IEC TR 62652:2010

Effects of engaging and separating under electrical load on connector interfaces in cabling used to support IEEE 802.3af (power-over-ethernet) applications

IEC/TR 62652:2010(E) is intended to provide information on the effects of engaging and separating under electrical load on the connector interfaces in cabling, used to support IEEE 802.3af (Power-over-Ethernet (PoE)) applications.

General Information

• Status: Published
• Publication Date: 29-Mar-2010
• ICS: 31.220.10 - Plug-and-socket devices. Connectors
• Technical Committee: SC 48B - Electrical connectors
• Current Stage: PPUB - Publication issued
• Start Date: 30-Mar-2010
• Completion Date: 30-Jun-2010

Standards Content (Sample)

IEC/TR 62652 ®
Edition 1.0 2010-03
TECHNICAL
REPORT
colour
inside
Effects of engaging and separating under electrical load on connector interfaces
in cabling used to support IEEE 802.3af (power-over-ethernet) applications

IEC/TR 62652:2010(E)
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IEC/TR 62652 ®
Edition 1.0 2010-03
TECHNICAL
REPORT
colour
inside
Effects of engaging and separating under electrical load on connector interfaces
in cabling used to support IEEE 802.3af (power-over-ethernet) applications

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
PRICE CODE
U
ICS 31.220.10 ISBN 2-8318-1087-3
– 2 – TR 62652 © IEC:2010(E)
CONTENTS
FOREWORD.4
INTRODUCTION.6
1 Scope.7
2 Normative references .7
3 Abbreviations .7
4 General .8
5 Telecommunications industry information .8
6 Technical information .9
6.1 Electrical discharges .9
6.2 Surface plating. long and short term effects.10
6.3 IEEE 802.3af – Power-over-Ethernet environment (PoE) .11
6.4 Factors affecting the connector durability and definition of a nominal contact
zone.12
6.5 Acceptance criteria.13
7 Test procedures, test set-up description and results .14
7.1 General .14
7.2 Tests 1A and 2A – Evaluation of the mechanical damage.15
7.3 Tests 3A.15
7.4 Test 4A – Comparison of different IEC 60603-7 connectors.17
7.4.1 General .17
7.4.2 Tests – Visual inspection of contacts .17
7.4.3 Results and observations to test 4A.17
7.5 Test 5A – Resistive test setup simulating PoE power stress .19
7.5.1 General .19
7.5.2 Test setup .19
7.5.3 Tests – Visal inspection of contacts.19
7.5.4 Results and observations to test 5A.19
7.6 Test 6A – Engaging and separating with IEEE 802.3af hardware.20
7.6.1 PoE hardware.20
7.6.2 Tests – Visual inspection of contacts .21
7.6.3 Results – Test 6A .21
7.7 Test 7A and 8A – Effect of speed of contact separation.22
7.8 Tests 9A, 10A and 11A – Effect of the cord length.22
7.9 Test 12A – Effect of polarity .23
7.10 Test 13 A – Investigation of IEC 60603-7-7 or IEC 61076-3-110 connecting
hardware .24
7.11 Tests 14A and 15 A. 100 m long cable test.25
8 Conclusions.26
9 Future work .26
Bibliography.28

Figure 1 – Illustration of a typical shielded 8-way connector according IEC 60603-7 .9
Figure 2 – Illustration of an IEC 60603-7-7 or IEC 61076-3-110 connector.9
Figure 3 – Connecting hardware contacts .10
Figure 4 – Endspan PSE – Alternative A according to IEEE 802.3af .11

TR 62652 © IEC:2010(E) – 3 –
Figure 5 – Midspan PSE – Alternative B according to IEEE 802.3af .11
Figure 6 – Cables used in the study.12
Figure 7 – Illustration of contact engaging cycle.13
Figure 8 – Illustration of a nominal contact area concept.13
Figure 9 – Illustration of a low level contact resistance (bulk) test .14
Figure 10 – IEC 60603-7-7 connector contacts .15
Figure 11 – Test circuit A.16
Figure 12 – Test results of tests 1A and 3A.16
Figure 13 – Test circuit B.17
Figure 14 – Damage due to electrical discharges.18
Figure 15 – Test 4A – Changes in LLCR .18
Figure 16 – Test circuit C.19
Figure 17 – Test 5A observations .20
Figure 18 – Test 5A results show little change in LLCR.20
Figure 19 – Test circuit D.21
Figure 20 – Test results test 6A .21
Figure 21 – Test circuit E.22
Figure 22 – LLCR (bulk) change .22
Figure 23 – Test circuit F .23
Figure 24 – Test 12A – Observed minor damage to the plug connector surface .24
Figure 25 – Discharge effects for the IEC 60603-7-7 connector .25
Figure 26 – Test results test 13A .25
Figure 27 – Change in the LLCR due to electrical and mechanical discharge for
IEC 60603-7 connectors including 2 m, 10 m, and 100 m cables combined.26

