IEC TR 62368-2:2019 is available as /2 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

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4	Audio/video, information and communication technology equipment – Part 2: Explanatory information related to IEC 62368-1:2018
5	ii CONTENTS
7	iv
9	vi INTERNATIONAL ELECTROTECHNICALCOMMISSION FOREWORD
11	viii
12	INTRODUCTION
13	x AUDIO/VIDEO, INFORMATION AND Clause 0 Principles of this product safety standard 0.5.1 General
14	Figure 1 – Risk reduction as given in ISO/IEC Guide 51
15	Figure 2 – HBSE Process Chart Clause 1 Scope
16	Clause 2 Normative references Clause 3 Terms, definitions and abbreviations 3.3.2.1 electrical enclosure
17	3.3.5.1 basic insulation 3.3.5.2 double insulation 3.3.5.53.3.5.6 solid insulation 3.3.5.6 3.3.5.7 supplementary insulation 3.3.6.73.3.6.9 restricted access area 3.3.7.83.3.7.7 reasonably foreseeable misuse
18	3.3.8.1 instructed person 3.3.8.3 skilled person 3.3.11.9 protective bonding conductor Figure 3 – Protective bonding conductor as part of a safeguard 3.3.14.43.3.14.3 prospective touch voltage 3.3.14.93.3.14.8 working voltage working voltage.
19	3.3.15.2 class II construction Clause 4 General requirements Reasonable foreseeable misuse functional insulation functional components
20	4.1.1 Application of requirements and acceptance of materials, components and subassemblies Acceptance of components and component requirements from IEC 60065 and IEC 60950-1 4.1.5 Constructions and components not specifically covered
21	4.1.6 Orientation during transport and use 4.1.8 Liquids and liquid filled components (LFC) 4.2 Energy source classifications 4.2.1 Class 1 energy source 4.2.2 Class 2 energy source – a skilled person.
22	4.2.3 Class 3 energy source 4.3.2 Safeguards for protection of an ordinary person Figure 4 – Safeguards for protecting an ordinary person Figure 5 – Safeguards for protecting an instructed person
23	4.3.4 Safeguards for protection of a skilled person Figure 6 Safeguards for protecting a skilled person Table 1 – General summary of required safeguards 4.4.2 Composition of a safeguard
24	4.4.44.4.3 Safeguard robustness 4.4.3.44.4.3.4 Impact test 4.4.3.6 Glass impact tests
26	4.6 Fixing of conductors 4.7 Equipment for direct insertion into mains socket-outlets 4.9 Likelihood of fire or shock due to entry of conductive objects Clause 5 Electrically-caused injury
28	5.2.1 Electrical energy source classifications Figure 18 – Conventional time/current zones of effects
29	Table 2 – Time/current zones for a.c.AC 15 Hz to 100 Hz
30	Table 3 – Time/current zones for DC for hand to feet pathway (see IEC TS 60479-1:2005, Table 13)
31	Figure 310 – Illustration that limits depend on both voltage and current 5.2.2.1 General 5.2.2.2 Steady-state voltage and current limits
33	5.2.2.3 Capacitance limits Table 4 – Limit values of accessible capacitance (threshold of pain)
34	Table 7 Current limits for single pulses
36	5.2.2.7 Audio signals 5.3.2 Accessibility to electrical energy sources and safeguards
37	5.3.2.2 Contact requirements
38	5.3.2.3 Compliance criteria 5.3.2.4 Terminals for connecting stripped wire 5.4 Insulation materials and requirements 5.4.1.1 Insulation 5.4.1.4 Maximum operating temperatures for materials, components and systems
39	5.4.1.5 Pollution degrees 5.4.1.5.2 Test for pollution degree 1 environment and for an insulating compound 5.4.1.6 Insulation in transformers with varying dimensions 5.4.1.7 Insulation in circuits generating starting pulses 5.4.1.8 Determination of working voltage
