Audio/video, information and communication technology equipment - Part 3: Safety aspects for DC power transfer through communication cables and ports

IEC 62368-3:2017 applies to equipment intended to supply and receive operating power through communication cables or ports. It covers particular requirements for circuits that are designed to transfer DC power from a power sourcing equipment (PSE) to a powered device (PD).
The power transfer uses voltages at ES1 or ES2 or in very specific cases voltage levels at ES3.
Any cable provided with a connector defined by an industry standard that permits DC power transfer between equipment is considered a communication cable even if communication does not take place. For example, a USB cable can be used just to recharge a portable device battery.
This International Standard is to be used in conjunction with IEC 62368-1:2014.
It has the status of a group safety publication in accordance with IEC Guide 104.
The subclauses of IEC 62368-1 apply as far as reasonable. Where safety aspects are similar to those of IEC 62368-1, the relevant clause or subclause of IEC 62368-1 is given for reference in a note in the relevant subclause. Where a requirement in IEC 62368-3 refers to a requirement or criterion of IEC 62368-1, a specific reference to IEC 62368-1 is made.
This group safety publication is primarily intended to be used as a product safety standard for the products mentioned in the scope, but shall also be used by technical committees in the preparation of standards for products similar to those mentioned in the scope of this standard, in accordance with the principles laid down in IEC Guide 104 and lSO/lEC Guide 51.

Equipements des technologies de l'audio/vidéo, de l'information et de la communication - Partie 3: Aspects liés à la sécurité relatifs au transfert de puissance en courant continu au moyen de câbles et d’accès de communication

IEC 62368-3:2017 s’applique aux équipements conçus pour fournir et recevoir de l’énergie de fonctionnement au moyen de câbles et d’accès de communication. Elle couvre les exigences particulières relatives aux circuits conçus pour transférer de la puissance en courant continu d’un équipement source d’alimentation (PSE - power sourcing equipment) à un dispositif alimenté (PD - powered device).
Le transfert de puissance utilise des tensions à ES1 ou ES2 ou, dans des cas très spécifiques, des niveaux de tensions à ES3.
Tout câble équipé d’un connecteur défini par une norme industrielle permettant le transfert de puissance en courant continu entre des équipements est considéré comme étant un câble de communication, même en l’absence de communication. Par exemple, un câble USB peut être utilisé uniquement pour recharger une batterie de dispositif portable.
Cette Norme Internationale doit être utilisée conjointement avec l'IEC IEC 62368-1:2014.
Elle a le statut d'une publication groupée de sécurité conformément au Guide IEC 104.
Les paragraphes de l’IEC 62368-1 s’appliquent dans la mesure du possible. Lorsque les aspects liés à la sécurité sont similaires à ceux décrits dans l’IEC 62368-1, l’article ou le paragraphe pertinent de l’IEC 62368-1 est indiqué à titre de référence dans une note qui figure dans le paragraphe concerné. Lorsqu’une exigence de l’IEC 62368-3 fait référence à une exigence ou un critère de l’IEC 62368-1, une référence particulière est faite à l’IEC 62368-1.
La présente publication groupée de sécurité est avant tout destinée à être utilisée en tant que norme en matière de sécurité des produits pour les produits cités dans le domaine d’application, mais elle doit également être utilisée par les comités d’études dans le cadre de l’élaboration de normes pour des produits similaires à ceux cités dans le domaine d’application de la présente norme, conformément aux principes établis dans le Guide IEC 104 et le Guide ISO/IEC 51.
Mots clés: communication, sécurité, câbles, transfert de puissance en courant continu

General Information

Status
Published
Publication Date
06-Dec-2017
Current Stage
PPUB - Publication issued
Completion Date
07-Dec-2017
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IEC 62368-3
Edition 1.0 2017-12
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
GROUP SAFETY PUBLICATION
PUBLICATION GROUPÉE DE SÉCURITÉ
Audio/video, information and communication technology equipment –
Part 3: Safety aspects for DC power transfer through communication cables and
ports
Équipements des technologies de l’audio/vidéo, de l’information et de la
communication –

