1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationMulticore and symmetricalpair/quad cables for digital communicationsPart 1-4: Symmetrical pair/quad cables with transmission characteristics up to 1 000 MHz Conductor heating of
2、bundled data grade cables for limited power transmission based on IEEE 802.3DD IEC/PAS 61156-1-4:2010National forewordThis Draft for Development is the UK implementation of IEC/PAS 61156-1-4:2010.The UK participation in its preparation was entrusted to Technical CommitteeEPL/46, Cables, wires and wa
3、veguides, radio frequency connectors and accessories for communication and signalling.A list of organizations represented on this committee can be obtained onrequest to its secretary.This publication does not purport to include all the necessary provisions of acontract. Users are responsible for its
4、 correct application. BSI 2010ISBN 978 0 580 70798 8ICS 33.120.20Compliance with a British Standard cannot confer immunity fromlegal obligations.This Draft for Development was published under the authority of theStandards Policy and Strategy Committee on 30 September 2010.Amendments issued since pub
5、licationAmd. No. Date Text affectedDRAFT FOR DEVELOPMENTDD IEC/PAS 61156-1-4:2010IEC/PAS 61156-1-4Edition 1.0 2010-06PUBLICLY AVAILABLE SPECIFICATIONPRE-STANDARD Multicore and symmetrical pair/quad cables for digital communications Part 1-4: Symmetrical pair/quad cables with transmission characteris
6、tics up to 1 000 MHz Conductor heating of bundled data grade cables for limited power transmission based on IEEE 802.3 INTERNATIONAL ELECTROTECHNICAL COMMISSION XICS 33.120.20 PRICE CODEISBN 978-2-88912-032-1 Registered trademark of the International Electrotechnical Commission colourinside 2 PAS 61
7、156-1-4 IEC:2010(E) CONTENTS FOREWORD.4 1 Scope.6 2 Normative references8 3 Terms, definitions, symbols, units and abbreviated terms 8 3.1 Terms and definitions 8 3.2 Symbols, units and abbreviated terms9 4 The testing of bundled cables .11 4.1 General comments 11 4.2 The bundling of cables.11 4.3 T
8、he suspension of the cable bundle .14 4.4 Assessment of the concatenated loop resistance of all pairs 16 5 The temperature as a function of the current load in conductors of bundled cables in hexagonal densest packing structure17 5.1 The test description .17 5.2 The temperature measurement 18 5.3 Th
9、e heat generation and the resulting increase of the resistance20 5.4 The specific resistivity referencing the IACS.24 6 Assessing already deployed cable systems .26 6.1 Background .26 6.2 The installed base .26 6.3 A simplified assessment of the installed base.27 7 The higher performing data grade c
10、ables 27 7.1 Conductor and cable diameters27 8 The heat dissipation on heated and bundled cables.28 8.1 Radiation.28 8.2 Conduction 28 8.3 Convection 28 9 The heat dissipation in a heated conductor, pair or cable which has to be taken into account29 9.1 The heat dissipation of individual components2
11、9 9.2 The heat dissipation of real cables.35 10 Thermodynamic considerations for a combined experimental and mathematical solution of the heating problem .37 10.1 Objective .37 10.2 The cable bundle considered as a layered structure .37 10.3 The heat transfer through the layered structure39 10.4 The
12、 heat transfer through the bundle in layered structure with internal heat generation .40 Figure 1 Lay-plate arrangement for stringing up and fixing the cables to maintain the densest hexagonal packing structure, here shown for a 61-cable bundle13 Figure 2 Arrangement of cardboardmaskplates over the
13、ends of the cable bundle to apply the insulating foam over the ends of the bundle13 Figure 3 Schematic of the suspension of the cable bundle 15 DD IEC/PAS 61156-1-4:2010PAS 61156-1-4 IEC:2010(E) 3 Figure 4 Cross-section of a cable bundle used for the test, here a bundle of 61 cables.17 Figure 5 Conn
14、ections on both ends of the center cable to obtain two nearly identical “pair” resistances, which can then be measured using the voltage across these pairs19 Figure 6 View of part of the cable bundle around the measurement cables indicating the “temperature” measurement leads and those for the conca
15、tenation between the cable layers in the bundle (here for n = 0 4)19 Figure 7 Schematic for connecting the cables in the different layers for alternatively 2- and 4-pair heating22 Figure 8 Heat dissipation of a freely suspended conductor29 Figure 9 Heat dissipation of a single insulated conductor 30
16、 Figure 10 Dissipation of an unscreened twisted pair exposed to current heating31 Figure 11 Dissipation of a screened twisted pair exposed to current heating .32 Figure 12 Heat dissipation in an unscreened cable .33 Figure 13 Heat dissipation of an overall screened cable34 Figure 14 Heat dissipation
17、 in an individually screened pair cable with overall braid or drain-wire with an overall metal / polymeric composite tape .34 Figure 15 A data grade cable of arbitrary design.36 Figure 16 Bundled cables indicating the air spaces between the cables 38 Figure 17 The thermodynamic equivalent layered st
18、ructure of the cables and air gaps .38 DD IEC/PAS 61156-1-4:2010 4 PAS 61156-1-4 IEC:2010(E) INTERNATIONAL ELECTROTECHNICAL COMMISSION _ MULTICORE AND SYMMETRICAL PAIR/QUAD CABLES FOR DIGITAL COMMUNICATIONS Part 1-4: Symmetrical pair/quad cables with transmission characteristics up to 1 000 MHz Cond
19、uctor heating of bundled data grade cables for limited power transmission based on IEEE 802.3 FOREWORD 1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising all national electrotechnical committees (IEC National Committees). The object of I
20、EC 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
21、) 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
22、 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 nea
23、rly 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 tha
24、t 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 Committee
25、s 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 a
26、ny 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 e
27、dition 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
28、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 indisp
