•
Use cable routing accessories designed to maintain and secure cable.
•
Leave enough slack in cables for operation of articulated arms and rail slides.
Since actual conductor size and type vary among types of cables, the bend radius rule can differ
among cable types. For example, Table 1 lists the minimum bend radius for HP fiber optic cables and
HP InfiniBand cables.
Table 1
. Bend radius for HP cables
Cable type
Minimum bend radius (R, R1, or R2)
HP LC-Type fiber optic
R = 0.8in (~2cm)
HP SC-Type fiber optic
R =1in (~3cm)
HP InfiniBand 4xcable
R1 = 4.6in (12cm)
R2 = 2.3in (6cm)
Note
The bend radius restrictions on some cable types, such as
InfiniBand cable, vary depending upon connector proximity.
For other cables, HP recommends that users refer to cable
specifications or contact the cable supplier for more
information.
Excessive bending of cables can create one or more of the following problems:
•
For power cables, stressed insulators or arcing across conductors
•
For copper data cables, stressed terminators, stress on center conductors, or disturbed twists on
conductors that increase sensitivity to noise
•
For fiber optic cables, micro-bending of fibers that results in degradation of light transmission or
breaking of fibers, which results in loss of signal
Thermal issues with cable routing
HP rack-mountable products that use forced-air cooling typically draw cool air through the front of the
chassis and push warm air out the back. If this air flow is restricted in any way, component
temperatures can rise, resulting in unscheduled system downtime due to thermal shutdown or damage.
For safe and reliable operation, ventilation slots and blowers at the rear of products must not be
obstructed by any components, including cables. Therefore, for proper cooling of rack-mounted
components, ensure that cabling does not impede the airflow to or from the rack-mountable servers.
Routing fiber optic cable
Fiber optic cable is lighter than copper cable; but it is relatively delicate, must be handled carefully
during installation, and may require extra protection. Damaged fiber optic cable poses no safety
hazards but can result in degraded or interrupted performance. HP recommends the following
guidelines for installing fiber optic cable:
•
Use only Velcro ties to reduce the chance of damaging cable from over-cinching or accidental
cutting.
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