test flames - 50 W horizontal
and vertical flame test methods
IEC 60695-11-20 1999 Fire hazard testing - EN 60695-11-20 1999
Part 11-20: Test flames - 500 W flame test
methods
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 - EN 60947-7-1 -
Part 7-1: Ancillary equipment - Terminal
blocks for copper conductors
IEC 60998-2-1 -  Connecting devices for low-voltage circuits EN 60998-2-1 -
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 EN 60998-2-2 -
for household and similar purposes -
Part 2-2: Particular requirements for
connecting devices as separate entities
with screwless-type clamping units

- 5 - EN 62790:2015
Publication Year Title EN/HD Year
IEC 60999-1 1999 Connecting devices - Electrical copper EN 60999-1 2000
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 60999-2 -  Connecting devices - Electrical copper EN 60999-2 -
conductors - Safety requirements for
screw-type and screwless-type clamping
units -
Part 2: Particular requirements for
clamping units for conductors above
35 mm² up to 300 mm² (included)
IEC 61032 -  Protection of persons and equipment by EN 61032 -
enclosures - Probes for verification
IEC 61140 2001 Protection against electric shock - EN 61140 2002
Common aspects for installation and
equipment
IEC 61730-1 -  Photovoltaic (PV) module safety EN 61730-1 -
qualification -
Part 1: Requirements for construction
IEC 61730-2 (mod) 2004 Photovoltaic (PV) module safety EN 61730-2 2007
qualification -
Part 2: Requirements for testing
IEC 62852 -  Connectors for DC-application in EN 62852 -
photovoltaic systems - Safety requirements
and tests
ISO 868 2003 Plastics and ebonite - Determination of EN ISO 868 2003
indentation hardness by means of a
durometer (Shore hardness)
ISO 4892-2 2013 Plastics - Methods of exposure to EN ISO 4892-2 2013
laboratory light sources -
Part 2: Xenon-arc lamps
ISO 4892-3 2006 Plastics - Methods of exposure to EN ISO 4892-3 2006
laboratory light sources -
Part 3: Fluorescent UV lamps
IEC 62790 ®
Edition 1.0 2014-11
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
PRICE CODE
INTERNATIONALE
CODE PRIX XA
ICS 27.160 ISBN 978-2-8322-1899-0

– 2 – IEC 62790:2014 © IEC 2014
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 . 13
4.2.1 Identification . 13
4.2.2 Marking . 14
4.2.3 Technical documentation . 14
4.3 Protection against electric shock . 14
4.4 Terminations, connecting devices and connection methods . 14
4.5 Connectors . 15
4.6 Cable . 15
4.7 Resistance to aging . 15
4.8 General design . 16
4.9 Degree of protection (IP) . 16
4.10 Dielectric strength . 16
4.11 Range of ambient temperature . 16
4.12 Cable anchorage . 16
4.13 Mechanical strength . 17
4.14 Insulation . 17
4.14.1 Type of insulation . 17
4.14.2 Basic insulation . 17
4.14.3 Supplementary insulation . 17
4.14.4 Double insulation . 17
4.14.5 Reinforced insulation . 18
4.15 Clearances and creepage distances . 18
4.15.1 Clearances . 18
4.15.2 Creepage distances . 18
4.16 Insulation parts . 20
4.16.1 Outer accessible parts . 20
4.16.2 Inner parts keeping active parts in position . 20
4.17 Current carrying parts and resistance against corrosion . 20
4.18 Sealing . 20
4.19 Bypass-diode . 20
4.20 Knock-out inlets (outlets) intended to be removed by mechanical impact . 21
5 Tests . 21
5.1 General . 21
5.2 Preparation of specimens . 23
5.3 Performance of tests . 24
5.3.1 General . 24
5.3.2 Durability of marking . 24
5.3.3 Fixing of lid on rewirable junction box . 24
5.3.4 Protection against electric shock . 25
5.3.5 Measurement of clearances and creepage distances . 25

