Audio/video, information and communication technology equipment - Part 2: Explanatory information related to IEC 62368-1:2018

IEC TR 62368-2:2019 is available as IEC TR 62368-2:2019 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition.
IEC TR 62368-2:2019 provides explanatory information related to IEC 62368-1. Only those subclauses considered to need further background reference information or explanation of their content to benefit the reader are included. Therefore, not all numbered subclauses are cited. Unless otherwise noted, all references are to clauses, subclauses, annexes, figures or tables located in IEC 62368-1:2018. This third edition updates the second edition of IEC 62368-2 published in 2014 to take into account changes made to IEC 62368-1:2014 as identified in the Foreword of IEC 62368-1:2018. This Technical Report is informative only. In case of a conflict between IEC 62368-1 and IEC TR 62368-2, the requirements in IEC 62368-1 prevail over this Technical Report.
Key words: Audio/Video, Safeguards, Information, Communication

Équipements des technologies de l'audio/vidéo, de l'information et de la communication - Partie 2 : Précisions relatives à l'IEC 62368-1:2018

IEC TR 62368-2:2019 est disponible sous forme de IEC TR 62368-2:2019 RLV qui contient la Norme internationale et sa version Redline, illustrant les modifications du contenu technique depuis l'édition précédente.
L'IEC TR 62368-2:2019 fournit des explications au sujet de l'IEC 62368-1. Ne sont inclus que les paragraphes qui nécessitent des informations complémentaires ou des explications pouvant bénéficier au lecteur. Par conséquent, certains numéros de paragraphes ne sont pas cités. Sauf indication contraire, toutes les références à des articles, paragraphes, annexes, figures ou tableaux renvoient à l'IEC 62368-1:2018 Cette troisième édition actualise la deuxième édition de l'IEC 62368-2 publiée en 2014 et intègre les modifications faites dans l'IEC 62368-1:2014 telles qu'indiquées dans l'Avant-propos de l'IEC 62368-1:2018. Le présent Rapport technique est un document informatif. En cas de conflits entre l'IEC 62368-1 et l'IEC TR 62368-2, les exigences de l'IEC 62368-1 prévalent sur le présent Rapport technique.
Mots-clés: Audio/Vidéo, Protection, Information, Communication

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Publication Date
06-May-2019
Current Stage
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Completion Date
07-May-2019
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IEC TR 62368-2
Edition 3.0 2019-05
TECHNICAL
REPORT
RAPPORT
TECHNIQUE
colour
inside
Audio/video, information and communication technology equipment –
Part 2: Explanatory information related to IEC 62368-1:2018
Équipements des technologies de l'audio/vidéo, de l'information
et de la communication –
Partie 2: Précisions relatives à l'IEC 62368-1:2018
IEC TR 62368-2:2019-05(en-fr)
---------------------- Page: 1 ----------------------
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---------------------- Page: 2 ----------------------
IEC TR 62368-2
Edition 3.0 2019-05
TECHNICAL
REPORT
RAPPORT
TECHNIQUE
colour
inside
Audio/video, information and communication technology equipment –
Part 2: Explanatory information related to IEC 62368-1:2018
Équipements des technologies de l'audio/vidéo, de l'information
et de la communication –
Partie 2: Précisions relatives à l'IEC 62368-1:2018
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 33.160.01; 35.020 ISBN 978-2-8322-6716-5

Warning! Make sure that you obtained this publication from an authorized distributor.

Attention! Veuillez vous assurer que vous avez obtenu cette publication via un distributeur agréé.

® Registered trademark of the International Electrotechnical Commission
Marque déposée de la Commission Electrotechnique Internationale
---------------------- Page: 3 ----------------------
– 2 – IEC TR 62368-2:2019 © IEC 2019
CONTENTS

FOREWORD ........................................................................................................................... 6

INTRODUCTION ..................................................................................................................... 9

0 Principles of this product safety standard ....................................................................... 10

1 Scope ............................................................................................................................ 12

2 Normative references ..................................................................................................... 13

3 Terms, definitions and abbreviations .............................................................................. 13

4 General requirements .................................................................................................... 16

5 Electrically-caused injury ............................................................................................... 23