40	5.4.1.8.1 General 5.4.1.8.2 RMS working voltage 5.4.1.8.3 Peak working voltage 5.4.1.8.2 RMS working voltage 5.4.1.10 Thermoplastic parts on which conductive metallic parts are directly mounted 5.4.2 Clearances
42	5.4.2.2 Procedure 1 for determining clearance using Peak of the working voltage versus recurring peak voltage. Figure 11 – Illustration of working voltage
43	5.4.2.3.2.2 Determining a.c.AC mains transient voltages 5.4.2.3.2.3 Determining DC mains transient voltages 5.4.2.3.2.4 Determining external circuit transient voltages
44	Figure 412 – Illustration of transient voltages on paired conductor external circuits
45	5.4.2.3.2.3 Determining d.c. mains transient voltages 5.4.2.3.2.5 Determining transient voltage levels by measurement 5.4.2.3.4 Determining clearances using required withstand voltage Table 15 – 14 Minimum clearances using required withstand voltage
46	Figure 614 – Basic and reinforced insulation in Table 1514 of IEC 62368-1:2014 – Ratio2018; ratio reinforced to basic
47	Figure 715 – Reinforced clearances according to Rule 1, Rule 2, and Table 1514
48	5.4.2.4 Determining the adequacy of a clearance using an electric strength test
49	Table 7 – Voltage drop across clearance and solid insulation in series 5.4.2.6 Compliance criteria
50	5.4.3 Creepage distances 5.4.3.2 Test method 5.4.3.3 Material group and CTI
51	5.4.3.4 Compliance criteria 5.4.4 Solid insulation 5.4.4.2 Minimum distance through insulation 5.4.4.3 Insulating compound forming solid insulation
52	5.4.4.4 Solid insulation in semiconductor devices 5.4.4.5 Insulating compound forming cemented joints 5.4.4.6.1 General requirements reinforced insulation. 5.4.4.6.2 Separable thin sheet material reinforced insulation. 5.4.4.6.3 Non-separable thin sheet material
53	5.4.4.6.4 Standard test procedure for non-separable thin sheet material 5.4.4.6.5 Mandrel test 5.4.4.7 Solid insulation in wound components 5.4.4.9 Solid insulation requirements at frequencies higher than 30 kHz 5.3.2.2.1 Frequency of the voltage
54	5.4.5 Antenna terminal insulation 5.4.6 Insulation of internal wire as a part of a supplementary safeguard Figure 816 – Example illustrating accessible internal wiring 5.4.7 Tests for semiconductor components and for cemented joints
55	5.4.8 Humidity conditioning 5.4.9 Electric strength test Table 26 – 25 Test voltages for electric strength tests based on transient voltages Table 27 – 26 Test voltages for electric strength tests based on the peak of the working voltages and recurring peak voltages Table 28 – 27 Test voltages for electric strength tests based on temporary overvoltages 5.4.10 Safeguards against transient voltages from external circuits
56	5.4.10.2.2 Impulse test
57	Figure 917 – Waveform on insulation without surge suppressors and no breakdown Figure 10 18 – Waveforms on insulation during breakdown without surge suppressors Figure 11 19 – Waveforms on insulation with surge suppressors in operation
58	5.4.11 Separation between external circuits and earth 5.5 Components as safeguards
59	Figure 1321 – Example for an ES2 source Figure 1422 – Example for an ES3 source
60	for double insulation or reinforced insulation. 5.5.2.1 General requirements 5.5.2.2 Safeguards against capacitorCapacitor discharge after disconnection of a connector
61	5.5.6 Resistors 5.5.7 SPDs 5.5.8 Insulation between the mains and an external circuit consisting of a coaxial cable 5.6 Protective conductor Figure 1523 – Overview of protective conductors
