SIST-TP CLC/TR 50174-99-1:2015
(Main)Information technology - Cabling installation - Part 99-1: Remote powering
Information technology - Cabling installation - Part 99-1: Remote powering
This Technical Report defines requirements and recommendations concerning limits for the application and operation of remote powering using cabling comprising balanced cabling components of Category 5 (minimum) as defined in EN 50173-1.
This Technical Report also describes:
- a set of specific implementations which are the basis of a mathematical model for the temperature increases in bundles of cables under remote powering conditions;
- a matching testing protocol used to provide data for the mathematical model;
NOTE The testing protocol was established in order to enable comparison of data from different sources in order to support the development of the mathematical model and to develop appropriate planning and installation rules as suggested by different installation conditions. It is not the role of CLC/TC 215 to develop test methods for balanced, or other, cables and the protocol defined in Annex B is not as such a test method.
- the mathematical model that is employed as the basis for the resulting requirements and recommendations.
Safety (electrical safety and protection, optical power, fire, etc.) and electromagnetic compatibility (EMC) requirements are outside the scope of this Technical Report and are covered by standards and regulations. However, information given in this Technical Report may be of assistance in meeting these standards and regulations.
Informacijska tehnologija - Polaganje kablov - 99-1. del: Daljinsko napajanje
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
SIST-TP CLC/TR 50174-99-1:2015
01-junij-2015
Informacijska tehnologija - Polaganje kablov - 99-1. del: Daljinsko napajanje
Information technology - Cabling installation - Part 99-1: Remote powering
Ta slovenski standard je istoveten z: CLC/TR 50174-99-1:2015
ICS:
33.040.50 Vodi, zveze in tokokrogi Lines, connections and
circuits
35.110 Omreževanje Networking
SIST-TP CLC/TR 50174-99-1:2015 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST-TP CLC/TR 50174-99-1:2015
TECHNICAL REPORT
CLC/TR 50174-99-1
RAPPORT TECHNIQUE
TECHNISCHER BERICHT
April 2015
ICS 35.110
English Version
Information technology - Cabling installation - Part 99-1: Remote
powering
This Technical Report was approved by CENELEC on 2015-04-06.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,
Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2015 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. CLC/TR 50174-99-1:2015 E
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Contents
Foreword . 4
Introduction . 5
1 Scope . 6
2 Normative references . 6
3 Terms, definitions, abbreviations and symbology . 6
3.1 Terms and definitions . 6
3.2 Abbreviations . 7
3.3 Symbology . 7
4 Overview . 7
4.1 General . 7
4.2 Published standards . 8
4.3 Recent developments . 9
4.4 Basic principles of remote powering . 10
4.5 Testing protocols and mathematical modelling . 10
5 Application of remote powering . 10
5.1 Channel length . 10
5.2 Cables of Category 5 (minimum) in EN 50173-1 . 11
5.3 Installation environment . 12
5.4 Cable bundles . 12
5.5 Connecting hardware of Category 5 (minimum) in EN 50173-1 . 13
5.6 Pathways and pathway systems . 13
6 Operation . 14
6.1 Design margin . 14
6.2 Cable bundle temperature and construction . 14
6.3 Range of temperature rises . 14
6.4 Installation guidance . 16
6.5 Record-keeping . 16
6.6 Cabling acceptance and trouble-shooting testing . 16
Annex A (informative) Powering concepts . 17
A.1 Principles . 17
A.2 Mathematical treatment . 17
A.3 Power dissipation . 19
Annex B (normative) Test protocol . 20
B.1 Background . 20
B.2 Test set-up . 20
B.3 Current delivery and measurement accuracy . 22
B.4 Test conditions . 22
B.5 Installation environment . 22
B.6 Data submission. 23
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Annex C (normative) Temperature rise modelling . 25
C.1 Model basics . 25
C.2 Power dissipated (P) . 25
C.3 Temperature difference from ambient temperature to bundle surface (∆T ) . 26
u
C.4 Temperature difference from bundle surface to bundle centre (∆T ) . 26
th
C.5 Temperature variation within the bundle (∆T(x)) . 27
C.6 Alternative presentation of the model . 27
Bibliography . 28
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Foreword
This document (CLC/TR 50174-99-1:2015) has been prepared by CLC/TC 215
"Electrotechnical aspects of telecommunication equipment".
