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Appendix B: Cabling Recommendations
During installation, route cable bundles upward or downward along the sides of the rack depending on the actual situation
in the equipment room. All cable connectors should be placed at the bottom of the cabinet rather than be exposed outside
of the cabinet. Power cords should be routed upward or downward beside the cabinet close to the location of the DC
power distribution cabinet, AC power outlet, or lightning protection box.
Required Minimum Cable Bend Radius
The minimum bend radius of a power, communication or flat cable should be 5 times the overall diameter of the
cable. If the cable is constantly bent, plugged or unplugged, the bend radius should be 7 times the overall diameter.
The minimum bend radius of a coaxial cable should be 7 times the overall diameter of the cable. If the cable is
constantly bent, plugged or unplugged, the bend radius should be 10 times the overall diameter.
The minimum bend radius of a high-speed cable, such as an SFP+ cable should be 5 times the overall diameter of
the cable. If the cable is constantly bent, plugged or unplugged, the bend radius should be 10 times the overall
diameter.
Precautions for Cable Bundling
Before bundling cables, correctly mark labels and stick the labels to cables where appropriate.
Cables should be neatly and properly bundled, as shown in Figure B-1.
Figure B-1 Bundling Cables
Route and bundle power, signal, ground cables separately. When the cables are close to each other, cross them.
When power cables run parallel to signal cables, the distance between them must be greater than 30 mm.
All cable trays and their accessories shall be smooth and free from sharp edges.
Holes in metal, through which cables pass shall have smooth, well-rounded surfaces or be protected with insulating
bushings.
Use proper cable ties to bind cables together. Do not tie two or more cable ties to bind cables.
Cut off excess cable tie cleanly with no sharp edges after bundling cables, as shown in Figure B-2.
Figure B-2 Cutting off Excess Cable Tie