62	5.6.1 General 5.6.2.2 Colour of insulation 5.6.3 Requirements for protective earthing conductors 5.6.4 Requirements for protective bonding conductors
63	5.6.5 Terminals for protective conductors 5.6.6.2 Test method 5.6.7 Reliable connection of a protective earthing conductor For stationary pluggable equipment type A where a skilled person verifies the proper connection of the earth conductor. 5.7 Prospective touch voltage, touch current and protective conductor current 5.7 3 Equipment set-up, supply connections and earth connections
64	5.7.45.7. 5 Earthed accessible conductive parts Figure 1624 – Example of a typical touch current measuring network 5.7.7 Prospective touch voltage and touch current due toassociated with external circuits
65	5.7.6.25.7.7.2 Prospective touch voltage and touch current to external circuitsassociated with paired conductor cables 5.7.75.7.8 Summation of touch currents from external circuits a) Touch current from external circuits
66	a.1) Floating circuits Figure 25 17 – Touch current from a floating circuit a.2) Earthed circuits Figure 1826 – Touch current from an earthed circuit b) Interconnection of several equipments
67	Figure 1927 – Summation of touch currents in a PABX b.1) Isolation b.2) Common return, isolated from earth b.3) Common return, connected to protective earth
68	Fault testing Relays Electronic protection Mechanical protection
69	Control circuitry Clause6 Electrically-caused fire 6.2 Classification of power sources (PS) and potential ignition sources (PIS) 6.2.2 Power source circuit classifications
70	6.2.2.2 Power measurement for worst-case fault 6.2.2.3 Power measurement for worst-case power source fault 6.2.2.4 PS1
71	6.2.2.5 PS2 6.2.2.6 PS3 6.2.3 Classification of potential ignition sources
72	6.2.3.1 Arcing PIS 6.2.3.2 Resistive PIS
73	6.3 Safeguards against fire under normal operating conditions and abnormal operating conditions Figure 2028 – Possible safeguards against electrically-caused fire
74	Methods of protection B) Protection under single fault conditions
75	Table 8 – Examples of application of various safeguards
76	Figure 2129 – Fire clause flow chart
77	Table 9 – Basic safeguards against fire under normal operating conditions and abnormal operating conditions 6.3.2 Compliance criteria 6.4 Safeguards against fire under single fault conditions
78	Table 10 – Supplementary safeguards against fire under single fault conditions
79	Table 11 – Method 1: Reduce the likelihood of ignition
80	Figure 2230 – Prevent ignition flow chart
81	Figure 23 31 – Control fire spread summary
82	Figure 2432 – Control fire spread PS2
83	Figure 3325(Control fire spread S3
84	6.4.2 Reduction of the likelihood of ignition under single fault conditions in PS1 circuits 6.4.3 Reduction of the likelihood of ignition under single fault conditions in PS2 circuits and PS3 circuits 6.4.3.26.4.3.1 Requirements
85	6.4.3.36.4.3.2 Test method 6.4.4 Control of fire spread in PS1 circuits
86	Table 12 – Method 2: Control fire spread
87	6.4.5 Control of fire spread in PS2 circuits
88	6.4.5.2 Requirements
89	6.4.5.3 Compliance criteria 6.4.6 Control of fire spread in a PS3 circuit 6.4.7 Separation of combustible materials from a PIS 6.4.7.2 Separation by distance
