Contents

7 Appendix B  Cable management 7-1

General cabling requirements· 7-1

Cable binding guidelines· 7-1

Routing signal cables· 7-3

Routing power cords· 7-4

7 Appendix B  Cable management

General cabling requirements

Minimum curvature radius of cables

·     Attached power cord, communication cable, or ribbon cable—A minimum of five times the cable’s outer diameter. If the cable is frequently bent, connected and removed, the curvature radius must be a minimum of seven times the cable's outer diameter.

·     Ordinary attached coaxial cable—A minimum of seven times the cable's outer diameter. If the coaxial cable is frequently bent, connected and removed, the curvature radius must be a minimum of 10 times the cable's outer diameter.

·     High-speed cable (SFP+ cable for example)—A minimum of five times the cable's outer diameter. If the coaxial cable is frequently bent, plugged and unplugged, the curvature radius must be a minimum of 10 times the cable's outer diameter.

Minimum curvature radius of fibers

·     When the fiber is wrapped up around the cabling plate, the diameter of the cabling plate must be a minimum of 25 times the fiber's diameter.

·     When the fiber is being moved, the curvature radius of the fiber must be a minimum of 20 times the fiber's diameter.

·     When the fiber is attached, the curvature radius of the fiber must be a minimum of 10 times the fiber's diameter.

Cable binding guidelines

When you route and bundle up cables, follow these guidelines:

·     Label cables before you route or bundle them. For more information about labeling cables, see "Appendix E Engineering labels."

·     Bind and route the cables neatly inside the rack, and make sure they are not kinked or bent.

Figure7-1 Correct and incorrect cable binding

·     Route different types of cables (power cords and signal cables for example) separately. If they are close to one another, cross them over one another. If you route them in parallel, keep a minimum distance of 30 mm (1.18 in) between a power cord bundle and a signal cable bundle.

·     The cable management brackets and cable routing slots, inside or outside the rack, are smooth and do not have sharp edges or tips.

·     When you route cables through sharp sheet metal penetration points or along sharp edges of mechanical parts, use bushings or take any other action to protect the cables from being cut or abraded. The sheet metal penetration points must be smooth and fully rounded.

·     Use the correct type of ties to bind the cables. Do not bind cables with joined ties. The following types of ties are available: 100 × 2.5 mm (3.94 × 0.10 in), 150 × 3.6 mm (5.91 × 0.14 in), 300 × 3.6 mm (11.81 × 0.14 in), 530 × 9 mm (20.87 × 0.35 in), and 580 × 13 mm (22.83 × 0.51 in).

·     After binding the cables, cut the excess from the ties, leaving no sharp or angular tips. See Figure7-2.

Figure7-2 Cutting cable ties

·     When you bend cables, bind them as shown in Figure7-3. To avoid excessive stress causing cable core break, do not tie up the cables in the bending area.

Figure7-3 Binding cables where they must be bent

·     Route, bind, and attach excess cables for easy, safe maintenance activities and correct operations.

·     Do not tie power cords to slide rails.

·     When you connect a cable to an articulated part, for example, when you connect a grounding cable to a cabinet door, leave enough slack in cables and make sure they are not stressed from any movement of the part.

·     Cables must be protected at points where they might rub or come in contact with sharp edges or heated areas. Use high temperature cables near heat sources.

·     Securely fasten cables and take adequate measures to prevent loose connections.

Figure7-4 Securely fastening cables

·     Fasten heavy or rigid power cords at the connectors to relief stress.

·     Do not use tapping screws to fasten the connecting terminals.

·     Bind together cables that are the same type and routed in the same direction.

Table7-1 lists the cable bundling specifications.

Table7-1 Tie-binding parameters

·     Do not tie cables or bundles in a knot.

·     The metal parts of the crimped cold-pressed terminal blocks (such as circuit breaker) cannot protrude beyond the blocks.

Routing signal cables

The cable management brackets are installed along the left and right edges of the front panel. As a best practice, route signal cables along the cable management brackets as shown in Figure7-5.

Figure7-5 Routing signal cables

Routing power cords

The power supplies of the router are located along the left and right edges of the rear panel. As a best practice, route power cords as shown in Figure7-6.

Before routing power cords in the equipment room, consider the layout of the equipment room, including the locations of the power distribution box, AC power strips, and lighting protection box.

Figure7-6 Routing power cords