IEC TR 62652 pdf download – 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 pdf download – 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 andseparating under electrical load on the connector interfaces in cabling,used to supportIEEE 802.3af (Power-over-Ethernet (PoE)) applications.
2Normative 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 editionof the referenced document (including any amendments) applies.
IEC 60512-9-3:2006,Connectors for electronic equipment – Tests and measurements – Part9-3: Endurance tests – Test 9c: Mechanical operation (engaging/separating) with electricalload
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 to600 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 withfrequencies up to 1 0o0 MHz
IEC 61156(all parts)，Multicore and symmetrical pair/lquad cables for digital communicationsISO/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) AccessMethod and Physical Layer Specifications – Data Terminal Equipment (DTE) Power Via MediaDependent Interface (MmDI),”
Abbreviations
For the purposes of this document the following abbreviations and special terms apply.IEEEThe Institute of Electrical and Electronics Engineers
LLCRLow-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 balancedelements
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 1 5 W over the connectors with a nominal voltage of 48 V dc . And already new IEEE projects are under way to increase the 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 61 076-3-1 1 0 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.