91	Figure 2634 – Fire cone application to a large component Figure 37 Minimum separation requirements from an arcinga PIS Figure 38 Extended separation requirements from a PIS Figure 39 – Rotated separation requirements due to forced air flow 6.4.7.3 Separation by a fire barrier
92	Figure 40 – 39 Deflected separation requirements from a PIS when a fire barrier is used 6.4.8 Fire enclosures and fire barriers Table 13 – Fire barrier and fire enclosure flammability requirements
93	6.4.8.2.2 Requirements for a fire enclosure 6.4.8.2.3 Compliance criteria 6.4.8.3 Constructional requirements for a fire enclosure and a fire barrier 6.4.8.3.1 Fire enclosure and fire barrier openings Figure 40 Determination of top, bottom and side openings 6.4.8.3.2 Fire barrier dimensions
94	6.4.8.3.3 Top openings and top opening properties 6.4.8.3.4 Bottom openings and bottom opening properties
95	Table 14 – Summary – Fire enclosure and fire barrier material requirements
96	6.4.8.3.6 Integrity of the a fire enclosure 6.4.8.3.66.4.8.3.7 Compliance criteria 6.4.8.4 Separation of a PIS from a fire enclosure and a fire barrier
97	6.5.2 Compliance criteria1General requirements 6.5.36.5.2 Requirements for interconnection to building wiring
98	6.6 Safeguards against fire due to the connection of additional equipment Clause7 Injury caused by hazardous substances Energy source:
99	Transfer mechanism: Injury: Table 15 – Control of chemical hazards
100	Figure 2735 – Flowchart demonstrating the hierarchy of hazard management
101	Figure 2836 – Model for chemical injury Clause 8 Mechanically-caused injury 8.1 General 8.2 Mechanical energy source classifications 8.2.1 General classification
102	Line 4 – Loosening, exploding or imploding parts Line 5 – Equipment mass Line 6 – Wall/ceiling or other structure mount Notes b and c 8.2.2 MS1 8.2.3 MS2 8.2.4 MS3 8.3 Safeguards against mechanical energy sources
103	8.4 Safeguards against parts with sharp edges and corners 8.5 Safeguards against moving parts 8.5.1 Requirements
104	8.6 Stability of equipment 8.6.2.2 Static stability test
105	8.6.2.3 Downwards force test 8.6.3 Relocation stability test 8.6.4 Glass slide test 8.6.5 Horizontal force test and compliance criteria 8.7 Equipment mounted to a wall or , ceiling or other structure
106	8.7.2 Test methods Figure 2937 – Direction of forces to be applied Table 37 Torque to be applied to screws 8.8 Handle strength 8.8.2 Test method and compliance criteria 8.9 Wheels or casters attachment requirements
107	8.10 Carts, stands, and similar carriers 8.10.1 General 8.10.2 Marking and instructions 8.10.3 Cart, stand or carrier loading test and compliance criteria 8.10.4 Cart, stand or carrier impact test 8.10.5 Mechanical stability 8.10.6 Thermoplastic temperature stability 8.11 Mounting means for rackslide-rail mounted equipment (SRME)
108	8.11.3 Mechanical strength test 8.11.4 Mechanical strength test, 250 N, including 8.11.3.2 Lateral push foce test Clause 9 Thermal burn injury 9.1 General
109	B Model for a burn injury Figure 3038 – Model for a burn injury
110	C Types of burn injuries D Model for safeguards against thermal burn injury Figure 31 39 – Model for safeguards against thermal burn injury
111	Safeguards overview Figure 32 40 – Model for absence of a thermal hazard Figure 3341 – Model for presence of a thermal hazard with a physical safeguard in place
112	Figure 3442 – Model for presence of a thermal hazard with behavioural safeguard in place 9.2.29.2. TS11TS1 9.2.39.2.2 TS2 9.2.49.2.3 TS3 9.2.4 TS3
113	9.2.69.3 Touch temperature levelslimits Contact time duration > 8 h