Table 1 – Some factors affecting the connecting hardware durability .12
Table 2 – Selected parameters of the test set up and procedures .14

– 4 – TR 62652 © IEC:2010(E)
INTERNATIONAL ELECTROTECHNICAL COMMISSION
___________
EFFECTS OF ENGAGING AND SEPARATING UNDER ELECTRICAL LOAD
ON CONNECTOR INTERFACES IN CABLING USED TO SUPPORT
IEEE 802.3af (POWER-OVER-ETHERNET) APPLICATIONS

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
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Technical Report IEC 62652 has been prepared by subcommittee 48B: Connectors, of IEC
technical committee 48: Electromechanical components and mechanical structures for
electronic equipment.
This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

TR 62652 © IEC:2010(E) – 5 –
The text of this standard is based on the following documents:
DTR Report on voting
48B/2076/DTR 48B/2146/RVC
The committee has decided that the contents of this publication will remain unchanged until
the stability date indicated on the IEC web site under "http://webstore.iec.ch" in the data
related to the specific publication. At this date, the publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
A bilingual version of this publication may be issued at a later date.

IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct
understanding of its contents. Users should therefore print this document using a
colour printer.
– 6 – TR 62652 © IEC:2010(E)
INTRODUCTION
The ISO/IEC/JTC1/SC25 subcommittee requested IEC SC 48B to prepare an engaging and
separating under electrical load test method to be referenced in their standards. This test
method standard was published as IEC 60512-9-3:2006. The experts of SC 48B/WG5 were
concerned about the effect of engaging/separating under electrical load on the IEC 60603-7
series connector interfaces that would be typically used in the IEEE 802.3af (PoE)
applications. The experts developed a set of tests to evaluate the effects, the results of which
are reported in this Technical Report.
NOTE “Engaging” and “Separating” are terms used in most IEC TC 48 publications to describe the physical
mating or un-mating of connectors.
IEC 60050-581:1978, 581-08-08 defines the terms as follows:
engaging and separating force
connector mating and unmating force (deprecated)
The force required to engage fully or separate a pair of mating components including the effect of a coupling,
locking or similar device.
The IEC 60603-7 series of standards use the terms mating and un-mating throughout. To avoid confusion in
reading this Technical Report and also the IEC 60603-7 series of standards, it is important to know that the term
“engaging” is equivalent to “mating” and the term “separating” is equivalent to “un-mating”.

—————————
IEC 60050-581:1978, International Electrotechnical Vocabulary – Chapter 581: Electromechanical components
for electronic equipment
TR 62652 © IEC:2010(E) – 7 –
EFFECTS OF ENGAGING AND SEPARATING UNDER ELECTRICAL LOAD
ON CONNECTOR INTERFACES IN CABLING USED TO SUPPORT
IEEE 802.3af (POWER-OVER-ETHERNET) APPLICATIONS

