BACKBONE DISTRIBUTION ▲ = Normative (Shall) ▲ = Informative (Should/Recommend) Siemon Cabling System Training Manual IS-1821-01 Rev. M 5-1 SECTION OBJECTIVES At the successful completion of this section on Backbone Distribution, the student shall be able to: I. Recall the requirements associated with the annexes A and B of this manual. II. Recall and list the Siemon-approved components and the relevant specifications which comprise the Backbone distribution of the Siemon Cabling System. III. Describe the compliant cabling topology to facilitate the Backbone distribution for the Siemon Cabling System. IV. Define and recall the prescribed distance limits for Backbone cabling, and patch cords and equipment cables, which permit compliance to the Siemon Cabling System. V. Select the approved copper and optical fiber components and configurations, which comprise the Backbone distribution of the Siemon Cabling System. VI. Describe the requirements for fire stopping and other safety issues as they apply to the Siemon Cabling System. VII. Recall the various techniques and know the approved types and methods for designing and installing Backbone pathways to facilitate Backbone distribution.
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SECTION OBJECTIVES
At the successful completion of this section on Backbone Distribution, the student shall be able to:
I. Recall the requirements associated with the annexes A and B of this manual.
II. Recall and list the Siemon-approved components and the relevant specifications which comprise the Backbone distribution of the Siemon Cabling System.
III. Describe the compliant cabling topology to facilitate the Backbone distribution for the Siemon Cabling System.
IV. Define and recall the prescribed distance limits for Backbone cabling, and patch cords and equipment cables, which permit compliance to the Siemon Cabling System.
V. Select the approved copper and optical fiber components and configurations, which comprise the Backbone distribution of the Siemon Cabling System.
VI. Describe the requirements for fire stopping and other safety issues as they apply to the Siemon Cabling System.
VII. Recall the various techniques and know the approved types and methods for designing and installing Backbone pathways to facilitate Backbone distribution.
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BACKBONE CABLING
The Backbone cabling extends from the Main Cross-connect to the Horizontal Cross-connects and includes the Main Cross-connect, the Intermediate Cross-connect, the connecting hardware dedicated to the Backbone cabling, and the cables that join them. The Backbone cabling also includes the mechanical terminations and jumpers/patch cords used for Backbone-to-Backbone connectivity. The Backbone cabling does not include cables in the Telecommunications Rooms, Equipment Rooms, or Entrance Facilities that connect directly to customer premises equipment (CPE).
The following requirements and recommendations are intended to assure that the Backbone cabling system can accommodate present and future information technologies that are introduced over its planning period.
EMI Considerations for Backbone Cabling
Electromagnetic Interference (EMI) is an important consideration during the design and installation of Backbone cabling and pathways.
� – 1 To avoid problems caused by electromagnetic emissions from power cables and from premises equipment, the requirements of Annex B of this manual shall be met for all Backbone cabling and pathways.
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Backbone Cabling Structure
Topology
� – 2 The Backbone cabling shall use the conventional hierarchical star topology.
� – 3 There shall be no more than two subsystems of cross-connects in the Backbone cabling. From the Floor Distributor/Horizontal Cross-connect, no more than one cross-connect shall be passed through to reach the Campus Distributor/Main Cross-connect.
The first subsystem is the cabling from the Campus Distributor/Main Cross-connect. The second subsystem is the cabling from the Building Distributor/Intermediate Cross-connect. The Floor Distributor/Horizontal Cross-connect is not considered to be part of the Backbone cabling. The implication of the two levels of hierarchy in the Backbone system is that no more than three cross-connects can exist along the cabling route between any two Floor Distributor/Horizontal cross-connects.
The limitation of two levels of cross-connects is imposed to limit signal degradation for passive systems and to simplify moves, adds and changes. This limitation may not be suitable for facilities which have a large number of buildings or those that cover a large geographical area, such as universities, industrial parks and military bases. In these cases it may be acceptable to divide the entire facility into smaller areas within the scope of this document and then connect these areas together.
The figures shown on the preceding two pages represent a typical Backbone cabling star configuration with two buildings. If a logical bus, ring or tree is required, the star topology provides the flexibility needed to implement them through connections to the Campus Distributor/Main Cross-connect or Building Distributor/ Intermediate Cross-connects.
Backbone Cross-Connect
The Backbone cross-connect (CD/MC and/or BD/IC) is composed of cross-connections or interconnections.