114	Other considerations Factors for consideration in determining test conditions
115	9.3.1 Touch temperature limit requirements 9.3.2 Test method and compliance criteria
116	9.39.4 Safeguards against thermal energy sources 9.4.19.5.1 Equipment safeguard 9.4.29.5.2 Instructional safeguard Clause 10 Radiation
117	Table 16 – Protection against radiation 9.6 Requirements for wireless power transmitters 9.6.3 Test method and compliance criteria 10 Radiation 10.2 Radiation energy source classifications Table 39 – 10.2.1 General classification Rationale: Radiation energy source classifications Line 2 – for X-rays and acoustics are given in Table 39. For optical radiation (“Lasers” and “Lamps and LED’s
118	Figure 43 – Flowchart for evaluation of Image projectors (beamers) 10.2.4 RS3 10.3 Safeguards against laser radiation
119	10.4 Safeguards against visible, infra-red, and ultra-violetoptical radiation from lamps and lamp systems (including LED types) 10.4.1 General Requirements 10.5 Safeguards against X-radiation 10.6 Safeguards against acoustic energy sources
120	Figure 44 – Graphical representation of LAeq,T 10.6.3 Requirements for dose-based systems
121	Table 16 – Overview of requirements for dose-based systems
122	10.6.5.110.6.6.1 Corded listening devices with analogue input Annex A Examples of equipment within the scope of this standard
123	Annex B Normal operating condition tests, abnormal operating condition tests and single fault condition tests General Equipment safeguards during various operating conditions
125	B.1.6B.1.5 Temperature measurement conditions B.2.3 Supply Voltage B.2 – B.3 – B.4 Operating modes
126	Figure 3645 – Overview of operating modes B.4.4 Functional insulation B.4.8 Compliance criteria during and after single fault conditions Annex C UV Radiation C.1.1 General Annex D Test generators
127	Annex E Test conditions for equipment containing audio amplifiers Annex F Equipment markings, instructions, and instructional safeguards F.3 Equipment markings F.3.3.2 Equipment without direct connection to mains
128	F.3.6.2 Class II Equipment class marking F.4 Instructions F.5 Instructional safeguards Annex G Components G.1 Switches G.2.1 Requirements G.3.3 PTC thermistors
129	G.3.4 Overcurrent protective devices
130	G.3.5 Safeguard components not mentioned in G.3.1 to G.3.4 G.5.1 Wire insulation in wound components G.5.2 Endurance test G.5.2.2 Heat run test G.5.3 Transformers G.5.3.3 Transformer overload tests Table G.3 Temperature limits for transformer windings and for motor windings (except for the motor running overload test)
131	G.5.3.4 Transformers using fully insulated winding wire (FIW) G.5.4 Motors G.7 Mains supply cords
132	G.7.3 – G.7.5 Mains supply cord anchorage, cord entry, bend protection G.8 Varistors G.9 Integrated circuit (IC) current limiters
133	Figure 47 – Example of IC current limiter circuit G.11 Capacitors and RC units
134	G.13 Printed boards G.13.6 Tests on coated printed boards G.14 Coatings on component terminals G.15 Pressurized liquid filled components
135	Annex H Criteria for telephone ringing signals H.2 Method A
136	Figure 3848 – Current limit curves H.3 Method B
137	Annex J Insulated winding wires for use without interleaved insulation Annex K Safety interlocks Annex L Disconnect devices
138	Annex M Equipment containing batteries and their protection circuits M.1 General requirements M.2 Safety of batteries and their cells ordinary person or an instructed person.
