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IEC TR 62368-2
Edition 3.0 2019-05
REDLINE VERSION
TECHNICAL
REPORT
colour
inside
Audio/video, information and communication technology equipment –
Part 2: Explanatory information related to IEC 62368-1:20142018
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IEC TR 62368-2
Edition 3.0 2019-05
REDLINE VERSION
TECHNICAL
REPORT
colour
inside
Audio/video, information and communication technology equipment –
Part 2: Explanatory information related to IEC 62368-1: 20142018
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 33.160.01; 35.020 ISBN 978-2-8322-6916-9
– 2 – IEC TR 62368-2:2019 RLV © 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 . 73
7 Injury caused by hazardous substances. 108
8 Mechanically-caused injury . 112
9 Thermal burn injury. 120
10 Radiation . 129
Annex A Examples of equipment within the scope of this standard . 136
Annex B Normal operating condition tests, abnormal operating condition tests .
and single fault condition tests . 137
Annex C UV Radiation . 140
Annex D Test generators . 140
Annex E Test conditions for equipment containing audio amplifiers . 140
Annex F Equipment markings, instructions, and instructional safeguards . 141
Annex G Components . 142
Annex H Criteria for telephone ringing signals . 150
Annex J Insulated winding wires for use without interleaved insulation . 152
Annex K Safety interlocks . 152
Annex L Disconnect devices . 152
Annex M Equipment containing batteries and their protection circuits . 153
Annex O Measurement of creepage distances and clearances . 162
Annex P Safeguards against conductive objects . 162
Annex Q Circuits intended for interconnection with building wiring . 163
Annex R Limited short-circuit test . 164
Annex S Tests for resistance to heat and fire . 164
Annex T Mechanical strength tests . 166
Annex U Mechanical strength of CRTs and protection against the effects of
implosion . 167
Annex V Determination of accessible parts . 167
Annex X Alternative method for determing clearances for insulation in circuits
connected to an AC mains not exceeding 420 V peak (300 V RMS) . 168
Annex Y Construction requirements for outdoor enclosures . 168
Annex A (informative) Background information related to the use of SPDs . 171
Annex B (informative) Background information related to measurement of discharges
– Determining the R-C discharge time constant for X- and Y-capacitors . 185
Annex C (informative) Background information related to resistance to candle flame
ignition . 196
Bibliography . 197
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 . 20
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 . 41
Figure 12 – Illustration of transient voltages on paired conductor external circuits . 43
Figure 13 – Illustration of transient voltages on coaxial-cable external circuits . 44
Figure 14 – Basic and reinforced insulation in Table 15 14 of IEC 62368-1:20142018;
ratio reinforced to basic . 46
Figure 15 – Reinforced clearances according to Rule 1, Rule 2, and Table 15 14 . 48
Figure 16 – Example illustrating accessible internal wiring . 56
Figure 17 – Waveform on insulation without surge suppressors and no breakdown . 59
Figure 18 – Waveforms on insulation during breakdown without surge suppressors . 59
Figure 19 – Waveforms on insulation with surge suppressors in operation . 60
Figure 20 – Waveform on short-circuited surge suppressor and insulation . 60
Figure 21 – Example for an ES2 source . 62
Figure 22 – Example for an ES3 source . 62
Figure 23 – Overview of protective conductors . 64
Figure 24 – Example of a typical touch current measuring network . 67
Figure 25 – Touch current from a floating circuit . 69
Figure 26 – Touch current from an earthed circuit . 70
Figure 27 – Summation of touch currents in a PABX . 70
Figure 28 – Possible safeguards against electrically-caused fire . 78
Figure 29 – Fire clause flow chart . 81
Figure 30 – Prevent ignition flow chart . 86
Figure 31 – Control fire spread summary . 88
Figure 32 – Control fire spread PS2 . 89
Figure 33 – Control fire spread PS3 . 90
Figure 34 – Fire cone application to a large component . 99
Figure 35 – Flowchart demonstrating the hierarchy of hazard management . 111
Figure 36 – Model for chemical injury . 112
Figure 37 – Direction of forces to be applied . 117
Figure 38 – Model for a burn injury . 120
– 4 – IEC TR 62368-2:2019 RLV © IEC 2019
Figure 39 – Model for safeguards against thermal burn injury . 122
Figure 40 – Model for absence of a thermal hazard . 123
Figure 41 – Model for presence of a thermal hazard with a physical safeguard in place . 123
Figure 42 – Model for presence of a thermal hazard with behavioural safeguard
in place . 123
Figure 43 – Flowchart for evaluation of Image projectors (beamers) . 131
Figure 44 – Graphical representation of L ,T . 133
Aeq
Figure 45 – Overview of operating modes . 139
Figure 46 – Voltage-current characteristics (Typical data) . 143
Figure 47 – Example of IC current limiter circuit . 148
Figure 48 – Current limit curves . 151
Figure 49 – Example of a dummy battery circuit . 161
Figure 50 – Example of a circuit with two power sources.
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