29、ensable 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. A PAS is a technical specification
30、 not fulfilling the requirements for a standard, but made available to the public. IEC-PAS 61156-1-4 has been processed by subcommittee 46C: Wires and symmetric cables, of IEC technical committee 46: Cables, wires, waveguides, R.F. connectors, R.F. and microwave passive components and accessories. T
31、he text of this PAS is based on the following document: This PAS was approved for publication by the P-members of the committee concerned as indicated in the following document Draft PAS Report on voting 46C/912/PAS 46C/918/RVD DD IEC/PAS 61156-1-4:2010PAS 61156-1-4 IEC:2010(E) 5 Following publicati
32、on of this PAS, which is a pre-standard publication, the technical committee or subcommittee concerned may transform it into an International Standard. This PAS shall remain valid for an initial maximum period of 3 years starting from the publication date. The validity may be extended for a single p
33、eriod up to a maximum of 3 years, at the end of which it shall be published as another type of normative document, or shall be withdrawn. A list of all parts of the IEC 61156 series, under the general title: Multicore and symmetrical pair/quad cables for digital communications, can be found on the I
34、EC website. 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. DD IEC/PAS 61156-1-4:2010 6 PAS 61156-1-4 IE
35、C:2010(E) MULTICORE AND SYMMETRICAL PAIR/QUAD CABLES FOR DIGITAL COMMUNICATIONS Part 1-4: Symmetrical pair/quad cables with transmission characteristics up to 1 000 MHz Conductor heating of bundled data grade cables for limited power transmission based on IEEE 802.3 1 Scope This PAS is a technical s
36、upplement to IEC 61156-1, edition 3 (2007): Multicore and symmetrical pair/quad cables for digital communications Part 1: Generic specification. This PAS, covering exclusively four-pair data grade cables, is intended to provide a test method for the determination of the maximum attained conductor te
37、mperatures which occur due to the deployment of the IEEE protocol for PoE /PoEP. It gives as well the required background information about the thermodynamic behaviour of such bundled cables, if they are located in areas with restricted heat dissipation, a reality which occurs in every installation
38、situation. However, only the basic principles are given, as the rigorous application and solution of these problems fall into the relevant cabling standards. NOTE 1 The restriction to four-pair data grade cables is very important, as the heating of a multiple pair cable, especially if it has a prote
39、ctive screen, is much worse, since the ratio of the heat generation within the cross-section versus the overall circumferential surface to dissipate the heat is dramatically decreased, thus yielding substantially higher conductor temperatures. Additionally, the screen acts as a near perfect IRreflec
40、tor, thus increasing additionally only the excess heat within the cable. This restriction is of importance considering the installed base, where individual four-pair cables in a loose bundle arrangement may need to replace multiple pair cables. Hence, the main objective is a) the indication of a sui
41、table measuring method to assess the heating gradient across bundled data grade cables subject to d.c. power transmission, using for the incident and return conductors the common mode circuits of either two or four pairs; b) to provide, toward this end, the worst case assessment of the conductor and
42、 cable heating in bundled cable configurations, where the densest hexagonal packing configuration is required. This assessment of the heating is anticipated to be carried out under the extremely lenient condition of freely suspended cable bundles in an air-conditioned environment free of any air dra
43、ft, the heat dissipation thus being achieved by undisturbed convection into the surrounding environment; c) to provide some explanatory background information on the heat dissipation of heated conductors, insulated conductors, pair and cables, both screened or unscreened; d) to provide means to asse
44、ss the installed base of data grade cables with a view to their compliance with the requirements of either PoE or PoEP, if required in a comparative way, but based on the resistance assessment of at least one short cable length withdrawn from the installed base by replacement; e) to indicate the bas
45、ic physical assessment proceedure, based upon the testing of a cable bundle according to item b). A comparable heating trial on the same cable bundle, but under restricted heat dissipation conditions, yields then some indication of how to assess the maximum occurring temperatures under these conditi
46、ons; f) towards this end, the densest hexagonal packing configuration has to be simplified, using an equivalence in order to allow a consecutive evaluation of the heating under any heat dissipation restriction using a layered structure of the cables and the interstitial air spaces within the bundled
47、 structure. DD IEC/PAS 61156-1-4:2010PAS 61156-1-4 IEC:2010(E) 7 For this purpose a test method is provided: to allow the evaluation of the heating of the conductors of cable bundles where all (or a certain percentage of the cables) are exposed to powering. Additionally is considered the case that e
48、ither two of four pairs in a cable are used for d.c. power transmission; to measure the temperature of +=N1nn61 cables in hexagonal densest packing structure, in order to allow the assessment of the temperature gradient and the heat insulating properties of the cables. The densest packing of cables
49、represents the worst case situation 1; to provide a means to assess the performance potential of an installed base of data grade cables for power transmission. Evidently such a process has to take into account the specified d.c. resistance for categorized cables. If an experimental assessment of the installed cables is not feasible, then a normalizing procedure to IACS could be envisioned, though the specified cable d.c. resistances are substantially belo