IEC 62790:2014 © IEC 2014 – 3 –
5.3.6 Dielectric strength . 25
5.3.7 Resistance to corrosion . 25
5.3.8 Mechanical strength at lower temperatures . 25
5.3.9 Thermal cycle test (IEC 60068-2-14:2009, Test Nb) . 26
5.3.10 Damp heat test . 26
5.3.11 Weather resistance test . 26
5.3.12 Flammability class . 27
5.3.13 Ball pressure test . 27
5.3.14 Glow wire test . 27
5.3.15 Resistance against ageing . 27
5.3.16 Wet leakage current test . 27
5.3.17 Humidity-freeze-test . 28
5.3.18 Bypass diode thermal test . 29
5.3.19 Test of terminations and connection methods . 30
5.3.20 Knock-out inlets (outlets) intended to be removed by mechanical impact . 30
5.3.21 Test of cord anchorage . 31
5.3.22 Retention on the mounting surface . 32
5.3.23 Reverse current test at junction box . 33
5.4 Test schedule . 33
Annex A (informative) Symbol "Do not disconnect under load" . 42
Annex B (normative) Qualification of conformal coatings for protection against
pollution . 43
B.1 General . 43
B.2 Technical properties . 43
B.3 Qualification of coatings . 43
Annex C (normative) Measurement of clearances and creepage distances . 46
Bibliography . 50

Figure 1 – Thermal cycling test . 38
Figure 2 – Humidity-freeze cycle . 39
Figure 3 – Typical arrangement for the cable anchorage pull test . 39
Figure 4 – Typical arrangement for torsion test . 40
Figure 5 – Typical arrangement for flammability test according to 5.3.12.2 . 40
Figure 6 – Measurement of voltage drop . 41
Figure A.1 – Symbol "DO NOT DISCONNECT UNDER LOAD" . 42
Figure A.2 – Symbol "DO NOT DISCONNECT UNDER LOAD" (IEC 60417-6070) . 42
Figure B.1 – Test sequence and conformity check . 45
Figure C.1 – Examples of methods of measuring clearances and creepage distances . 49

Table 1 – Required type of insulation . 17
Table 2 – Rated impulse voltages and minimum clearances . 18
Table 3 – Creepage distances for basic insulation . 19
Table 4 – Number of specimens . 22
Table 5 – Values of torque for screw-type clamping units . 23
Table 6 – Pull forces for cord anchorage . 32
Table 7 – Values for torsion test . 32

– 4 – IEC 62790:2014 © IEC 2014
Table 8 – Marking, information, documentation, test group A . 33
Table 9 – Material test, test group B (single tests) . 34
Table 10 – Constructional requirements, test group C (single tests) . 35
Table 11 – Mechanical tests, test group D (single tests) . 35
Table 12 – Test sequence I, test group E (tests to be performed consecutively in this
order). 36
Table 13 – Test sequence II, test group F (tests to be performed consecutively in this
order). 36
Table 14 – Test sequence III, test group G (tests to be performed consecutively in this
order). 37
Table 15 – Test sequence IV, test group H (tests to be performed consecutively in this
order). 37
Table 16 – Reverse current test, test group I . 37
Table 17 – Test sequence V, test group J (tests to be performed consecutively in this
order). 38
Table B.1 – Test parameters, test conditions and test procedures. 44
Table C.1 – Dimensions of X . 46

IEC 62790:2014 © IEC 2014 – 5 –
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,
Technical Reports, Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC
Publication(s)”). Their preparation is entrusted to technical committees; any IEC National Committee interested
in the subject dealt with may participate in this preparatory work. International, governmental and non-
governmental organizations liaising with the IEC also participate in this preparation. IEC collaborates closely
with the International Organization for Standardization (ISO) in accordance with conditions determined by
agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence
between any IEC Publication and the corresponding national or regional publication shall be clearly indicated in
the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) 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.
The European Standard EN 50548 (first edition, 2011), has served as a basis for the
elaboration of this standard.
The text of this standard is based on the following documents:
FDIS Report on voting
82/876/FDIS 82/902/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.