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Backbone Cabling Diagrams
Cross Connections
Whereas a "cross-connect" is defined as a means to enable the termination of cables and their interconnection or cross-connection using jumpers/patch cords or equipment cables, a "cross-connection" refers to a configuration in which cables or jumpers/patch cords are used to connect between separate distribution fields that serve Horizontal cabling, Backbone cabling and premises equipment.
� – 4 Cross-connections shall be used for connections between Horizontal and Backbone cabling, between first level Backbone and second level Backbone cabling and for connections between Backbone cabling and premises equipment with multiple port outputs (such as 25-pair connectors).
Interconnections
Interconnections provide direct connections between premises equipment and Horizontal or Backbone distribution fields by way of equipment cables that serve a single output port.
� – 1 Interconnections may be used for connections between premises equipment with single port output connectors (such as modular jack or optical fiber connectors) and distribution fields that serve Horizontal or Backbone cabling.
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Note: Interconnections shall not be permitted for attachment of Horizontal cabling directly to Backbone cabling, and first and second level Backbone cabling.
Locations of Backbone Cross-Connects
While a CD/MC typically serves an entire campus or building, BD/ICs serve only a portion of the installation. BD/ICs are useful for establishing Backbone service zones based on occupancy or on the physical layout of the building, campus, or infrastructure. It should also be noted that Campus Distributor/Main Cross-connect and Building Distributor/Intermediate Cross-connects often occupy the same spaces as Floor Distributors/Horizontal Cross-connects.
� – 2 In order to make optimum use of a star topology, it is recommended that the Campus Distributor/Main Cross-connect be located near the geographic center of the area that it is intended to serve.
� – 5 Connecting hardware shall not be installed in locations that are not specifically intended for telecommunications use or where they may violate applicable codes and regulations.
Although it is sometimes convenient to place a cross-connect block in a ceiling, this practice limits the serviceability of the cabling system and may violate applicable codes and regulations.
Application Specific Devices
� – 6 All devices that are specifically intended to support a given application shall be installed external to the Campus Distributor/Main Cross-connect or Building Distributor/Intermediate Cross-connect.
This requirement assures that the implementation of new telecommunications applications will require minimal change to the telecommunications cabling infrastructure. Examples of application-specific devices include media filters, baluns, MAUs, protection apparatus, splitters and adapters. The use of these devices is specifically outside the scope of the Siemon Cabling System, as well as industry cabling standards.
Bridged Taps
� – 7 Bridged taps shall not be used as part of the Backbone cabling.
As is the case with horizontal cabling, bridged taps (parallel connections of the same cable pairs) do not comply with the requirement for star topology and are severely detrimental to the transmission properties of the cabling system.
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Splices
� – 8 When used, UTP and optical fiber splices shall be kept accessible and shall not be used for routine cabling system changes.
� – 3 The use of both UTP and optical fiber splices in the Backbone cabling should be limited to as few as possible.
� – 9 Splices shall not be used on F/UTP and S/FTP cables.
UTP Splice Limitations
� – 10 Where UTP copper cable is used in the Backbone (campus Backbone and building Backbone), the number of splices shall be kept to the minimum required by the physical system design or installation constraints.
� – 11 When used, splices shall be constructed using insulation-displacement type connectors and housed in enclosures appropriate for the environment.
Note: UTP splices used in the Backbone cabling are intended for voice applications only.
Optical Fiber Splice Limitations
� – 12 Optical fiber splices used in the Backbone shall be limited to an acceptable number which is based on an acceptable link attenuation budget.
Cabling Directly Between Telecommunications Rooms
If requirements for ‘bus’ or ‘ring’ configurations are anticipated, cabling directly between Telecommunications Rooms may be done. Such cabling is in addition to the connections for the basic star topology.
The installation of Backbone cable runs that supplement the basic star topology is optional, and it should be noted that the installation of Backbone pathways between rooms on the same floor is also optional in the Siemon Cabling System.
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Recognized Backbone Cables The following types of cable are supported by the Siemon Cabling System. These types are:
a) Four-pair 100 Ω balanced twisted-pair (UTP, F/UTP, F/FTP, S/FTP),
b) *Multi-pair 100 Ω unshielded twisted-pair (UTP),
c) 62.5/125 µm OM1 and 50/125µm OM2, including laser optimized OM3 & OM4 multimode optical fiber cable,
d) Singlemode optical fiber cable.
*Multi-pair Cables
Multi-pair Cables are identified as cables that contain more than four pairs that are covered by an overall sheath/jacket.
