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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
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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).
...