ISO/IEC TS 29125:2017/AMD1:2020

ISO/IEC TS 29125
Edition 1.0 2020-05
TECHNICAL
SPECIFICATION
AMENDMENT 1
Information technology – Telecommunications cabling requirements for remote
powering of terminal equipment

ISO/IEC TS 29125:2017-04/AMD1:2020-05(en)

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ISO/IEC TS 29125
Edition 1.0 2020-05
TECHNICAL
SPECIFICATION
AMENDMENT 1
Information technology – Telecommunications cabling requirements for remote

powering of terminal equipment

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 35.200 ISBN 978-2-8322-8310-3

– 2 – ISO/IEC TS 29125:2017/AMD1:2020
© ISO/IEC 2020
FOREWORD
This amendment has been prepared by subcommittee 25: Interconnection of information
technology equipment, of ISO/IEC joint technical committee 1: Information technology.
The text of this amendment is based on the following documents:
DTS Report on voting
JTC1-SC25/2919/DTS JTC1-SC25/2945/RVDTS

Full information on the voting for the approval of this amendment can be found in the report
on voting indicated in the above table.

_____________
INTRODUCTION to the amendment
This amendment incorporates changes necessary to include remote powering using single
pair cabling.
Introduction
Add the following at end of the last paragraph:
This document addresses the use of generic balanced single pair cabling for customer
premises, to be specified in future amendments of the ISO/IEC 11801 series, for remote
powering of terminal equipment. This document uses measurements and empirical models to
estimate the thermal performance of single pair cable bundles of various conductor diameters.
1 Scope
Replace list item a) with the following:
a) addresses the support of safety extra low voltage (SELV) and limited power source (LPS)
applications that provide remote power over:
• 4-pair balanced cabling in accordance with the reference implementations of
ISO/IEC 11801 series standards using currents per conductor of up to 500 mA;
• 1-pair balanced cabling using currents per conductor of up to 1 000 mA;
and targets the support of applications that provide remote power over balanced cabling to
terminal equipment,
5 Cabling selection and performance
Replace the first paragraph with the following:
Cabling for remote powering can be implemented using 4-pair and 1-pair balanced cabling.

© ISO/IEC 2020
6.3 Temperature rise and current capacity
Add the following new paragraph after the third paragraph:
The maximum current per conductor for different temperature rise in a bundle of 37 cables of
1-pair cables with 0,57 mm diameter conductors, and 37 cords of 1-pair 0,40 mm cords with
all pairs energized is shown in Table 5.
Replace the fourth paragraph with the following new paragraph:
Annex B provides an engineering model that may be used for specific cable types, cable
constructions, and installation conditions to derive the bundle size for a particular current per
conductor. Clause B.7 describes a simplified version of the engineering model in Annex B and
was used to derive the worst case values in Tables 1 to 9 based on constants calculated from
measurements of typical cables for each cable category or conductor diameter. The
measurement procedures used to determine the constants are detailed in Annex F.
Replace the Table 1 title with the following new title:
Table 1 – Maximum current per conductor versus temperature
rise in a 37 4-pair cable bundle in air and conduit
Add the following new Table 5 after Table 1:
Table 5 – Maximum current per conductor versus temperature rise
in a 37 1-pair cable bundle in air and conduit
Temperature rise Current per conductor 0,57 mm diameter Current per conductor 0,40 mm cords
°C mA mA
air conduit air conduit
5 866 738 608 518
7,5 1 061 904 744 634
10 1 225 1 044 860 732
12,5 1 370 1 167 961 819
15 1 501 1 278 1 053 897
17,5 1 621 1 381 1 137 969
20 1 733 1 476 1 216 1 036
Temperature rise above 10 °C shown in grey background is not recommended.
NOTE These values are based on conductor temperature measurement of typical cables and cords.

Replace the fifth paragraph with the following new paragraph:
Table 2 shows current capacity for different categories of 4-pair cable, independent of
construction, for a given temperature rise. Table 6 shows current capacity for 1-pair cables of
conductor diameters of cable, independent of construction, for a given temperature rise.