� – 13 Multi-pair cable(s) used in the Backbone are intended to support voice applications only, and shall be tested for continuity.
Other cable types that are used to serve special needs are considered to extend beyond the minimum requirements of this manual. These "other" media choices are outside the scope of the Siemon Cabling System. Examples of additional Backbone media include 150 Ω STP-A cabling (Token Ring) and 75 Ω coax (Cable TV). These and other application-specific cables may be used, but only in addition to the minimum requirements of the Siemon Cabling System.
Backbone Cabling Component Specifications
Components used in the Backbone Cabling System are subject to the following requirements:
Backbone Twisted-Pair Cables
� – 14 Balanced twisted-pair cables shall be Qualified Cables for use in the Siemon Cabling System. Refer to Ally Website, www.siemon.com/ally for Qualified Cables.
Backbone Optical Fiber Cables
� – 15 Multimode and singlemode optical fiber cables shall be Qualified Cables for use in the Siemon Cabling System. Refer to Ally Website, www.siemon.com/ally for Qualified Cables.
When a qualified cable is not available to meet specific installation needs, the Certified Designer is responsible for submitting Form 1, Siemon Cabling System Request For Exception, prior to installation for approval.
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Backbone Connecting Hardware
� – 16 All connecting hardware used with 100 Ω balanced twisted-pair cables and all connecting hardware used with optical fiber cables shall be provided by Siemon.
BACKBONE PATCH CORD/EQUIPMENT CORD ASSEMBLIES
Backbone Modular Cord Assemblies/Channel Model
� – 17 All patch cords and equipment cables used to cross-connect or interconnect 100 Ω balanced twisted-pair, 62.5/125 µm and 50/125 µm multimode and singlemode optical fiber cabling for use in a channel model warranty, shall be manufactured by Siemon to receive applications assurance. For field terminated cable assemblies, see note below.
Note: The construction of patch cords and equipment cables incorporating double ended S110P or S210P or TERA plugs can be performed by the Certified Installer (Company). The use of which in a Channel Model qualifies the channel for applications assurance under the Siemon System Warrant
For category 5e or higher modular to S110P or S210P assemblies, the Certified Installer (company) can purchase these factory assembled or they may be purchased as double-ended modular-to-modular assemblies (typically double the length) cut in half and terminated to the S110P or S210P on the cut end, leaving the factory assembled modular plug as it is.
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Choosing Backbone Cabling Media
Considerations that factor into the selection and quantity of Backbone cable pairs and fibers include:
• The planning life of the Backbone system • The bandwidth requirements for planned applications • The number of Work Areas served by a given Backbone segment
The first two criteria listed above are unique to each installation and are left to the discretion of the Certified Installer.
Whenever possible, the different service requirements should first be determined. It is often convenient to group similar services together in a few categories such as voice, display terminal, Local Area Networks (LAN) and other digital connections. Within each group, individual types should be identified and required quantities projected.
When uncertain, use ‘worst case’ scenarios when evaluating different Backbone cabling alternatives. The higher the uncertainty, the more flexible the Backbone cabling system needs to be.
Each recognized cable has individual characteristics that make it useful in a variety of situations. A single cable type may not satisfy all the user requirements at a site. It is then necessary to use more than one medium in the Backbone cabling.
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Building Backbone Cabling
The following requirements and recommendations are provided for Backbone cabling runs within a building.
Optical Fiber Cabling
� – 18 For each building Backbone subsystem that is greater than 90 m (295 ft) in length, optical fiber cable shall be provided if support for data applications is required.
Requirement: Optical fiber cable
This requirement assures that high-speed data applications can be supported between Campus Distributor/Main Cross-connect and Floor Distributor/Horizontal Cross-connect. Fiber is desirable for building Backbone runs because of its bandwidth capability and the fact that it occupies less pathway space (per delivered bandwidth) than balanced twisted-pair.
� – 4 It is recommended that at least two optical fiber cores/strands be provided for every known application to be served by the building Backbone over its planning period. A growth factor of 100% should be provided.
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Balanced Twisted-Pair Cabling
� – 5 For each building Backbone run, balanced twisted-pair cable should also be provided.
Recommendation: Balanced twisted-pair cable, regardless of length
� – 19 If the building Backbone run is less than or equal to 90 m (295 ft) in length, and optical fiber is not installed, category 5e or higher Backbone cable shall be provided if support for data applications is required.
