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Thermal issues with cable routing, Routing fiber optic cable – HP DVP 3040 User Manual

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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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