1 Scope
This Technical Report is intended to provide information on the effects of engaging and
separating under electrical load on the connector interfaces in cabling, used to support
IEEE 802.3af (Power-over-Ethernet (PoE)) applications.
2 Normative references
The following referenced documents are indispensable for the application 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 60512-9-3:2006, Connectors for electronic equipment – Tests and measurements – Part
9-3: Endurance tests – Test 9c: Mechanical operation (engaging/separating) with electrical
load
IEC 60603-7, Connectors for electronic equipment – Part 7: Detail specification for 8-way,
unshielded, free and fixed connectors
IEC 60603-7-7, Connectors for electronic equipment – Part 7-7: Detail specification for 8-
way, shielded, free and fixed connectors, for data transmissions with frequencies up to
600 MHz
IEC 61076-3-110, Connectors for electronic equipment – Product requirements – Part 3-110:
Detail specification for shielded, free and fixed connectors for data transmission with
frequencies up to 1 000 MHz
IEC 61156 (all parts), Multicore and symmetrical pair/quad cables for digital communications
ISO/IEC 11801:2002, Information technology – Generic cabling for customer premises
Amendment 1 (2008)
IEEE 802.3af, "Carrier Sense Multiple Access with Collision Detection (CSMA/CD) Access
Method and Physical Layer Specifications – Data Terminal Equipment (DTE) Power Via Media
Dependent Interface (MDI),"
3 Abbreviations
For the purposes of this document the following abbreviations and special terms apply.
IEEE The Institute of Electrical and Electronics Engineers
LLCR Low-Level Contact Resistance
S/FTP Acronym for a twisted pair cable with overall braid screened cable with foil screened
balanced elements
U/UTP Acronym for a twisted pair cable with no overall screen and unscreened balanced
elements
– 8 – TR 62652 © IEC:2010(E)
4 General
This Technical Report summarizes information on the effects of engaging and separating
under electrical load on the connecting hardware in cabling used to support IEEE 802.3af
(Power-over-Ethernet (PoE)) applications. It is intended to make the industry aware of
possible problems utilizing modular connectors in applications with increasing power levels
and to encourage further investigation of the effects of the connector engaging under
electrical load.
This report also includes information regarding test procedures and test results. It is not the
intention of this report to recommend any test procedure or specify requirements (to be
utilized in order to evaluate the connecting hardware) for connectors in cabling used to
support IEEE 802.3af applications.
The tests were conducted using fixed and free connectors made by US, European and Asian-
Pacific suppliers. The evaluation utilized several test procedures and took place at test
facilities located in the USA and Switzerland. The bulk low level contact resistance was used
as a criterion in measuring the effects of engaging cycles under the electrical load on
connector durability. In some cases the electrical load was applied for the separating cycles
only, in other cases the electrical load was used in both engaging and separating. The
electrical load power exceeded the corresponding requirements of the IEEE 802.3af standard.
5 Telecommunications industry information
With the advent of generic cabling used in the telecommunication industry, connectors are
now used for a multitude of applications. In the past the great majority of such applications all
were of a low power level: 4 W or less.
The development of the IEEE 802.3af (Power over Ethernet (PoE)) standard changed the
situation. This application requires transmitting power of up to 15 W over the connectors with
a nominal voltage of 48 V . And already new IEEE projects are under way to increase the
dc
transmitted power level up to 40 W.
Different telecommunication connectors subject to the ISO/IEC standards can be used in
IEEE 802.3af applications. Some of the connectors used in this study are illustrated in
Figures 1 and 2. Figure 1 shows a connector according to IEC 60603-7 which is typically used
for applications up to 500 MHz. Figure 2 illustrates a connector according to IEC 60603-7-7 or
IEC 61076-3-110 which is typically used for applications up to 1 000 MHz.
While transmitting some power over engaged connectors is within the specification for
continuous current, the problem starts when the plug is removed / disconnected under
electrical load. The breaking of a live contact produces discharges that may damage the
surfaces on the connector contacts.
Different factors that could affect the connector interfaces were evaluated, including: power
levels from 10 W to 20 W, cable length from 2 m to 100 m, the electrical load polarity, and
speed of disconnect. The report includes observations based on the visual inspection prior
and after multiple engaging cycles and the temperature and humidity conditioning. The report
contains a proposal for additional future testing.

TR 62652 © IEC:2010(E) – 9 –
IEC  554/10
Figure 1 – Illustration of a typical shielded 8-way connector according IEC 60603-7

7× AH1
0,05 mm
C
0,002 in C
B1
0,05 mm
X
0,002 in X
AH1
AD1
0,15 maximum taper
1 8
B
CQ1
6 3 4 5
AB1
AH1
T1
0,25 mm C
0,010 in C W1
C
CS1
0,25 mm C
0,010 in C
S1
CT1
IEC  555/10
Figure 2 – Illustration of an IEC 60603-7-7 or IEC 61076-3-110 connector
6 Technical information
6.1 Electrical discharges
The process of connector engaging and separating causes mechanical damage to the surface
of the interface. Such damage could be accelerated or accentuated by the electrical potential
between a plug and jack if the electrical load is present during the engaging cycle. In general,
there are two such phenomena: corona discharge and spark discharge.
The corona discharge is caused by ionized gas in the presence of an electrical field with a
high potential gradient. It is a time-dependent process, which may cause erosion, pitted
surface and multiple but shallow craters. There are two distinct types of corona – positive and
CA1
CK1
CN
CP1
K1
– 10 – TR 62652 © IEC:2010(E)
negative. For IEC 60603-7 type connectors in a IEEE 802.3af environment corona discharge
may not be relevant, since there are no long term, high potential gradients present.
Another type of discharge is spark. The spark discharge is to be considered a single and
irregular event. Due its high speed it is considered for this work to be time-independent. The
damage caused by a spark is usually limited to a singe crater. However, it is not possible to
differentiate with certainty if a particular crater was caused by corona or spark.
The effects of the discharges are accompanied by changes in the interface appearance
caused by mechanical operations. Connecting hardware contacts are shown in Figure 3.

A B C D
IEC  556/10
Key
A Fresh unused
B Mechanical operations without electrical load
C Crater caused by a spark
D Multiple craters
Figure 3 – Connecting hardware contacts
6.2 Surface plating. long and short term effects
The connector contacts made of copper alloys are prote
...