Requirement: Balanced twisted-pair Cat. 5e or higher
This requirement assures that both voice and high-speed data applications can be supported between Campus Distributor/Main Cross-connect and Floor Distributor/ Horizontal Cross-connect.
� – 6 It is recommended for sizing multi-pair Backbone that at least two cable pairs (category 3 or higher) be provided for each Work Area served by the building Backbone segment.
This recommendation provides for a minimum of one pair per Work Area to support voice applications and at least one additional pair for growth or for ancillary devices.
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Campus Backbone Cabling
The following requirements and recommendations are provided for all Backbone cabling runs that extend between buildings.
Optical Fiber Cabling
� – 20 For each campus Backbone run, optical fiber cable shall be provided if support for data applications is required.
Fiber is the preferred media for campus runs because it typically provides more bandwidth than twisted-pair cabling and is immune to ground loop problems that may occur between buildings for some types of metallic media.
� – 7 It is recommended that at least two optical fiber cores/strands be provided for every known application to be served by the campus Backbone over its planning period. A growth factor of 100% should be provided.
For this example, a 36-fiber campus Backbone cable is recommended. Although this is a recommendation, consideration should be given for the environment in which these additional strands will be stored.
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Balanced Twisted-Pair Cabling
� – 8 For each campus Backbone run, balanced twisted-pair cable should also be provided.
� – 9 It is recommended for sizing multi-pair Backbone that at least two cable pairs (category 3 or higher) be provided for each Work Area served by the campus Backbone segment.
This recommendation provides for a minimum of one pair per Work Area to support voice applications and at least one additional pair for growth or for ancillary devices.
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BACKBONE CABLING DISTANCES
The following requirements and recommendations apply to all portions of the Backbone cabling. The connection of multiple campuses or buildings that extend beyond the distance limits specified in this section are outside the scope of the Siemon Cabling System. Equipment manufacturers, application standards and systems providers should be consulted before selecting the Backbone medium.
Backbone Maximum Lengths Limits
�– 21 The total channel length between the Campus Distributor/Main Cross-connect and any Floor Distributor/Horizontal Cross-connect shall not exceed the following length limits:
• 3,000 m (9,840 ft) for singlemode (OS1) optical fiber,
• 2,000 m (6,560 ft) for 62.5/125 µm or 50/125 µm multimode (OM1-OM4) optical fiber,
• 2,000 m (6,560 ft) for balanced twisted-pair for PBX/Class A (100 kHz) applications
Note: Although the North American standards specify 800 m (2,624 ft.) for voice, Siemon and ISO allow longer distances for these lower performing applications.
• 200 m (656 ft) for balanced twisted-pair for Class B (≤ 1 MHz) applications.
For data Class C, D, E, EA, F and FA applications over copper:
• 100 m (328 ft) for balanced twisted-pair (per Backbone segment when providing a two-level Backbone).
Note: Although maximum channel distance listed above may be capable for some applications, certain high-speed data rate applications require channel/subsystem distances that are significantly reduced. Refer to the Applications Guide in Annex C.
Note 2: Balanced twisted-pair Backbone cabling that exceeds 100 m (328 ft) are typically designed to support voice applications.
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Backbone Cabling Links and Channels
For the purposes of this section, two terms are used to distinguish between Backbone cabling subsystems with and without equipment cables. These terms are Backbone Permanent Link model and Backbone Channel model.
Backbone Permanent Link Model
A Backbone Permanent Link model includes the Backbone connecting hardware and the cables which extend between these connecting hardware fields.
Backbone Channel Model
A Backbone Channel model includes all components of the Backbone Permanent Link including jumpers/patch cords and equipment cables.
Campus Distributor/Main Cross-Connect to Entrance Point
� – 10 Cable lengths between the entrance point and the Campus Distributor/Main Cross-connect should be documented in the applicable cable records. For more information on cable records, see the Administration section of this manual.
Cable Slack
During the installation of Backbone cable, extra slack should be provided on both ends, in order to facilitate termination operations and to accommodate possible relocation of terminations in the telecommunications rooms.
� – 11 For Backbone terminations that service the Floor Distributor/Horizontal Cross-connect, a minimum of 3 m (10 ft) of cable slack is recommended. Backbone terminations at the Campus Distributor/Main Cross-connect and Building Distributor/Intermediate Cross-connects should also have at least 3 m (10 ft) of cable slack.
It should be noted that cable slack constitutes part of the total length allowance for Backbone cabling.
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Equipment Connections
Although equipment cables are an integral part of the telecommunications network. Therefore, the following requirements shall be met to assure that applications will operate properly over the Backbone cabling system.