Attention is drawn to the possibility that some of the elements of this document may be the
subject of patent rights. CENELEC [and/or CEN] shall not be held responsible for identifying
any or all such patent rights.
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Introduction
EN 50174 series specify the specification, planning and practices applicable to installation of
telecommunications cabling.
Balanced cabling in accordance with EN 50173-1 is increasingly used to provide power as well
as telecommunication services to a wide range of terminal equipment. This Technical Report
examines the effects of remote powering (i.e. thermal heating) on installed cabling.
The components considered are of those specified in EN 50173-1. The components of
Category 5 as defined in EN 50173:1995 were not specified in terms of current carrying
capacity etc.; they are not supported by this Technical Report.
This Technical Report supports recognized application standards for power feeding produced
by IEEE (IEEE 802.3at) but is not restricted to the current feeding specification of that
standard.
The delivery of POTS, ISDN, PoE and PoEplus using fully energized bundles of up to
100 cables in accordance with EN 50288-X-1 in ventilated pathways is not considered to
represent a problem and is not considered in this Technical Report. In addition, there is no
reported evidence of such installations of those remote powering applications producing
problems in unventilated conditions. As a result, this Technical Report will only consider such
situations if the modelling and subsequent testing of cabling implementations indicates any
cause for concern.
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1 Scope
This Technical Report defines requirements and recommendations concerning limits for the
application and operation of remote powering using cabling comprising balanced cabling
components of Category 5 and above as defined in EN 50173-1.
This Technical Report also describes:
• a set of specific implementations which are the basis of a mathematical model for the
temperature increases in bundles of cables under remote powering conditions;
• a matching testing protocol used to provide data for the mathematical model;
NOTE The testing protocol was established in order to enable comparison of data from different sources in order
to support the development of the mathematical model and to develop appropriate planning and installation rules as
suggested by different installation conditions. It is not the role of CLC/TC 215 to develop test methods for balanced,
or other, cables and the protocol defined in Annex B is not as such a test method.
• the mathematical model that is employed as the basis for the resulting requirements and
recommendations.
Safety (electrical safety and protection, optical power, fire, etc.) and electromagnetic
compatibility (EMC) requirements are outside the scope of this Technical Report and are
covered by standards and regulations. However, information given in this Technical Report may
be of assistance in meeting these standards and regulations.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and
are indispensable for its application. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments)
applies.
EN 50173 series, Information technology – Generic cabling systems
EN 50173-1:2011, Information technology – Generic cabling systems – Part 1: General
requirements
EN 50174 series, Information technology – Cabling installation
EN 50174-2:2009 + A1:2011 + A2:2014, Information technology – Cabling installation – Part 2:
Installation planning and practices inside buildings
3 Terms, definitions, abbreviations and symbology
3.1 Terms and definitions
For the purposes of this document, the terms and definitions given in EN 50173 series and in
EN 50174 series and the following apply.
3.1.1
requirement met by design
requirement that does not require testing and where conformance may be achieved either by
selection of appropriate components and their installation techniques or by conformance of a
related parameter
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3.1.2
remote powering
supply of electrical power to application specific equipment via balanced cabling
3.2 Abbreviations
For the purposes of this document, the abbreviations given in EN 50173 series and the
following apply.
d.c., DC direct current
U/UTP unscreened cable with unscreened balanced cable elements
F/UTP foil screened cable with unscreened balanced cable elements
S/FTP screened cable with foil screened balanced cable elements
3.3 Symbology
For the purposes of this document, the following symbols are used.
total temperature rise between the ambient temperature (or that of the
∆T
unpowered bundle) and the centre of the bundle
temperature rise between the outer surface and the centre of the bundle
∆T
th
temperature rise between the ambient temperature (or that of the unpowered
∆T
u
bundle) and the outer surface of the bundle
i the current per conductor (A)
c
n number of conductors per cable carrying remote powering current (i )
c c
N number of cables carrying remote powering current
R
average d.c. resistance per unit length (Ω/m) of conductors carrying remote
powering current
ρ constant relating to cable construction
th
ρ constant relating to installation environment
u
4 Overview
4.1 General
The principal concerns associated with the delivery of power are:
a) increases in the operating temperature of the cables (exceeding their specified
operating temperature);
b) damage to connecting hardware contacts where mating and de-mating occurs while the
power supply current is flowing;
c) the associated increase of channel attenuation/insertion loss, due to the increased
temperature of installed cables, which unless balanced by reduced installed lengths will
have a negative effect on channel ACR/PSACR (and may be associated with increased
system bit error rates).
