Installation manual

8-9
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© Copyright 2001 Leviton Manufacturing Co., Inc.
8
PRE-WIRE
Installation,
Labeling and
Documentation
Pre-Wire
Installation
A single low-voltage cable running through a stud hole
is unlikely to get damaged by a drywall nail or screw,
but a bundle of cables would certainly be subject to
damage. For the cost of some nailing plates, the nui-
sance and expense of replacing a damaged low-volt-
age wire inside a finished wall can be avoided.
It is especially important on vertical runs between wall
studs that bundles of low-voltage cable be secured
with Velcro® straps such as Leviton’s SoftCinch™.
When in doubt, you can never go wrong adding more
support in the form of:
• J-hooks and similar cable supports
• Cable clamps
• Velcro® wraps and straps
Installer’s Tip: The NEC calls for the distance between
an electrical box and the first strap or staple securing
AC cable to not exceed 12 inches. This rule does not
apply to low-voltage wiring and in fact would prevent
you from leaving a service loop securely tucked inside
of a wall.
8.4.3 Cable Bend Radius
Low-voltage cable is not as physically hardy as heavier
AC cable. 12/2 romex, for instance, can be bent at
much sharper angles without hindering its perform-
ance than can any low-voltage cable. TIA/EIA-570-A
(sections 8.2.1 and 8.4.1) sets out a very specific
bending radius for UTP cable and coax cable.
Essentially, they state that you should avoid sharp or
right angles and make as sweeping a bend as you rea-
sonably can with either of these cables. The cable
bend radius for Category 5 or 5e cable must not be
less than 4x the cable diameter or about 1-inch. The
bend radius for RG-6 quad shield coax must not be
less than 10x the cable diameter, or about 3-inches.
The bend radius for fiber cable must not be less than
10x the cable diameter. These sweeps should be main-
tained both in your cable runs and at termination.
Note: When pulling Coaxial or Optical fiber cable, main-
tain a minimum bend radius of 10x the cable diameter
or about 3 inches.
8.4.4 Service Loops
Mud ring installation gives the installer access to the
stud space. This in turn allows for a service loop, or
extra cable, to be stored in the wall and made available
in the event of:
• Damage to the wire at its termination
• A change of devices
• Errors when installing a jack
Leviton recommends:
• A 24-inch minimum service loop for Category 5 or 5e,
RG-6 quad shield coax, and speaker wire
• A 36-inch minimum service loop for fiber cable
• Make sure the service loops are larger than the mini-
mum bend radius for each type of cable (Category 5
or 5e: 4x, RG-6 and Optical fiber: 10x)
8.4.5 Labeling
It is critical that low-voltage cable be properly labeled.
The last thing an installer wants is to trace an errant
connection or incorrectly placed wire because it isn’t
identified or identified properly. Good labeling will
include:
• A master list or index of all cables
• A letter or number system for identification
• A label on both ends of all cables
Installer’s Tip: One method for cutting down the confu-
sion of multiple Category 5 or 5e cables is to use one
color of sheathing for your phone system and a sec-
ond color for data and networking. The cable is all the
same, but two different colors (say, blue and gray)
make it easier to keep track.
8.4.6 Label Placement
Labels should be placed near to the termination point
but far enough from the end to remain readable after
termination. The label should clearly identify each pair
of twisted cable, for instance, and stay clear of the
Category 5 or 5e jacks. Attaching a label to each end
of the cable, both at the SMC and behind the
wallplates, will greatly simplify identification later. Either
write your numbers or letters clearly in permanent ink
or, affix pre-printed labels. Computer-generated labels
Don’t allow cable to form right
angles or sharp bends
Use sweeping bends