Maximum Length of Cross-Connect Jumpers/Patch Cords and Equipment Cables
� – 22 The total combined length of category 5e and higher balanced twisted-pair cross-connect jumpers/patch cords and equipment cables in a channel shall be determined by the following formula:
C = 102*- B (1 + D)
C = Combined length of patch cords/jumpers and equipment cables on both ends of a Backbone channel
B = Length of fixed Backbone cable D = .2 for UTP; .5 for shielded systems * ISO uses 105 for 5e. We have chosen to be more stringent to provide
better channel performance. This also allows for formula consistency.
Maximum cable lengths in backbone cabling Length of Maximum combined length of
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For balanced twisted-pair if the formula is not utilized, the total combined length of cross-connect jumpers/patch cords between the CD/MC and BD/IC, or BD/IC and FD/HC, or CD/MC and FD/HC, and equipment cables shall not exceed 15 m (50 ft) in length if the Backbone channel is:
• ≤100 m (328 ft) for balanced twisted-pair and applications assurance is desired .
Example: If the length of the fixed UTP cabling (CD/MC to FD/HC) is 85 m (278 ft) long, then the combined length (both ends) of equipment cables and cross-connections may be up to 14 m (46 ft) long. However, if the length of the fixed cabling is 90 m (295 ft) long, then the combined length (both ends) of equipment cables and cross-connections may be up to only 10 m (33 ft) long.
BACKBONE CABLING PRACTICES
Backbone Cabling Installation Practices
� – 23 The installation practices specified in the Installation Practices section of this manual shall be followed.
� – 24 Grounding/Earthing and bonding requirements specified in the applicable codes and regulations shall be met.
BACKBONE PATHWAYS
Backbone pathways consist of building and campus pathways. The term Backbone replaces riser, house, feeder and building-tie cable terminology. Backbone pathways may be either vertical or Horizontal. Campus Backbone pathways extend between buildings. Building Backbone pathways are contained within a building.
Backbone pathway requirements and recommendations are intended to accommodate all types of telecommunications cable (voice, data, image, etc.). This section covers guidelines and recommendations on pathways used for Backbone cable distribution.
General Requirements/Recommendations For Backbone Cabling Pathways
Building Codes
� – 25 Backbone pathways shall be designed and installed to meet all applicable local and national building and electrical codes.
� – 26 The quantity, size and bend radius requirements of Backbone cables shall be known to determine the type and size of the Backbone pathway. An allowance for growth shall be provided.
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Grounding/Earthing and Bonding
� – 27 Grounding/Earthing and Bonding of Backbone pathways shall comply with all applicable codes and regulations.
Fire Stopping
� – 28 Properly designed fire stop systems shall be installed to prevent or retard the spread of fire, smoke, water, and gases through the building. This requirement applies to openings designed for telecommunications use that may or may not be penetrated by cables, wires, and raceways. Such systems shall comply with all applicable national and local fire protection codes.
Cable Protection
� – 29 Pathways shall be suitable for the environment in which they are installed and shall not be impeded by HVAC Ducts, electrical power distribution, or surrounding building space limitations.
Bend Radii
� – 30 Backbone pathways shall be installed or selected such that the minimum bend radius of Backbone cables is kept within manufacturer specifications both during and after installation.
� – 12 Minimum inside bend radius of Backbone pathways should not be less than ten times the maximum cable diameter to be installed.
Building Pathways
The ideal vertical Backbone pathway consists of Telecommunications Rooms located on each floor, which are vertically stacked one above the other and tied together by sleeves or slots.
In this context, the term ‘sleeve’ refers to a circular opening in a wall, ceiling or floor to permit the passage of cables between adjacent spaces. A ‘slot’ is the same as a ‘sleeve’, except that the shape of the opening is usually rectangular.
Backbone pathways encompass all pathway types as specified in the Horizontal Distribution section of this manual.
Cable Management
� – 31 A defined telecommunications cable pathway (i.e., A pathway that is specifically dedicated for telecommunications use), shall be used for cable management.
� – 32 Building pathway types used for Backbone cables which have similar design and type as Horizontal pathways shall comply with the requirements of the Horizontal section of this manual.
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Backbone Conduit Size
� – 13 The following charts are provided as a resource for design purposed only and should only be used for approximations.