Partie 3: Aspects liés à la sécurité relatifs au transfert de puissance en courant

continu au moyen de câbles et d’accès de communication
IEC62368-3:2017-12(en-fr)
---------------------- Page: 1 ----------------------
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---------------------- Page: 2 ----------------------
IEC 62368-3
Edition 1.0 2017-12
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
GROUP SAFETY PUBLICATION
PUBLICATION GROUPÉE DE SÉCURITÉ
Audio/video, information and communication technology equipment –
Part 3: Safety aspects for DC power transfer through communication cables and
ports
Équipements des technologies de l’audio/vidéo, de l’information et de la
communication –

Partie 3: Aspects liés à la sécurité relatifs au transfert de puissance en courant

continu au moyen de câbles et d’accès de communication
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 33.160.01; 35.020 ISBN 978-2-8322-5131-7

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 62368-3:2017 © IEC 2017
CONTENTS

FOREWORD ........................................................................................................................... 4

1 Scope .............................................................................................................................. 6

2 Normative references ...................................................................................................... 6

3 Terms, definitions and abbreviated terms ........................................................................ 7

3.1 Terms and definitions .............................................................................................. 7

3.2 Abbreviated terms ................................................................................................... 8

4 General requirements ...................................................................................................... 9

5 Power transfer using ES1 or ES2 voltages ....................................................................... 9

5.1 General requirements ............................................................................................. 9

5.2 Electrical-caused injury, electrical sources and safeguards ..................................... 9

5.3 Electrical-caused fire, power sources and safeguards ............................................. 9

5.3.1 DC power transfer interconnection to building wiring ........................................ 9

5.3.2 DC power transfer interconnection to other equipment ................................... 10

5.4 Safeguards to protect against a single fault condition in the PSE .......................... 10

5.4.1 Requirement for the PSE ............................................................................... 10

5.4.2 Requirement for the PD ................................................................................. 11

6 Power transfer using RFT .............................................................................................. 11

6.1 General requirements ........................................................................................... 11

6.2 Connection to ICT networks .................................................................................. 11

6.3 Electrically caused injury ...................................................................................... 11

6.3.1 Classification and limits of electrical energy sources ..................................... 11

6.3.2 Accessibility to electrical energy sources and safeguards .............................. 14

6.3.3 Safeguards .................................................................................................... 15

6.3.4 Installation instructions .................................................................................. 16

6.4 Electrically caused fire .......................................................................................... 17

6.4.1 Classification of RFT power sources .............................................................. 17

6.4.2 Fire protection requirements .......................................................................... 17

Annex A (informative) Remote power feeding ...................................................................... 19

A.1 Overview............................................................................................................... 19

A.2 Operational considerations ................................................................................... 19

A.3 Safety considerations ............................................................................................ 20

A.4 Principle of remote power feeding ......................................................................... 20

A.4.1 RFT-C circuits ............................................................................................... 20

A.4.2 RFT-V circuits ................................................................................................ 22

A.5 Safety aspects ...................................................................................................... 22

A.5.1 Steady-state body current .............................................................................. 22

A.5.2 Body resistance ............................................................................................. 23

A.5.3 Charged capacitance ..................................................................................... 23

Annex B (informative) Rationale for 5.4 ................................................................................ 24

Bibliography .......................................................................................................................... 25

Figure 1 – Maximum current after a single fault..................................................................... 12

Figure 2 – Maximum voltages permitted after a single fault ................................................... 14

Figure 3 – Limits for capacitance values of RFT circuits of the total system .......................... 17

Figure A.1 – Example of a remote power feeding RFT-C system .......................................... 21

---------------------- Page: 4 ----------------------
IEC 62368-3:2017 © IEC 2017 – 3 –

Figure A.2 – Example of a remote power feeding RFT-C system with repeater ..................... 21