This Technical Report demonstrates that the thermal impact of remote powering is proportional
to the number of cables in a bundle (and/or the number of bundles installed in a close proximity
to others) and the length over which that installation condition is maintained. Figure 1 is a
schematic of the distribution cabling subsystems defined by EN 50173-2 and EN 50173-6
(together with the supporting backbone cabling common to both standards).
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BD FD
Fixed backbone cabling
EQP C C C C EQP
Distribution Backbone
No. of
cables in a bundle Cord Cord
or group of bundles
FD/SD TO/
Fixed distribution cabling
SO
EQP C C C C EQP
Key
BD building distributor of EN 50173-X
C connection positions
EQP equipment
FD floor distributor of EN 50173-2
SD service distributor of EN 50173-6
SO service outlet of EN 50173-6
TO telecommunications outlet of EN 50173-2
Figure 1 — Schematic of cabling in accordance with EN 50173 series standards
showing cable bundle trends
The fixed cabling in both the backbone and distribution cabling typically contains multiple
bundles of cables as they leave the distributors. In the distribution cabling, the number of
bundles in a group and then the number of cables in a bundle reduces towards the outlets
whereas the backbone bundles tend to be consistent along their length. Connections to
equipment at either end is made via cords which tend to be installed as single components or
in small groups - and even where larger bundles are created they are accessible and are able
to be re-dressed to reduce any identified thermal impact.
As a result, the focus of this Technical Report in relation to thermal impact is on the fixed
cabling.
4.2 Published standards
4.2.1 ISO/IEC TR 29125:2010
ISO/IEC TR 29125:2010 contains information on temperature rises found at the centre of cable
bundles for cables of Category 5 and above and for currents of up to 360 mA per conductor.
This information was used during the development of IEEE 802.3at to define the limits of power
delivered.
ISO/IEC TR 29125:2010 suggests that cables of a higher category produce lower temperature
increases for a given current and bundle size. However, all categories of cable currently have
the same maximum d.c. resistance specification. This specification is based on the minimum
conductor diameter to meet the transmission performances taking into account all the possible
designs. Thus, the actual conductor diameter and the d.c. resistance per unit length of the
conductor may have more influence than the cable category.
ISO/IEC TR 29125:2010 suggests that the temperature rise increases as both the current per
pair increases and as the bundle size increases. Based on these assumptions
ISO/IEC TR 29125:2010 gives figures for increases of temperature according to the current
and the bundle size. However, external surfaces of the bundles were in open air, allowing
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cooling by radiation and convection. This is not representative of the full range of pathway
systems, and when bundles are installed in unventilated cable management systems or in
insulating materials, the temperature rise will be higher.
4.2.2 EN 50173-1:2011
EN 50173-1:2011 specifies the d.c. loop resistance requirements of generic cabling channel
and links.
EN 50173-1:2011 specifies the current carrying capacity requirements of generic cabling
channels which are linked to the 10 °C temperature rise suggested in ISO/IEC TR 29125:2010
at the centre of a bundle of 100 cables for a current of 300 mA per conductor (all conductors
powered). Additionally it is stated that:
a) relevant application standards and manufacturers‘ instructions shall be consulted with
reference to safety aspects of power feeding;
b) care shall be taken when using multi-unit or bundled cables due to the possible rise of
temperature within the cabling components that may degrade channel performance.
4.3 Recent developments
4.3.1 EN 50173-6
EN 50173-6 specifies generic cabling for distributed building services which is expected to be
exploited by a wide range of remote powering solutions including those of IEEE 802.3 and
other proprietary products.
4.3.2 IEEE 802.3
IEEE 802.3 is considering the delivery of higher powers than those specified in IEEE 802.3at.
A revision of ISO/IEC TR 29125:2010 is in development at this time.
4.3.3 Other remote powering solutions
Installed cabling may be subjected to currents and voltages other than those defined for
IEEE 802.3 (both now and in the future).
There are many building services such as access control, environmental monitoring and
lighting that are designed to operate over the cabling within the scope of this Technical Report.