139	Table 17 – Safety of batteries and their cells – requirements (expanded information on documents and scope)
144	M.3 Protection circuits for batteries provided within the equipment M.4 Additional safeguards for equipment containing a portable secondary lithium battery M.4.2.2 Compliance criteria
145	Figure 3949 – Example of a dummy battery circuit M.4.4 Drop test of equipment containing a secondary lithium battery
146	M.6.1.1 General requirementsRequirements M.7.1 Ventilation preventing an explosive gas concentration M.7.2 Test method and compliance criteria M.8.2.1 General Annex O Measurement of creepage distances and clearances Annex P Safeguards against conductive objects P.1 General P.2 Safeguards against entry or consequences of entry of a foreign object
147	P.2.3.1 SafeguardsSafeguard requirements P.3 Safeguards against spillage of internal liquids P.4 Metalized coatings and adhesives securing parts Annex Q Circuits intended for interconnection with building wiring
148	Q.1.2 Test method and compliance criteria Q.2 Test for external circuits – paired conductor cable Figure 4050 – Example of a circuit with two power sources Annex R Limited short-circuit test Annex S Tests for resistance to heat and fire S.1 Flammability test for fire enclosure and fire barrier materials of equipment where the steady-state power does not exceed 4 000 W
149	S.2 Flammability test for fire enclosure and fire barrier integrity S.3 Flammability tests for the bottom of a fire enclosure S.4 Flammability classification of materials
150	S.5 Flammability test for fire enclosure materials of equipment with a steady state power exceeding 4 000 W Annex T Mechanical strength tests T.2 Steady force test, 10 N T.3 Steady force test, 30 N T.4 Steady force test, 100 N T.5 Steady force test, 250 N T.6 Enclosure impact test T.7 Drop test
151	T.8 Stress relief test T.9 ImpactGlass impact test T.10 Glass fragmentation test Annex U Mechanical strength of CRTs and protection against the effects of implosion U.2 Test method and compliance criteria for non-intrinsically protected CRTs Annex V Determination of accessible parts Figure V.3 Blunt probe
152	Annex X Alternative method for determing clearances for insulation in Annex Y Construction requirements for outdoor enclosures
153	Electric shock Fire Mechanical hazards Heat-related hazards
154	Radiation Chemical hazards Biological hazards Explosion hazards Y.3 Resistance to corrosion Y.4.6 Securing means
155	Annex A (informative) A.1 Industry demand for incorporating SPDs in the equipment
156	Figure A.1 – Installation has poor earthing and bonding; equipment damaged (from ITU-T K.66)
157	Figure A.3 – Installation with poor earthing and bonding, using a varistor and a GDT for protection against a lightning strike
158	A.3 Technical discussion A.3.1 General Figure A.5 – Safeguards
159	A.3.3 Consideration of a GDT and its follow current A.3.4 Consideration of varistors and its leak current A.3.5 Surge voltage/current from mains A.3.5.2 Case of longitudinal transient on primary circuit
160	A.3.6 Surge voltage/current from external circuits A.3.6.2 Case of longitudinal transient on external circuits A.3.7 Summary A.4 Information about follow current (or follow-on current) A.4.1 General