Figure A.3 – Example of a remote power feeding RFT-V system ........................................... 22

Table 1 – RFT-V circuits, power and current limitations ........................................................ 18

---------------------- Page: 5 ----------------------
– 4 – IEC 62368-3:2017 © IEC 2017
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
AUDIO/VIDEO, INFORMATION AND COMMUNICATION
TECHNOLOGY EQUIPMENT –
Part 3: Safety aspects for DC power transfer
through communication cables and ports
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 62368-3 has been prepared by IEC technical committee 108:

Safety of electronic equipment within the field of audio/video, information technology and

communication technology.
The text of this International Standard is based on the following documents:
FDIS Report on voting
108/695/FDIS 108/696/RVD

Full information on the voting for the approval of this International Standard can be found in

the report on voting indicated in the above table.

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

---------------------- Page: 6 ----------------------
IEC 62368-3:2017 © IEC 2017 – 5 –
This International Standard is to be used in conjunction with IEC 62368-1:2014.

It has the status of a group safety publication in accordance with IEC Guide 104.

The subclauses of IEC 62368-1 apply as far as reasonable. Where safety aspects are similar

to those of IEC 62368-1, the relevant clause or subclause of IEC 62368-1 is given for

reference in a note in the relevant subclause. Where a requirement in IEC 62368-3 refers to a

requirement or criterion of IEC 62368-1, a specific reference to IEC 62368-1 is made.

In this standard, the following print types are used:
– requirements proper and normative annexes: in roman type;
– compliance statements and test specifications: in italic type;
– notes and other informative matter: in smaller roman type;
– normative conditions within tables: in smaller roman type;
– terms that are defined in Clause 3 and in IEC 62368-1:2014: in bold type.

The following differing practices of a less permanent nature exist in the countries indicated

below.
– 6.1: other requirements apply regarding power transfer using RFT (US);

– 6.3.3.1: regarding separation from other circuits and parts, see note in 4.1.15 of

IEC 62368-1:2014 (Norway);
– A.1: RFT-V systems and requirements (North America).

A list of all parts in the IEC 62368 series, published under the general title Audio/video,

information and communication technology equipment, can be found on the IEC website.

The committee has decided that the contents of this document will remain unchanged until the

stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to

the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
---------------------- Page: 7 ----------------------
– 6 – IEC 62368-3:2017 © IEC 2017
AUDIO/VIDEO, INFORMATION AND COMMUNICATION
TECHNOLOGY EQUIPMENT –
Part 3: Safety aspects for DC power transfer
through communication cables and ports
1 Scope

This part of IEC 62368 applies to equipment intended to supply and receive operating power

through communication cables or ports. It covers particular requirements for circuits that are

designed to transfer DC power from a power sourcing equipment (PSE) to a powered
device (PD).

The power transfer uses voltages at ES1 or ES2 or in very specific cases voltage levels at

ES3.

NOTE 1 ES1 can generally be assumed to have similar limits as non-hazardous voltage definitions used in other

standards (for example, SELV, PELV).

NOTE 2 ES2 can generally be assumed to have similar limits for single fault conditions as non-hazardous

voltage definitions used in other standards.

NOTE 3 PS2 circuits are generally expected to provide less than 100 W to an undefined load under both normal

operating conditions and single fault conditions.
EXAMPLES
– For power transfer using voltages at ES1: USB, PoE, ISDN S0, etc.

– For power transfer using voltages at ES2: analogue telephone during ringing, ISDN U, etc.

– For power transfer using voltages at ES3: power feeding used by communications service providers and

utilities communication circuits (for example, RFT circuits, such as line powered HDSLx, SHDSLx, VDSLx

and G.fast).

NOTE 4 Any cable provided with a connector defined by an industry standard that permits DC power transfer

between equipment is considered a communication cable even if communication does not take place. For example,

a USB cable can be used just to recharge a portable device battery.

