CABLING SYSTEM INSTALLATION

Installation Quality

• The quality of installation is the most serious problem in implementation of the telecommunications cabling systems designed for the high-speed applications support

• There is a special system of requirements and conditionsto the installation of the cabling systems to preservethe primary transmission characteristics of individual components within the links, channels, and systems

• Whereas the rules of installation are the methods and accuracy of the component connections and cable organization and routing, the cabling rules are an important factor of the system capacity, simplifying the operationof the installed cabling systems

Installation Quality

• Significant reduction of the signal distortion may be achieved by the observance of the following requirements:

– Usage of special methods of the cable preparation

– Termination of the transmission media at the connecting hardware according to the manufacturer’s instructions

– Ordered arrangement of the cable bundles

– Correct spatial orientation of the connecting hardware

– Observance of the installation rules and manufacturer’s requirements to the installation of the telecommunications connecting hardware.

CABLE INSTALLATION

Cable Installation

6 Cable ties applied to form cable bundles shall be loose enough to allow the cable tie to slide around and along the cable bundle.

The cable ties shall not be tighten so snugly as to deform the cable sheath

Minimum Bend Radius

• The small bend radii are to be maintained for the twisted-pair cable because of the deformation and inconsistenciesof the transmission media inside of the cable occurringat the pair kinks

• This causes a serious deterioration of such parameteras NEXT

• Any attempts of bend straightening may be ineffectivefor the pair shape restoration and may have even worse effect

Minimum Bend Radius

• In case of the optical fiber cables, if their bend radius is under permissible value, it may increase the losses incurred owing to the macro- and microbends and even the fiber fractures

Minimum Bend Radius

• Illustration of the “minimum permissible cable bend radius” notion

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In this case minimum bend radius rule is not applicable

Minimum Bend Radius

10 The minimum Horizontal and Backbone subsystem cable bend radii shall be:Twisted pair (4 pairs):• 4 times the cable outside diameter – during installation• 4 times the cable outside diameter – after installation

Twisted pair (multipair):• 15 times the cable outside diameter – during

installation• 10 times the cable outside diameter – after installation

continued on next slide

Minimum Bend Radius

10 Optical fiber:

• 50 mm (2 in) for 2- and 4-fiber inside plant optical fiber cable, during installation

• 25 mm (1 in) for 2- and 4-fiber inside plant optical fiber cable, after installation

• 20 times the cable outside diameter for inside and outside plant optical fiber cable with more than

4 fibers, during installation

• 10 times the cable outside diameter for inside and outside plant optical fiber cable with more than

4 fibers, after installation

continued on next slide

Minimum Bend Radius

10 If the manufacturer’s requirements to the minimum bend radius of the certain cable are stricter than those specified above, the manufacturer’s requirements shall be observed

Minimum Bend Radius

1The minimum recommended bend radius forthe equipment and patch cables (cords) in service should be:

– 4-pair unscreened and screened twisted-pair cords –4 outside cable diameters

– optical fiber cords – 25 mm (1 in)

To observe these requirements it is recommendedto use specially designed means and devices

Maximum Pulling Tension

• On the cable installation and in some cases in their service (vertical segments) they are affected by the tensile load causing the pair deformation in the twisted-pair cables and mechanical damage of fibers in the optical fiber cables

• Therefore one of the basic installation requirements together with the bend radius is observance of the maximum permissible tensile load of the cables

Maximum Pulling Tension

11 The tensile load of the cables within the Horizontal and Backbone subsystems during installation and in service shall not exceed:

– 4-pair unscreened and screened twisted-pair cables – 110 N (25 lbf)

– multipair twisted-pair cables – manufacturer’s specifications

continued on next slide

Maximum Pulling Tension

11

– 2- and 4-fiber inside plant optical fiber cables –220 N (50 lbf)

– inside plant optical fiber cables with more than 4 fibers – the manufacturer’s specifications

– inside and outside plant optical fiber cables withup to 12 fibers – 1,335 N (300 lbf)

– inside and outside plant optical fiber cables with more than 12 fibers – 2,670 N (600 lbf)

– outside plant optical fiber cables – 2,670 N (600 lbf)

continued on next slide

Maximum Pulling Tension

11

– drop cable installed by pulling – 1,335 N (300 lbf)

– directly buried, trenched or blown into ducts cables – 440 N (100 lbf)

If the manufacturer’s requirements to the maximum tensile load of the certain cable are stricter than those specified above, the manufacturer’s requirements shall be observed

Media Termination

12 To maintain the cable geometry, the cable sheathshall be removed only as much as requiredto terminate the cable pairs on the connecting hardware.

The connecting hardware manufacturer’s instructions for cable sheath strip-back shall be observed

Media Termination

13 When terminating cable on connecting hardware,the cable pair twists shall be maintained as close as possible to the termination point. The distance fromthe termination point to the nearest pair lay node may not exceed:

• 13 mm (1/2 in) – category 5e, 6, and 6a cables

• 75 mm (3 in) – category 3 cables

Media Termination

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