136Appendix E Cable managementMismanagement of cable assemblies can lead to poor system performance, difficult maintenance,unscheduled downtime, and even safety hazards. This chapter describes proper methods andrecommended techniques for safe and effective cable management.PrerequisitesLabel cables before you route or bundle them. For more information about labeling cables, see thechapter ”Appendix F Engineering labels for cables.”Cable management guidelinesWhen you route and bundle up cables, follow these guidelines:• Bind and route the cables neatly inside the rack, and make sure that the cables are not kinked orbent.Figure 74 Correct and incorrect cable binding• The cable bend radius at connectors must be at least 5 times the cable diameter, and must be atleast twice the cable diameter away from the connectors.• Route different types of cables (for example, power cables, and signal cables) separately. If they areclose to one another, cross them over one another. If you route them in parallel, make sure that thespace between a power cable bundle and a signal cable bundle is at least 30 mm (1.18 in).• The cable management brackets and cable routing slots, inside or outside the rack, are smooth andhave no sharp edges or tips.• When you route cables through sharp sheet metal penetration points or along sharp edges ofmechanical parts, use bushings or take any other action to protect the cables from being cut orabraded. The sheet metal penetration points must be smooth and fully rounded.• Use the correct ties to bind the cables. Do not bind cables with joined ties. The following types ofties 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).
