Information Technology Reference
In-Depth Information
nate another wire. Neglected trimmings will also make wire verification and tracing
more difficult.
The requirements of TIA-568-C dictate a minimum bending radius of four
times the cable diameter for certain categories of operation.
The time-honored technique of pulling the station cable very tight and bending
it back to the block before terminating the wires will have to be abandoned. You
should leave the cable somewhat loose if you are trying to maintain this minimum
bend radius. Many newer types of connecting blocks have wire management path-
ways, clips, ties, and other devices to prevent sharp bends in the cables. If your ter-
mination blocks do not have these accessories, you will need to use good habits
when you terminate cables to avoid problems. Remember that these guidelines also
apply to cross-connect cable and patch cords. Pair twist must be maintained and the
bend radius guidelines observed to maintain maximum rated cable link perform-
ance. A summary of workmanship and installation rules is shown in Table 7.1.
TABLE 7.1
Typical Workmanship and Installation Rules in the Standard
Document
Reference
Rule
Measure
Applicable to:
TIA/EIA-568-B
10.2.3
Terminate w/connecting
Horizontal cables
hardware of same
of higher category
10.2.3*
Minimum amount of
13 mm (0.5 in)
Cat 5
untwist at termination,
for 100-ohm cable:
Minimum amount of
75 mm (3.0 in)
Cat 3
untwist at termination,
for 100-ohm cable:
10.2.2
Maximum pulling tension 110 N (25-lbf)
4-pair UTP
10.2.1
Minimum bend radius
4
the cable
4-pair UTP
diameter
4-pair ScTP
†
8
the cable
diameter
*Mandatory requirement.
†
ScTP = screened twisted pair.