161	A.4.2 What is follow-on-current? A.4.3 What are the V-I properties of discharge tubes?
162	Figure A.6 – Discharge stages Glow discharge Arc discharge A.4.4 What is holdover?
163	Figure A.7 – holdoverHoldover
164	Figure A.8 – Discharge A.4.5 Follow-on-current from AC sources?
165	Figure A.9 – Characteristics
166	Figure A.10 – Follow on current pictures A.4.6 Applications with a high risk of follow-on-current
167	Annex B (informative) B.1 General B.2 EMC filters Figure B.1 – Typical EMC filter schematic
168	B.4 The requirement B.5 100 MΩ probes Table B.1 – 100 MΩoscilloscope probes
169	Figure B.2 – 100 MΩ oscilloscope probes B.6 The R-C time constant and its parameters Table B.2 – Capacitor discharge
171	Figure B.3 – Combinations of EUT resistance and capacitance for 1 s time constant B.7 Time constant measurement.
172	Figure B.4 – 240 V mains followed by capacitor discharge
173	Figure B.5 – Time constant measurement schematic
174	B.8 Effect of probe resistance B.9 Effect of probe capacitance
175	B.10 Determining the time constant
177	Figure B.6 – Worst-case measured time constant values for 100 MΩ and 10 MΩ probes
178	Annex C (informative)
179	Bibliography
182	undefined
184	English CONTENTS
188	FOREWORD
191	INTRODUCTION
192	0 Principles of this product safety standard
193	Figures Figure 1 – Risk reduction as given in ISO/IEC Guide 51
194	1 Scope Figure 2 – HBSE Process Chart
195	2 Normative references 3 Terms, definitions and abbreviations
197	Figure 3 – Protective bonding conductor as part of a safeguard
198	4 General requirements
201	Figure 4 – Safeguards for protecting an ordinary person Figure 5 – Safeguards for protecting an instructed person
202	Figure 6 – Safeguards for protecting a skilled person Tables Table 1 – General summary of required safeguards
204	Figure 7 – Flow chart showing the intent of the glass requirements
205	5 Electrically-caused injury
207	Figure 8 – Conventional time/current zones of effects of AC currents (15 Hz to 100 Hz) on persons for a current path correspondingto left hand to feet (see IEC TS 60479-1:2005, Figure 20)
208	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) 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)
209	Figure 10 – Illustration that limits depend on both voltage and current Table 3 – Time/current zones for DC for hand to feet pathway (see IEC TS 60479-1:2005, Table 13)
212	Table 4 – Limit values of accessible capacitance (threshold of pain)
214	Table 5 – Total body resistances RT for a current path hand to hand, DC, for large surface areas of contact in dry condition
221	Figure 11 – Illustration of working voltage
223	Figure 12 – Illustration of transient voltages on paired conductor external circuits
224	Figure 13 – Illustration of transient voltages on coaxial-cable external circuits Table 6 – Insulation requirements for external circuits
225	Figure 14 – Basic and reinforced insulation in Table 14 of IEC 62368-1:2018; ratio reinforced to basic
227	Figure 15 – Reinforced clearances according to Rule 1, Rule 2, and Table 14
229	Table 7 – Voltage drop across clearance and solid insulation in series
235	Figure 16 – Example illustrating accessible internal wiring
238	Figure 17 – Waveform on insulation without surge suppressors and no breakdown
239	Figure 18 – Waveforms on insulation during breakdown without surge suppressors Figure 19 – Waveforms on insulation with surge suppressors in operation Figure 20 – Waveform on short-circuited surge suppressor and insulation
241	Figure 21 – Example for an ES2 source Figure 22 – Example for an ES3 source
243	Figure 23 – Overview of protective conductors
246	Figure 24 – Example of a typical touch current measuring network
248	Figure 25 – Touch current from a floating circuit
249	Figure 26 – Touch current from an earthed circuit Figure 27 – Summation of touch currents in a PABX
252	6 Electrically-caused fire
257	Figure 28 – Possible safeguards against electrically-caused fire
259	Table 8 – Examples of application of various safeguards
260	Figure 29 – Fire clause flow chart
261	Table 9 – Basic safeguards against fire under normal operating conditions and abnormal operating conditions
262	Table 10 – Supplementary safeguards against fire under single fault conditions
264	Table 11 – Method 1: Reduce the likelihood of ignition
265	Figure 30 – Prevent ignition flow chart
267	Figure 31 – Control fire spread summary
268	Figure 32 – Control fire spread PS2
269	Figure 33 – Control fire spread PS3
273	Table 12 – Method 2: Control fire spread
278	Figure 34 – Fire cone application to a large component
280	Table 13 – Fire barrier and fire enclosure flammability requirements
284	Table 14 – Summary – Fire enclosure and fire barrier material requirements
287	7 Injury caused by hazardous substances
289	Table 15 – Control of chemical hazards
