Work Area Outlets - LAN Wiring - page 150

Outlet jacks are often color-coordinated with the room decor, which is fine as
long as standard NEMA ® electrical colors are chosen. Nonstandard colors may
cause a clash with other electrical outlet plates and may be difficult to obtain. If the
electrical plates have already been selected, you should try to match those colors.
Modular outlet jacks offer a variety of colors for the modular inserts.
In theory, the color markings allow one to easily differentiate between, say,
voice and data jacks. However, there are really no universal standards for these col-
ors. What may seem to be a logical color choice to you could be the opposite of
what someone else might choose. You might simply want to leave all the colors the
same neutral color as the faceplate and differentiate the jack functions with the plate
markings. Alternatively, you may choose to leave the telephone connector neutral
and use a differing color for the LAN jack.
Workmanship
The subject of workmanship is particularly important with regard to jack termina-
tion. The higher categories of wiring have strict guidelines for the amount of untwist
that may be present at any point of termination.
When a pair of wires is untwisted, even slightly, it can cause a greater disrup-
tion to the high-bandwidth signal transmission than almost any other noncontinu-
ity defect. Furthermore, there are several points of unavoidable untwist in any cable
link, and the effects of untwist are somewhat additive. You should carefully inspect
at least a sampling of cable terminations to make sure they are done properly.
Figure 6.19 shows a sample of a cable link with one improperly untwisted con-
nector termination. You can see that there is a very large cable anomaly at approx-
imately 72 feet from the tester. This test link was made up with an intentional excess
untwist of 3/4 in at one of the connectors of the 1 ft patch cord. When you compare
the size of this anomaly to the other connectors (which are all properly made), you
can clearly see the reason we emphasize good workmanship. Patch cords are easy to
inspect visually, but your outlet jack wiring is hidden in the wall. Be sure that the
person who installs your wiring is properly trained to do these connections well, and
test each horizontal cable run with a cable scanner.
Another workmanship issue that affects station outlets is the amount of excess
cable that is left at the outlet. Standard practice is to leave no more than 18 in of
extra cable length in wiring the outlet. This distance is measured from the wall open-
ing to the jack before it is installed. Excess cable should be trimmed before the out-
let is terminated. You should leave a reasonable length of extra cable to simplify the
initial termination and any subsequent inspections or re-terminations of a cable run.