This group safety publication is primarily intended to be used as a product safety standard for

the products mentioned in the scope, but shall also be used by technical committees in the

preparation of standards for products similar to those mentioned in the scope of this standard,

in accordance with the principles laid down in IEC Guide 104 and lSO/lEC Guide 51.

One of the responsibilities of a technical committee is, wherever applicable, to make use of

basic safety publications and/or group safety publications in the preparation of its publications.

2 Normative references

The following documents are referred to in the text in such a way that some or all of their

content constitutes requirements of this document. For dated references, only the edition

cited applies. For undated references, the latest edition of the referenced document (including

any amendments) applies.

IEC 62368-1:2014, Audio/video, information and communication technology equipment –

Part 1: Safety requirements

IEC Guide 104, The preparation of safety publications and the use of basic safety publications

and group safety publications
---------------------- Page: 8 ----------------------
IEC 62368-3:2017 © IEC 2017 – 7 –
lSO/lEC Guide 51, Safety aspects – Guidelines for their inclusion in standards
3 Terms, definitions and abbreviated terms
3.1 Terms and definitions

For the purposes of this document, the terms and definitions given in IEC 62368-1:2014 and

the following apply.

ISO and IEC maintain terminological databases for use in standardization at the following

addresses:
– IEC Electropedia: available at http://www.electropedia.org/
– ISO Online browsing platform: available at http://www.iso.org/obp
3.1.1
power sourcing equipment
PSE

equipment, other than dedicated external power supply units intended to supply specific

equipment within the scope of IEC 62368-1, supplying DC power to other equipment through

communication cables or ports

Note 1 to entry: It should be noted that the IEEE 802.3-2015 standard has a similar but different definition.

Note 2 to entry: This note applies to the French language only.
3.1.2
powered device
equipment supplied DC power by a PSE through communication cables or ports

Note 1 to entry: It should be noted that the IEEE 802.3-2015 standard has a similar but different definition.

Note 2 to entry: Some in line devices may just function as a PSE to inject power into the cable connecting to PD

equipment. IEEE 802.3-2015 identifies such devices as Midspan PSE.

Note 3 to entry: Some PD equipment may also have a PSE output to pass on unused power to other PD

equipment.
Note 4 to entry: This note applies to the French language only.
3.1.3
information and communication technology network
ICT network
metallically terminated transmission medium and its associated equipment and
communication cables

Note 1 to entry: The cable consists of two or more conductors intended for communication and/or power transfer

between the various pieces of equipment. The equipment may be located within the same or separate structures,

buildings or locations, excluding:

– the mains system for supply, transmission and distribution of electrical power, if used as a communication

transmission medium;
– a dedicated HBES/BACS network.

Note 2 to entry: This may include twisted pairs, and may include circuits, that are subjected to transients as

indicated by ID1 in Table 14 of IEC 62368-1:2014 (assumed to be 1,5 kV).
Note 3 to entry: An ICT network may be:
– publicly or privately owned;

– subject to longitudinal (common mode) voltages induced from nearby power lines or electric traction lines.

Note 4 to entry: Examples of ICT networks are:
---------------------- Page: 9 ----------------------
– 8 – IEC 62368-3:2017 © IEC 2017
– a public switched telephone network;
– a public data network;
– an Integrated Services Digital Network (ISDN);

– a private network with electrical interface characteristics similar to the above.

Note 5 to entry: For information about circuit voltages and signals which may be present, see Annex B of

IEC 62949:2017.
Note 6 to entry: This note applies to the French language only.
3.1.4
RFT circuit
remote feeding telecommunication circuit
remote feeding communication circuit

equipment circuit within the ICT network not connected to an AC mains, intended to supply

or receive DC power at voltages exceeding the limits of ES2, and on which overvoltages may

occur

Note 1 to entry: Communication signalling is not required to be present on an RFT circuit.