– 6 – IEC 62790:2014 © IEC 2014
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.
The committee has decided that the contents of this publication 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 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 62790:2014 © IEC 2014 – 7 –
JUNCTION BOXES FOR PHOTOVOLTAIC MODULES –
SAFETY REQUIREMENTS AND TESTS
1 Scope
This International Standard describes safety requirements, constructional requirements and
tests for junction boxes up to 1 500 V dc for use on photovoltaic modules according to class II
of IEC 61140:2001.
This standard 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 standard does not apply to the electronic circuits of these
devices, for which other IEC-standards apply.
NOTE For junction boxes according to classes 0 and III of IEC 61140:2001, in photovoltaic-systems, this standard
can be used as a guideline.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and
are indispensable for its application. 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: 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 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 60529, Degrees of protection provided by enclosures (IP Code)

– 8 – IEC 62790:2014 © IEC 2014
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
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
methods
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
IEC 60999-1:2000, 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 61140:2001, Protection against electric shock – Common aspects for installation and
equipment
IEC 61730-1, 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 photovoltaic systems – Safety requirements and tests

IEC 62790:2014 © IEC 2014 – 9 –
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 following terms and definitions apply.
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 manufacturer’s location
3.1.1.2
junction box for field wiring
junction box containing wiring connections that are intended to 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]

– 10 – IEC 62790:2014 © IEC 2014
3.4
spout hub
open entry of a box permitting the insertion and containment of a conduit
3.5
cable anchorage
ability to limit the displacement of a fitted flexible cable against pull and push forces and
torques
3.6
connector for photovoltaic-systems
component suitable for use in PV-systems that terminates conductors for the purpose of
providing connection to and disconnection from a suitable mating component
3.7
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".]
3.8
terminal
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
3.9
clearance
shortest distance in air between two conductive parts
[SOURCE: IEC 60050-426:2008, 426-04-12]
3.10
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" has been replaced by "the".]
3.11
overvoltage category
numeral defining a transient overvoltage condition
[SOURCE: IEC 60050-581:2008, 581-21-02]
3.12
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]
3.13
pollution degree
numeral characterising the expected pollution of the micro-environment
[SOURCE: IEC 60050-581:2008, 581-21-07]

IEC 62790:2014 © IEC 2014 – 11 –
3.14
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.]
3.15
rated insulation voltage
r.m.s. 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".]
3.16
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".]
3.17
impulse withstand voltage
highest peak value of impulse voltage of prescribed 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 – Note 1 to entry has been added.]
3.18
r.m.s. withstand voltage
power-frequency withstand voltage
highest r.m.s. value of a voltage that does not cause breakdown of insulation under specified
conditions
[SOURCE: IEC 60664-1:2007, 3.8.2]
3.19
Current
3.19.1
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 ambient
temperature, without the upper limiting temperature being exceeded

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3.19.2
reverse current
I
REV
current value assigned by the manufacturer, which the junction box can carry at the highest
specified 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).
3.20
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]
3.21
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.]
3.22
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”.]
3.23
double insulation
insulation comprising both basic insulation and supplementary insulation
[SOURCE: IEC 60664-1:2007, 3.17.4]
3.24
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.
[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.]
3.25
working voltage
highest r.m.s. value of the dc voltage across any particular insulation which can occur inside
the junction box when the it operates at rated voltage

IEC 62790:2014 © IEC 2014 – 13 –
[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".]
3.26
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]
3.27
accessible part
part which can be touched by means of standard test finger
[SOURCE: IEC 60050-442:1998, 442-01-15]
4 Constructional requirements and performance
4.1 General
For junction boxes according to this standard, 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.
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 International
Standard.
4.2 Marking and identification
4.2.1 Identification
Junction boxes shall be identified and characterised 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 according to IEC 60529;
i) range of temperature; (lowest and upper ambient temperature), if different from this
standard;
j) type of terminals;
k) connectable conductors;
l) reference to this standard, if applicable;

– 14 – IEC 62790:2014 © IEC 2014
m) symbols ”Do not disconnect under load“, as given in Annex A, or an adequate warning
notice in the particular national language;
n) polarity of connector, if applicable;
o) type and number of bypass-diodes, if applicable;
p) reverse current (I ).
REV
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 junction box is performed by connectors, the warning notice listed in m) of
4.2.1 shall be on a label or
...