6 Electrically-caused fire ................................................................................................... 70

7 Injury caused by hazardous substances ....................................................................... 105

8 Mechanically-caused injury .......................................................................................... 109

9 Thermal burn injury ...................................................................................................... 117

10 Radiation ..................................................................................................................... 126

Annex A Examples of equipment within the scope of this standard ................................. 133

Annex B Normal operating condition tests, abnormal operating condition tests and

single fault condition tests ................................................................................ 133

Annex C UV Radiation .................................................................................................... 136

Annex D Test generators ................................................................................................ 136

Annex E Test conditions for equipment containing audio amplifiers ................................ 137

Annex F Equipment markings, instructions, and instructional safeguards ........................ 137

Annex G Components ..................................................................................................... 138

Annex H Criteria for telephone ringing signals ................................................................ 146

Annex J Insulated winding wires for use without interleaved insulation ........................... 148

Annex K Safety interlocks ............................................................................................... 148

Annex L Disconnect devices ........................................................................................... 148

Annex M Equipment containing batteries and their protection circuits .............................. 149

Annex O Measurement of creepage distances and clearances ........................................ 158

Annex P Safeguards against conductive objects ............................................................. 158

Annex Q Circuits intended for interconnection with building wiring .................................. 159

Annex R Limited short-circuit test ................................................................................... 160

Annex S Tests for resistance to heat and fire .................................................................. 160

Annex T Mechanical strength tests ................................................................................. 162

Annex U Mechanical strength of CRTs and protection against the effects of

implosion .......................................................................................................... 163

Annex V Determination of accessible parts ..................................................................... 163

Annex X Alternative method for determing clearances for insulation in circuits

connected to an AC mains not exceeding 420 V peak (300 V RMS) .................. 163

Annex Y Construction requirements for outdoor enclosures ............................................ 164

Annex A (informative) Background information related to the use of SPDs ......................... 167

Annex B (informative) Background information related to measurement of discharges

– Determining the R-C discharge time constant for X- and Y-capacitors .............................. 180

Annex C (informative) Background information related to resistance to candle flame

ignition ................................................................................................................................ 192

---------------------- Page: 4 ----------------------
IEC TR 62368-2:2019 © IEC 2019 – 3 –

Bibliography ........................................................................................................................ 193

Figure 1 – Risk reduction as given in ISO/IEC Guide 51........................................................ 11

Figure 2 – HBSE Process Chart ............................................................................................ 12

Figure 3 – Protective bonding conductor as part of a safeguard ............................................ 15

Figure 4 – Safeguards for protecting an ordinary person ....................................................... 19

Figure 5 – Safeguards for protecting an instructed person .................................................... 19

Figure 6 – Safeguards for protecting a skilled person ............................................................ 20

Figure 7 – Flow chart showing the intent of the glass requirements ....................................... 22

Figure 8 – Conventional time/current zones of effects of AC currents (15 Hz to 100 Hz)

on persons for a current path corresponding to left hand to feet (see IEC/TS 60479-

1:2005, Figure 20) ................................................................................................................ 25

Figure 9 – Conventional time/current zones of effects of DC currents on persons for a

longitudinal upward current path (see IEC/TS 60479-1:2005, Figure 22) ............................... 26

Figure 10 – Illustration that limits depend on both voltage and current .................................. 27

Figure 11 – Illustration of working voltage ............................................................................. 39

Figure 12 – Illustration of transient voltages on paired conductor external circuits ................ 41

Figure 13 – Illustration of transient voltages on coaxial-cable external circuits ...................... 42

Figure 14 – Basic and reinforced insulation in Table 14 of IEC 62368-1:2018; ratio

reinforced to basic ................................................................................................................ 43

Figure 15 – Reinforced clearances according to Rule 1, Rule 2, and Table 14 ...................... 45

Figure 16 – Example illustrating accessible internal wiring .................................................... 53

Figure 17 – Waveform on insulation without surge suppressors and no breakdown ............... 56

Figure 18 – Waveforms on insulation during breakdown without surge suppressors .............. 57

Figure 19 – Waveforms on insulation with surge suppressors in operation ............................ 57

Figure 20 – Waveform on short-circuited surge suppressor and insulation ............................ 57