Note 2 to entry: This note applies to the French language only.
3.1.5
RFT-C circuit

RFT circuit which is so designed and protected that under normal operating conditions and

single fault conditions, the currents in the circuit do not exceed defined values

Note 1 to entry: The limit values of current under normal operating conditions and single fault conditions are

specified in 6.3.1.1.
3.1.6
RFT-V circuit

RFT circuit which is so designed and protected that under normal operating conditions and

single fault conditions, the voltages are limited and the accessible area of contact is limited

Note 1 to entry: The limit values of voltage under normal operating conditions and single fault conditions are

specified in 6.3.1.2.
3.2 Abbreviated terms
BACS building automation and control system
HBES home and building electronic system
HDSL high bit-rate digital subscriber line
ICT information and communication technology
ISDN integrated services digital network
LPS limited power source
PD powered device
PoE power over ethernet
PSE power sourcing equipment
RFT remote feeding (tele)communication
SHDSL symmetric high bit-rate digital subscriber line
USB universal serial bus
VDSL very-high-bit-rate digital subscriber line
---------------------- Page: 10 ----------------------
IEC 62368-3:2017 © IEC 2017 – 9 –
4 General requirements

For equipment serving as a PD or a PSE using voltages at ES1 or ES2, the requirements of

Clause 5 apply. However, Clause 5 does not apply to equipment used as PSE or PD with

proprietary connectors or where a proprietary protocol is used to enable the power transfer.

NOTE A proprietary connector is a connector not used in an industry standard and which is under the control of

one manufacturer.

For equipment serving as a PD or a PSE using RFT, the requirements of Clause 6 apply.

5 Power transfer using ES1 or ES2 voltages
5.1 General requirements

The maximum rated output voltage of the PSE under normal operating conditions shall not

exceed the rated limits of the intended communication systems power source functional

specifications under conditions of no load, normal load, and maximum rated load.

NOTE 1 For USB 2.0 and 3.1, the limits are 5,25 V. For a USB battery charger, the limit is 6 V. USB power

delivery can be rated up to 20 V max.
NOTE 2 Other ES1 and ES2 DC power transfer systems are under investigation.

Where a PD or PSE have the capability to both provide power and receive power, all the

requirements from 5.1 to 5.4 shall apply for each mode as applicable.

NOTE 3 Equipment can have multiple ports serving different PSE and PD roles simultaneously in any combination.

5.2 Electrical-caused injury, electrical sources and safeguards

The requirements of Clause 5 of IEC 62368-1:2014 apply for a PSE classified as ES1 and

ES2.
5.3 Electrical-caused fire, power sources and safeguards
5.3.1 DC power transfer interconnection to building wiring

To protect the communication cables, including building wiring, and other devices including

the PD, the PSE shall implement power limiting control to reduce the likelihood of ignition and

shall limit the output current to a value that does not cause damage to the wiring system.

To reduce the likelihood of ignition, the PSE circuit that provides power shall comply with the

requirements for a limited power source (LPS) of Clause Q.1 of IEC 62368 1:2014.

NOTE 1 This means that a fire enclosure is not normally required in the power feeding load circuits of the PD.

For interconnection of PSE circuits to other devices for DC power transfer via building wiring,

where it is unknown whether remotely attached devices comply with this document, the PSE

shall limit the output current to a value that does not cause damage to the wiring system due

to overheating, under any conditions of external load up to and including short circuits. The

maximum continuous current from the equipment shall not exceed a current limit that is

suitable for the minimum wire gauge specified in the equipment installation instructions.

For a PD that receives multiple power input circuits from one or more PSE, the PD also shall

implement power limiting in accordance with PS2 or Annex Q of IEC 62368-1:2014 to control

additive power from returning to another PSE under normal operating conditions, abnormal

operating conditions and single fault conditions.

NOTE 2 The requirement for single fault condition does not apply to an IC current limiter in compliance with

Clause G.9 of IEC 62368-1:2014.
---------------------- Page: 11 ----------------------
– 10 – IEC 62368-3:2017 © IEC 2017

EXAMPLES of such PD equipment are: an analogue telephone, a security camera, a network swi

...

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