It is common for these services to be the responsibility of different groups within an
organization. Management of the power applied is important to control rises in cable
temperature within bundles of cables that may carry multiple services, each of which may have
different temperature dependencies in relation to the transmission of data traffic.
However, it is assumed that the equipment incorporates safe signal circuitry complying with the
SELV circuit and the TNV requirements as defined in the EN 60950 series.
4.3.4 EN 50173-1
A revision of EN 50173-1:2011 is expected to modify the requirements for both d.c. loop
resistance and current carrying capacity in order to better control the application and outcomes
of remote powering over generic cabling.
The modifications to the d.c. loop resistance requirements are intended to prevent the
installation of fixed cables that have d.c. loop resistance higher than those of Category 5 and
are expected to include the following:
a) the existing channel requirements will be augmented by a “met by design” requirement for
the d.c. loop resistance per unit length;
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b) the link requirements, which are already length dependent, will be modified as per any
changes to the channel limits mentioned above to define requirements at 20 °C (to which
measured values are required to be corrected).
The existing current carrying capacity requirements are expected to be deleted and to be
replaced with:
1) a restriction of current carrying capacity to 0,75 A per conductor under continuous
operation (as specified in EN 50173-1:2011, Annex D);
2) a warning that this is:
- not the current carrying capacity if mating or de-mating under load;
- not a guide for application support;
3) a requirement that any equipment connected to the channels or applications operating
over them shall be fitted with over-current protection not exceeding 0,75 A per conductor.
Additionally, reference is likely to be made to this Technical Report and any resulting
requirements or recommendations that may be introduced to EN 50174 series standards.
4.4 Basic principles of remote powering
Annex A contains details of the basic principles of remote powering used within this Technical
Report.
4.5 Testing protocols and mathematical modelling
Annex B contains details of a test protocol that allows test data obtained from a variety of
independent test facilities to be directly compared.
That data has been used to develop and confirm the basic mathematical model of Annex C.
The testing protocol and mathematical model address the following installation conditions:
a) varying cable constructions and diameters;
b) bundles with differing quantities of cable of a given construction and diameter;
c) a variety of installation methods (several tight bundles, air between bundles);
d) installation environment: free ventilation, closed compartment, insulated;
e) pathway systems: cable ladder/wire basket, cable tray, duct.
5 Application of remote powering
5.1 Channel length
5.1.1 Installed cabling performance
The channel requirements of EN 50173-1 are temperature independent i.e. they are required to
be met at the operating temperature of the channel. However, any temperature rise due to
power feeding in combination with the ambient temperature produces an increase in
attenuation/insertion loss of the installed cabling.
For cables specified in the reference implementations of the EN 50173 series standards, the
attenuation increase is assumed be, for operating temperatures above 20 °C, 0,2 % per °C for
screened cables and 0,4 % per °C (20 °C to 40 °C) and 0,6 % per °C (> 40 °C to 60 °C) for
unscreened cables. In order for the cabling performance to meet a given class, either the
length of the channel has to be reduced accordingly or the conductor diameter has to be
enlarged.
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It should be noted that testing the transmission parameters of the installed infrastructure
immediately following its installation will not show any impact of increased ambient temperature
as the cables will not be “under load” so planning of cable lengths has to take into account the
predicted temperature increases.
5.1.2 Reduction in channel length
Table 1 provides general guidance on the worst-case reduction of channel lengths which can
be applied to all cabling using cables specified in the reference implementations of the
EN 50173 series standards.
Table 1 – The impact of temperature on channel length
Total length of cords
m
10 15 20
Temperature Channel length
o
C m
20 100 98 95
25 98 96 93
30 97 94 91
35 95 92 89
40 93 90 87
45 90 87 85
50 86 84 82
55 83 81 79
60 80 78 76
The reduction in channel lengths and, by implication, link lengths with increased temperature
results in a reduction of the area served by the distributor as described in the EN 50173 series
standards.
5.1.3 Application support
Increased operating temperatures may reduce the length over which an application can be
supported.
Cable bundles may contain a mix of applications - some of which have no remote powering
content and others within which the levels of remote powering may be continuous or variable.
As a result, the combined thermal impact should be considered for all the applications to be
supported. To maximize the continuity of application support, the predicted thermal impact
shall be documented and appropriate planning shall be employed in terms of selection of
components, installation environment and installation techniques.