EMT Conduit Fill for Backbone Cable Maximum recommended occupancy Minimum bend radius A B C D E Size Internal Total Area 1 Cable 2 Cables 3 Cables Steel Other designator diameter 100% 53% fill 31% fill and over layers sheaths 40% fill within sheath mm (in) mm (in) mm2 (in2) mm2 (in2) mm2 (in2) mm2 (in2) mm (in) mm (in)
NOTES 1 Column A is used when one cable is to be placed in conduit. 2 Column B is used when two cables share a conduit. The percentage fill is applied to straight runs with nominal offset equivalent to no more than two 90º bends. 3 Column C is used when three or more cables share a conduit. 4 Column D indicates a bend of 10X the conduit diameter for cable sheaths equipped with steel tape in the sheath. 5 Column E indicates a bend of 6 times the conduit diameter up to and including 53 (2) trade size, and 10 times the diameter above 53 (2) trade size conduit. 6 The number of cables that can be installed in a conduit can be limited by the allowed maximum pulling tension of the cables. 7 For large diameter cables, conduit fill is a factor of cable pulling tension. See pull tension information.
Pull Tension on Cables With the Use of Conduit Conduit sizing is directly related to the planned diameter of the cable and the maximum pull tension that can be applied to the cable without degradation of the cable transmission properties. The pull tension limit is based on the strength of the conduit (including sidewall pressure), the strength of the pull line, the geometry of the conduit system, and the strength of the cable. The position of the bends and length of the conduit system will affect the pull tension that will be imposed on a cable. For instance, pulling cable in one direction may cause a cable pull tension of 2700 N (600 lbf) whereas pulling from the opposite direction may cause a tension of 1350 N (300 lbf). The pull tension of the planned cable to be installed needs to be calculated in both directions.
NOTE: Cable pulling tensions may be reduced by using lubricants that are specially formulated for the composition of the cable.
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The following main contributory functions should be considered when calculating cable tensions. - The mass per unit length of cable. - The coefficient of friction between cable sheath and surfaces with which it will come in contact. - Deviations and inclinations.
RMC Conduit Fill for Backbone Cable
Maximum recommended occupancy Minimum bend radius A B C D E
Size Internal Total Area 1 Cable 2 Cables 3 Cables Steel Otherdesignator diameter 100% 53% fill 31% fill and over layers sheaths
40% fill within sheath
mm(in) mm(in) mm2 (in2) mm2 (in2) mm2 (in2) mm2 (in2) mm (in) mm (in)
NOTES 1 Column A is used when one cable is to be placed in conduit. 2 Column B is used when two cables share a conduit. The percentage fill is applied to straight runs with nominal offset equivalent to no more than two 90º bends. 3 Column C is used when three or more cables share a conduit. 4 Column D indicates a bend of 10X the conduit diameter for cable sheaths equipped with steel tape in the sheath. 5 Column E indicates a bend of 6 times the conduit diameter up to and including 53 (2) trade size, and 10 times the diameter above 53 (2) trade size conduit. 6 The number of cables that can be installed in a conduit can be limited by the allowed maximum pulling tension of the cables. 7 For large diameter cables, conduit fill is a factor of cable pulling tension. See pull tension information.
Pull Tension on Cables With the Use of Conduit
Conduit sizing is directly related to the planned diameter of the cable and the maximum pull tension that can be applied to the cable without degradation of the cable transmission properties. The pull tension limit is based on the strength of the conduit (including sidewall pressure), the strength of the pull line, the geometry of the conduit system, and the strength of the cable. The position of the bends and length of the conduit system will affect the pull tension that will be imposed on a cable. For instance, pulling cable in one direction may cause a cable pull tension of 2700 N (600 lbf) whereas pulling from the opposite direction may cause a tension of 1350 N (300 lbf). The pull tension of the planned cable to be installed needs to be calculated in both directions.
NOTE: Cable pulling tensions may be reduced by using lubricants that are specially formulated for the composition of the cable.
The following main contributory functions should be considered when calculating cable tensions. - The mass per unit length of cable. - The coefficient of friction between cable sheath and surfaces with which it will come in contact. - Deviations and inclinations.
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Layout
� – 33 Building pathways shall provide access to all Entrance Facility,, Equipment Room(s) and Telecommunications Room(s) located in the same building.
For instance, when a Telecommunications Room cannot be vertically stacked with the one above or below it, a pathway must be provided to link them. These pathways may be dedicated, or may be connected through a series of telecommunications spaces.
� – 34 Building pathways shall be configured to support a star cabling topology.
See the Telecommunications Room section of this manual for additional pathway recommendations for Telecommunications Rooms located on the same floor.