Figure 21 – Example for an ES2 source ................................................................................ 59

Figure 22 – Example for an ES3 source ................................................................................ 59

Figure 23 – Overview of protective conductors ...................................................................... 61

Figure 24 – Example of a typical touch current measuring network ....................................... 64

Figure 25 – Touch current from a floating circuit ................................................................... 66

Figure 26 – Touch current from an earthed circuit ................................................................. 67

Figure 27 – Summation of touch currents in a PABX ............................................................. 67

Figure 28 – Possible safeguards against electrically-caused fire ........................................... 75

Figure 29 – Fire clause flow chart ......................................................................................... 78

Figure 30 – Prevent ignition flow chart .................................................................................. 83

Figure 31 – Control fire spread summary .............................................................................. 85

Figure 32 – Control fire spread PS2 ...................................................................................... 86

Figure 33 – Control fire spread PS3 ...................................................................................... 87

Figure 34 – Fire cone application to a large component ........................................................ 96

Figure 35 – Flowchart demonstrating the hierarchy of hazard management ........................ 108

Figure 36 – Model for chemical injury .................................................................................. 109

Figure 37 – Direction of forces to be applied ....................................................................... 114

Figure 38 – Model for a burn injury ..................................................................................... 117

---------------------- Page: 5 ----------------------
– 4 – IEC TR 62368-2:2019 © IEC 2019

Figure 39 – Model for safeguards against thermal burn injury ............................................. 119

Figure 40 – Model for absence of a thermal hazard ............................................................. 120

Figure 41 – Model for presence of a thermal hazard with a physical safeguard in place ...... 120

Figure 42 – Model for presence of a thermal hazard with behavioural safeguard

in place ............................................................................................................................... 120

Figure 43 – Flowchart for evaluation of Image projectors (beamers) ................................... 128

Figure 44 – Graphical representation of L ,T .................................................................. 130

Aeq

Figure 45 – Overview of operating modes ........................................................................... 135

Figure 46 – Voltage-current characteristics (Typical data) ................................................... 140

Figure 47 – Example of IC current limiter circuit .................................................................. 144

Figure 48 – Current limit curves .......................................................................................... 147

Figure 49 – Example of a dummy battery circuit .................................................................. 157

Figure 50 – Example of a circuit with two power sources..................................................... 160

Figure A.1 – Installation has poor earthing and bonding; equipment damaged

(from ITU-T K.66) ................................................................................................................ 168

Figure A.2 – Installation has poor earthing and bonding; using main earth bar for

protection against lightning strike (from ITU-T K.66) ........................................................... 168

Figure A.3 – Installation with poor earthing and bonding, using a varistor and a GDT

for protection against a lightning strike ................................................................................ 169

Figure A.4 – Installation with poor earthing and bonding; equipment damaged (TV set) ...... 169

Figure A.5 – Safeguards ..................................................................................................... 170

Figure A.6 – Discharge stages ............................................................................................ 174

Figure A.7 – Holdover ......................................................................................................... 175

Figure A.8 – Discharge ....................................................................................................... 176

Figure A.9 – Characteristics ................................................................................................ 177

Figure A.10 – Follow on current pictures ............................................................................. 178

Figure B.1 – Typical EMC filter schematic ........................................................................... 180

Figure B.2 – 100 MΩ oscilloscope probes ........................................................................... 182

Figure B.3 – Combinations of EUT resistance and capacitance for 1-s time constant .......... 184

Figure B.4 – 240 V mains followed by capacitor discharge .................................................. 186

Figure B.5 – Time constant measurement schematic .......................................................... 187

Figure B.6 – Worst-case measured time constant values for 100 MΩ and 10 MΩ probes .... 191

Table 1 – General summary of required safeguards .............................................................. 20

Table 2 – Time/current zones for AC 15 Hz to 100 Hz for hand to feet pathway (see

IEC/TS 60479-1:2005, Table 11) ........................................................................................... 26

Table 3 – Time/current zones for DC for hand to feet pathway (see IEC/TS 60479-

1:2005, Table 13).................................................................................................................. 27

Table 4 – Limit values of accessible capacitance (threshold of pain) ..................................... 30