290	Figure 35 – Flowchart demonstrating the hierarchy of hazard management
291	8 Mechanically-caused injury Figure 36 – Model for chemical injury
296	Figure 37 – Direction of forces to be applied
299	9 Thermal burn injury Figure 38 – Model for a burn injury
301	Figure 39 – Model for safeguards against thermal burn injury
302	Figure 40 – Model for absence of a thermal hazard Figure 41 – Model for presence of a thermal hazard with a physical safeguard in place Figure 42 – Model for presence of a thermal hazard with behavioural safeguard in place
308	10 Radiation
310	Figure 43 – Flowchart for evaluation of Image projectors (beamers)
312	Figure 44 – Graphical representation of LAeq,T
314	Table 16 – Overview of requirements for dose-based systems
315	Annexes Annex A Examples of equipment within the scope of this standard Annex B Normal operating condition tests, abnormal operating condition tests and single fault condition tests
317	Figure 45 – Overview of operating modes
318	Annex C UV Radiation Annex D Test generators
319	Annex E Test conditions for equipment containing audio amplifiers Annex F Equipment markings, instructions, and instructional safeguards
320	Annex G Components
322	Figure 46 – Voltage-current characteristics (Typical data)
326	Figure 47 – Example of IC current limiter circuit
328	Annex H Criteria for telephone ringing signals
329	Figure 48 – Current limit curves
330	Annex J Insulated winding wires for use without interleaved insulation Annex K Safety interlocks Annex L Disconnect devices
331	Annex M Equipment containing batteries and their protection circuits
333	Table 17 – Safety of batteries and their cells – requirements (expanded information on documents and scope)
339	Figure 49 – Example of a dummy battery circuit
340	Annex O Measurement of creepage distances and clearances Annex P Safeguards against conductive objects
341	Annex Q Circuits intended for interconnection with building wiring
342	Annex R Limited short-circuit test Annex S Tests for resistance to heat and fire Figure 50 – Example of a circuit with two power sources
344	Annex T Mechanical strength tests
345	Annex U Mechanical strength of CRTs and protection against the effects of implosion Annex V Determination of accessible parts
346	Annex X Alternative method for determing clearances for insulation in circuits connected to an AC mains not exceeding 420 V peak (300 V RMS) Annex Y Construction requirements for outdoor enclosures
349	Annex A (informative) Background information related to the use of SPDs
350	Figure A.1 – Installation has poor earthing and bonding; equipment damaged (from ITUT K.66) Figure A.2 – Installation has poor earthing and bonding; using main earth bar for protection against lightning strike (from ITU-T K.66)
351	Figure A.3 – Installation with poor earthing and bonding, using a varistor and a GDT for protection against a lightning strike Figure A.4 – Installation with poor earthing and bonding; equipment damaged (TV set)
352	Figure A.5 – Safeguards
356	Figure A.6 – Discharge stages
357	Figure A.7 – Holdover
358	Figure A.8 – Discharge
359	Figure A.9 – Characteristics
360	Figure A.10 – Follow on current pictures
362	Annex B (informative) Background information related to measurement of discharges – Determining the R-C discharge time constant for X- and Y-capacitors Figure B.1 – Typical EMC filter schematic
364	Figure B.2 – 100 MΩ oscilloscope probes Table B.1 – 100 MΩ oscilloscope probes
365	Table B.2 – Capacitor discharge
366	Figure B.3 – Combinations of EUT resistance and capacitance for 1 s time constant
368	Figure B.4 – 240 V mains followed by capacitor discharge
369	Figure B.5 – Time constant measurement schematic
372	Table B.3 – Maximum Tmeasured values for combinations of REUT and CEUT for TEUT of 1 s
373	Figure B.6 – Worst-case measured time constant values for 100 MΩ and 10 MΩ probes
374	Annex C (informative) Background information related to resistance to candle flame ignition
375	Bibliography

Published By	Publication Date	Number of Pages
BSI	2020	378


PDF Format	Searchable	Printable	Preview Now

Status	Definitive
Pages	378
Publication Date	2020-02-24
ISBN	978 0 539 07427 7
Standard Number	PD IEC TR 62368-2:2019 – TC
Title	Tracked Changes. Audio/video, information and communication technology equipment – Explanatory information related to IEC 62368-1:2018
Descriptors	Safety measures, Communication equipment, Hazards, Audio equipment, Data processing, Fire safety, Computers, Electrical safety, Video recording, Television equipment, Electrical components, Electronic equipment and components
Publisher	BSI
Committee	EPL/108
ICS Codes	33.160.01 - Audio, video and audiovisual systems in general

BSI PD IEC TR 62368-2:2019 – TC:2020 Edition

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