Location
� – 35 Pathways shall not be located in elevator (lift) shafts.
This requirement is provided due to the potentially detrimental effects of electromagnetic interference (EMI) in the shaft of an active elevator (lift). Additionally, the use of such pathways may be in violation of applicable codes and regulations. This requirement is made to allow Backbone pathways and cables to be serviced with minimal occupant disruption.
Size
� – 14 Sizing of Backbone pathways between building spaces containing cross-connect facilities should be sized based on a minimum of three, 100 mm (4 in) conduits. When the quantity of Backbone cabling exceeds more than one row of sleeves, designers should restrict the number of rows to two (2).
Provisions for Cable Installation
� – 15 When rooms are aligned with a common vertical pathway, some means for cable pulling, such as a steel anchor pulling iron or eye embedded in the concrete, should be provided above and in-line with the sleeves or slots at the uppermost room of each vertical stack. Similar techniques may be required for long Horizontal pathways.
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Campus Pathways
Campus pathways interconnect separate buildings such as in campus environments. These consist of underground, buried, aerial, and tunnel pathways.
� – 16 It is recommended that a telecommunications design plan be developed for all buildings, and the pathways between buildings, identified on the initial plot plan.
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Layout
� – 36 Campus pathways shall be provided between buildings served by the same Campus Distributor/Main Cross-connect.
These pathways may be aerial or underground, and may be connected through a series of telecommunications spaces. The figure shown below shows a typical configuration of campus pathways in a campus environment.
Typical Campus Backbone Pathway Scheme
Design
� – 37 Campus pathway design is outside the scope of the Siemon Cabling System, however, requirements involving the media choices length and bend radii limitations shall be met.
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NORMATIVE SUMMARY
Backbone Cabling
� – 1 To avoid problems caused by electromagnetic emissions from power cables and from premises equipment, the requirements of Annex B section of this manual shall be met for all Backbone cabling and pathways.
� – 2 The Backbone cabling shall use the conventional hierarchical star topology.
� – 3 There shall be no more than two subsystems of cross-connects in the Backbone cabling. From the Floor Distributor/Horizontal Cross-connect, no more than one cross-connect shall be passed through to reach the Campus Distributor/Main Cross-connect.
� – 4 Cross-connections shall be used for connections between Horizontal and Backbone cabling, between first level Backbone and second level Backbone cabling and for connections between Backbone cabling and premises equipment with multiple port outputs (such as 25-pair connectors)
� – 5 Connecting hardware shall not be installed in locations that are not specifically intended for telecommunications use which may violate applicable codes and regulations.
� – 6 All devices that are specifically intended to support a given application shall be installed external to the Campus Distributor/Main Cross-connect or Building Distributor/Intermediate Cross-connect.
� – 7 Bridged taps shall not be used as part of the Backbone cabling.
� – 8 When used, UTP and optical fiber splices shall be kept accessible and shall not be used for routine cabling system changes.
� – 9 Splices shall not be used on F/UTP and S/FTP cables.
� – 10 Where UTP copper cable is used in the Backbone (campus Backbone and building Backbone), the number of splices shall be kept to the minimum required by the physical system design or installation constraints.
� – 11 When used, splices shall be constructed using insulation-displacement type connectors and housed in enclosures appropriate for the environment.
� – 12 Optical fiber splices used in the Backbone shall be limited to an acceptable number which is based on an acceptable link attenuation budget.
Siemon Cabling System Training Manual IS-1821-01 Rev. M 5-27
� – 13 Multi-pair cable(s) used in the Backbone are intended to support voice applications only, and shall be tested for continuity.
� – 14 Balanced twisted-pair cables shall be Qualified Cables for use in the Siemon Cabling System. Refer to Allied Website @ www.siemon.com/allyfor Qualified Cables.
� – 15 Multimode and singlemode optical fiber cables shall be Qualified Cables for use in the Siemon Cabling System. Refer to Allied Website @ www.siemon.com/ally for Qualified Cables.
� – 16 All connecting hardware used with 100 Ω balanced twisted-pair cables and all connecting hardware used with optical fiber cables shall be provided by Siemon.
� – 17 All patch cords and equipment cables used to cross-connect or interconnect 100 Ω balanced twisted-pair, 62.5/125 µm and 50/125 µm multimode and singlemode optical fiber cabling for use in a channel model warranty, shall be manufactured by Siemon to receive applications assurance. For field terminated cable assemblies see note below.