5.2 Cables of Category 5 and above in EN 50173-1
5.2.1 Cable construction
The mathematical model of Annex C indicates that the temperature rise (∆T ) within a given
th
cable bundle and a given current per conductor (i ) is influenced by the conductor resistance
c
(R) and a constant (ρ ) which relates to the cable construction and materials.
th
The total temperature rise (∆T) is proportional to R.
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At the time of publication of this Technical Report, the mathematical model of Annex C adopts
the following values for ρ :
th
a) 5 for U/UTP cable constructions;
b) 3 for F/UTP cable constructions;
c) 2,75 for S/FTP cable constructions.
See C.4.2 for further information.
5.2.2 Maximum conductor surface temperature
Cables specified in the reference implementations of the EN 50173 series of standards are
required to operate at temperatures of ≤ 60 °C.
Cable suppliers may provide products that have specified maximum operating temperatures in
excess of this requirement. The current applied to cables, in conjunction with the intended
ambient temperature, shall not cause their operating temperature to rise above that specified
by the cable supplier.
5.3 Installation environment
The mathematical model of Annex C indicates that the temperature rise of the surface of a
cable bundle above ambient (∆T ) for a given current per conductor (i ) and cable construction
u c
is influenced by the conductor resistance (R), the cable diameter (d) and a constant (ρ ) which
u
relates to the installation environment.
The total temperature rise (∆T) is proportional to R. The temperature rise at the outer surface
of a cable bundle (∆T ) is inversely proportional to the diameter of the cables (d) that constitute
u
the cable bundle.
At the time of publication of this Technical Report, the mathematical model of Annex C adopts
the following values for ρ for ∆T ≤ 40 °C (from an ambient of 20 °C);
u
a) for ventilated conditions:
- ρ = 0,15 for all cable constructions;
u
b) for conduit (filled to at least 40 % capacity as defined in EN 50174-2):
- ρ = 0,19 (ffs) for F/UTP cable constructions;
u
- other cable constructions are ffs;
c) for insulated conditions:
- ρ = 0,70 for U/UTP and F/UTP cable constructions;
u
- ρ = 0,87 for S/FTP cable constructions.
u
See C.3.2 for further information.
5.4 Cable bundles
5.4.1 Quantity of cables (N)
The mathematical model of Annex C indicates that the temperature rise for different values of
x
N is proportional to N where x = 0,6 to 0,75.
NOTE In a bundle of N = 96, the temperature rise is 2,3 to 2,9 times that for N = 24.
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5.4.2 Bundle temperature
The mathematical model of Annex C indicates, for a given cable type and installation
environment, that for cable bundles of N ≤ 24 the temperature rise at the outer surface of a
cable bundle (∆T ) is generally ≥ 80 % of the total temperature rise of the centre of the bundle.
u
For this reason, and for simplicity of discussion, it is assumed that all cables in a bundle
experience the same temperature rise (i.e. that of the centre cable of the bundle).
NOTE For larger bundles, ∆T falls below the ≥ 80 % figure quoted above but for the purposes of data handling,
u
the same assumption is applied.
5.4.3 Bundle construction
There is minimal difference in temperature rise between bundles that are randomly assembled
and those that are very carefully organized.
5.5 Connecting hardware of Category 5 and above in EN 50173-1
5.5.1 Continuous current per conductor
As mentioned in 4.3.4, the connecting hardware specified in the EN 50173 series standards is
required to support a continuous operating current of ≥ 0,75 A per conductor at 60 °C.
Connecting hardware suppliers may provide products that have specified maximum operating
currents in excess of this requirement. The current applied to each conductor of the connecting
hardware shall not exceed the value specified by the connecting hardware supplier.
5.5.2 Mating and de-mating under current load
The contacts of connecting hardware are at risk of damage when those contacts are mated or
de-mated under load (i.e. when carrying current).
EN 60512-9-3 specifies an endurance test for connecting hardware under conditions of mating
or de-mating under a disconnection load of 600 mA per conductor.
NOTE 1 300 mA is the operational current that under conditions of de-mating can cause 600 mA to flow through the
last connector contact to de-mate.
EN 60512-9-3 refers to EN 60512-99-001, which defines an associated test schedule. This
schedule requires connecting hardware to meet the required performance after 100 cycles (as
compared to
...
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