– 4 – ISO/IEC TS 29125:2017/AMD1:2020
© ISO/IEC 2020
Add the following new Table 6 after Table 2:
Table 6 – Calculated worst case current per conductor versus temperature
rise in a bundle of 37 1-pair cables of different conductor diameters in air and conduit
0,32 mm 0,40 mm 0,51 mm 0,57 mm 0,65 mm 0,81 mm 1,02 mm
diameter diameter diameter diameter diameter diameter diameter

ΔT mA mA mA mA mA mA mA
°C air conduit air conduit air conduit air conduit air conduit air conduit air conduit
2 307 262 384 327 490 417 548 466 624 532 779 663 981 835
4 435 370 543 463 693 590 775 660 883 753 1 101 938 1 387 1 181
6 533 454 666 567 849 723 949 808 1 082 922 1 349 1 149 1 699 1 446
8 615 524 769 655 981 835 1 096 933 1 249 1 065 1 558 1 327 1 962 1 670
10 688 586 860 732 1 096 934 1 225 1 044 1 397 1 190 1 742 1 484 2 194 1 867
12 753 642 942 802 1 201 1 023 1 342 1 143 1 530 1 304 1 908 1 625 2 403 2 046
14 814 693 1 017 867 1 297 1 105 1 450 1 235 1 653 1 409 2 061 1 755 2 596 2 210
16 870 741 1 087 926 1 387 1 181 1 550 1 320 1 767 1 506 2 203 1 877 2 775 2 362
18 923 786 1 153 983 1 471 1 253 1 644 1 400 1 874 1 597 2 337 1 991 2 943 2 506
20 973 829 1 216 1 036 1 551 1 321 1 733 1 476 1 976 1 684 2 463 2 098 3 102 2 641
Temperature rise above 10 °C shown in grey background is not recommended.
The values in this table are based on the implicit DC resistance derived from the insertion loss of the various
conductor diameters of cable. Manufacturers' and/or suppliers' specifications give information relating to a
specific cable.
NOTE The current per conductor for each 1-pair cable is also dependent on the cable construction.

6.4.3 Cable count within a bundle
Replace the first paragraph with the following new paragraphs:
This document uses 37-cable bundles as the basis for developing the temperature rise and
current per conductor with all pairs energized. For other cases (e.g. where bundle count
exceeds 37 cables), the guidelines provided in 6.4 can be used.
Refer to Table 3 to determine the maximum temperature rise using 500 mA per conductor for
4-pair cable bundles of different count.
Refer to Table 7 to determine the maximum temperature rise using 1 000 mA per conductor
for 1-pair cable bundles of different count.

© ISO/IEC 2020
Replace the Table 3 title with the following new title:
Table 3 – Temperature rise versus 4-pair cable bundle size (500 mA per conductor)
Add the following new Table 7 after Table 3:
Table 7 – Temperature rise versus 1-pair cable bundle size
(1 000 mA per conductor)
Temperature rise
°C
Number 0,32 mm 0,40 mm 0,51 mm 0,57 mm 0,65 mm 0,81 mm 1,02 mm
of cables diameter diameter diameter diameter diameter diameter diameter
mA mA mA mA mA mA mA
air conduit air conduit air conduit air conduit air conduit air conduit air conduit
1 2,9 4,4 1,9 2,8 1,1 1,7 0,9 1,4 0,7 1,1 0,5 0,7 0,3 0,4
7 8,2 11,9 5,2 7,6 3,2 4,7 2,6 3,8 2,0 2,9 1,3 1,9 0,8 1,2
19 14,3 20,2 9,2 12,9 5,6 8,0 4,5 6,4 3,5 4,9 2,2 3,2 1,4 2,0
24 16,4 23,0 10,5 14,7 6,4 9,0 5,2 7,2 4,0 5,6 2,6 3,6 1,6 2,3
37 21,1 29,1 13,5 18,6 8,3 11,5 6,7 9,2 5,1 7,1 3,3 4,5 2,1 2,9
48 24,7 33,6 15,8 21,5 9,7 13,2 7,8 10,6 6,0 8,1 3,9 5,2 2,4 3,3
52 25,9 35,2 16,6 22,5 10,2 13,8 8,2 11,1 6,3 8,5 4,0 5,5 2,5 3,5
61 28,6 38,5 18,3 24,6 11,3 15,1 9,0 12,1 6,9 9,3 4,5 6,0 2,8 3,8
64 29,4 39,5 18,8 25,3 11,6 15,6 9,3 12,5 7,1 9,6 4,6 6,2 2,9 3,9
74 32,2 42,9 20,6 27,5 12,7 16,9 10,2 13,5 7,8 10,4 5,0 6,7 3,2 4,2
91 36,7 48,4 23,5 31,0 14,5 19,0 11,6 15,2 8,9 11.7 5,7 7,5 3,6 4,8
Temperature rise above 10 °C shown in grey background is not recommended.
The values in this table are based on the impl
...