� – 18 For each building Backbone subsystem that is greater than 90 m (295 ft) in length, optical fiber cable shall be provided if support for data applications is required.
� – 19 If the building Backbone run is less than or equal to 90 m (295 ft) in length, and optical fiber is not installed, category 5e or higher Backbone cable shall be provided if support for data applications is required.
� – 20 For each campus Backbone run, optical fiber cable shall be provided if support for data applications is required.
�– 21 The total channel length between the Campus Distributor/Main Cross-connect and any Floor Distributor/Horizontal Cross-connect shall not exceed the following length limits:
• 3,000 m (9,840 ft) for singlemode (OS1) optical fiber,
• 2,000 m (6,560 ft) for 62.5/125 µm or 50/125 µm multimode (OM1-OM3) optical fiber,
• 2,000 m (6,560 ft) for balanced twisted-pair for PBX/Class A (100 kHz) applications
• 200 m (656 ft) f for balanced twisted-pair for Class B (≤ 1 MHz) applications.
For data Class C, D, E and F (1-600 MHz) applications over copper:• 100 m (328 ft) for balanced twisted-pair (per Backbone segment when
5-28 Siemon Cabling System Training Manual IS-1821-01 Rev. M
� – 22 The total combined length of category 5e and higher balanced twisted-pair cross-connect jumpers/patch cords and equipment cables in a channel shall be determined by the following formula:
C = 102*- B(1 + D)
C = Combined length of patch cords/jumpers and equipment cables on both ends of a Backbone channel
B = Length of fixed Backbone cableD = .2 for UTP; .5 for shielded systems* ISO uses 105 for 5e. We have chosen to be more stringent to provide
better channel performance. This also allows for formula consistency.
For balanced twisted-pair if the formula is not utilized, the total combined length of cross-connect jumpers/patch cords between the CD/MC and BD/IC, or BD/IC and FD/HC, or CD/MC and FD/HC, and equipment cables shall not exceed 15 m (50 ft) in length if the Backbone channel is:• ≤100 m (328 ft) for balanced twisted-pair and applications assurance is desired.
Example: If the length of the fixed UTP cabling (CD/MC to FD/HC) is 85 m (278 ft) long, then the combined length (both ends) of equipment cables and cross-connections may be up to 14 m (46 ft) long. However, if the length of the fixed cabling is 90 m (295 ft) long, then the combined length (both ends) of equipment cables and cross-connections may be up to only 10 m (33 ft) long.
� – 23 The installation practices specified in the Installation Practices section of this manual shall be followed.
� – 24 Grounding/Earthing and bonding requirements specified in the applicable codes and regulations shall be met.
� – 25 Backbone pathways shall be designed and installed to meet all applicable local and national building and electrical codes.
� – 26 The quantity, size and bend radius requirements of Backbone cables shall be known to determine the type and size of the Backbone pathway. An allowance for growth shall be provided.
� – 27 Grounding/Earthing and Bonding of Backbone pathways shall comply with all applicable codes and regulations.
� – 28 Properly designed firestop systems shall be installed to prevent or retard the spread of fire, smoke, water, and gases through the building. This requirement applies to openings designed for telecommunications use that may or may not be penetrated by cables, wires, and raceways. Such systems shall comply with all applicable National and local fire protection codes.
Siemon Cabling System Training Manual IS-1821-01 Rev. M 5-29
� – 29 Pathways shall be suitable for the environment in which they are installed and shall not be impeded by HVAC Ducts, electrical power distribution, or surrounding building space limitations.
� – 30 Backbone pathways shall be installed or selected such that the minimum bend radius of Backbone cables is kept within manufacturer specifications both during and after installation.
� – 31 A defined telecommunications cable pathway (i.e., A pathway that is specifically dedicated for telecommunications use), shall be used for cable management.
� – 32 Building pathway types used for Backbone cables which have similar design and type as Horizontal pathways shall comply with the requirements of the Horizontal section of this manual.
� – 33 Building pathways shall provide access to all Entrance Facility(ies), Equipment Room(s) and Telecommunications Room(s) located in the same building.
� – 34 Building pathways shall be configured to support a star cabling topology.
� – 35 Pathways shall not be located in elevator (lift) shafts.
� – 36 Campus pathways shall be provided between buildings served by the same Campus Distributor/Main Cross-connect.
� – 37 Campus pathway design is outside the scope of the Siemon Cabling System, however, requirements involving the media choices and length limitations and bend radii shall be met.