Table 5 – Total body resistances R for a current path hand to hand, DC, for large

surface areas of contact in dry condition ............................................................................... 32

Table 6 – Insulation requirements for external circuits .......................................................... 42

Table 7 – Voltage drop across clearance and solid insulation in series ................................. 47

Table 8 – Examples of application of various safeguards ...................................................... 77

---------------------- Page: 6 ----------------------
IEC TR 62368-2:2019 © IEC 2019 – 5 –
Table 9 – Basic safeguards against fire under normal operating conditions and

abnormal operating conditions .............................................................................................. 79

Table 10 – Supplementary safeguards against fire under single fault conditions ................... 80

Table 11 – Method 1: Reduce the likelihood of ignition ......................................................... 82

Table 12 – Method 2: Control fire spread .............................................................................. 91

Table 13 – Fire barrier and fire enclosure flammability requirements ..................................... 98

Table 14 – Summary – Fire enclosure and fire barrier material requirements ...................... 102

Table 15 – Control of chemical hazards .............................................................................. 107

Table 16 – Overview of requirements for dose-based systems ............................................ 132

Table 17 – Safety of batteries and their cells – requirements (expanded information on

documents and scope) ........................................................................................................ 151

Table B.1 – 100- MΩ oscilloscope probes ........................................................................... 182

Table B.2 – Capacitor discharge ......................................................................................... 183

Table B.3 – Maximum T values for combinations of R and C for
measured EUT EUT

T of 1 s ........................................................................................................................ 190

EUT
---------------------- Page: 7 ----------------------
– 6 – IEC TR 62368-2:2019 © IEC 2019
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
AUDIO/VIDEO, INFORMATION AND
COMMUNICATION TECHNOLOGY EQUIPMENT –
Part 2: Explanatory information related to IEC 62368-1:2018
FOREWORD

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6) All users should ensure that they have the latest edition of this publication.

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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is

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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.

The main task of IEC technical committees is to prepare International Standards. However, a

technical committee may propose the publication of a technical report when it has collected

data of a different kind from that which is normally published as an International Standard, for

example, "state of the art".

IEC 62368-2, which is a Technical Report, has been prepared by IEC technical committee

TC 108: Safety of electronic equipment within the field of audio/video, information technology

and communication technology.

This third edition updates the second edition of IEC 62368-2 published in 2014 to take into

account changes made to IEC 62368-1:2014 as identified in the Foreword of
IEC 62368-1:2018.

This Technical Report is informative only. In case of a conflict between IEC 62368-1 and IEC

TR 62368-2, the requirements in IEC 62368-1 prevail over this Technical Report.
---------------------- Page: 8 ----------------------
IEC TR 62368-2:2019 © IEC 2019 – 7 –
The text of this technical report is based on the following documents:
Enquiry draft Report on voting
108/708/DTR 108/711/RVDTR

Full information on the voting for the approval of this technical report can be found in the

report on voting indicated in the above table.
In this document, the following print types are used:
– notes/explanatory matter: in smaller roman type;

– tables and figures that are included in the rationale have linked fields (shaded in grey if

“field shading” is active);
– terms that are defined in IEC 62368-1: in bold type.

In this document, where the term (HBSDT) is used, it stands for Hazard Based Standard

Development Team, which is the Working Group of IEC TC 108 responsible for the
development and maintenance of IEC 62368-1.

This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

A list of all parts of the IEC 62368 series can be found, under the general title Audio/video,

information and communication technology equipment, on the IEC website.

In this document, only those subclauses from IEC 62368-1 considered to need further

background reference information or explanation to benefit the reader in applying the relevant

requirements are included. Therefore, not all numbered subclauses are cited. Unless

otherwise noted, all references are to clauses, subclauses, annexes, figures or tables located

in IEC 62368-1:2018.

The entries in the document may have one or two of the following subheadings in addition to

the Rationale statement:

Source – where the source is known and is a document that is accessible to the general

public, a reference is provided.

Purpose – where there is a need and when it may prove helpful to the understanding of the

Rationale, we have added a Purpose statement.
---------------------- Page: 9 ----------------------
– 8 – IEC TR 62368-2:2019 © IEC 2019

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