| Home Toys Column - Apr99 - [HTI Home Page] |
HomeTech Hot Products Continuously Updated [Click Message To Learn More] |
Wiring outlets should not be placed in the same stud cavity as HVAC cold-air return ducts. Similarly, they should be at least one stud-cavity away from 120V/240V AC wiring. Ideally, all structured wiring should stay 12" from 120V wiring, and cross at right angles where necessary. |
Brian Karas is a Senior Network Support Engineer for the leading Frame Relay equipment provider by day, and a Home Automation and DataComm consultant and installer 'the rest of the time'. |
The next step is to determine how much cable will be needed, keep in mind this doesn't have to be a very accurate estimate, as most cable comes in 500'-1000' spools. Just multiply the total number of planned outlets by an average run length, add 5% for waste, and round up to the nearest 500 or 1000 foot mark. You'll typically find that buying in 1000' spools is the cheapest way to go, and with a 1000' spool of Cat5 running around $80 (including delivery) it's not very costly to err on the side of caution.
Before
the cable can be pulled, we'll need to drill some hole to pass the cables through, and
place our modified J-boxes or low-voltage brackets in the appropriate locations. I say
modified J-boxes because you'll want to cut the backs off of regular plastic boxes before
nailing them to the studs. This will keep your cables from getting kinked or severely bent
when the faceplates are installed. Cat5 and RG-6 have minimum bend radius' that must be
met in order to achieve peak performance. Sharp bends will degrade performance. If you
don't want to cut the backs off of the J-Boxes, you may be able to find low-voltage
brackets at your local home-improvement store, or on-line via mail-order sites like mine.
I still prefer the J-Boxes, they're cheaper, easier to find locally if you run out, and
the sides offer a little more protection and support to the faceplate and cables.
Whichever you choose, J-box or LV Bracket you'll want to make sure that they are the same height from the floor as the 120V work boxes that the electrician has placed. The best way to do this is to cut a scrap of wood to serve as a spacer for placing the boxes.
Nail the boxes, or brackets, securely to the studs.
You'll find the actual pulling of the cables will go faster if you can plan
their routes ahead of time, and pre-drill as many holes as possible. A long spade bit
works well for this, or a regular bit with an extension. This makes it easier to drill
holes overhead, or to drill floor holes without kneeling down. CAUTION: Always look at the
'other side' of the hole to make sure that you won't damage any existing pipes, wires,
ducts, etc! A 5/8" hole is usually sufficient to allow 2 Cat5 cables and 2 RG-6
cables to be easily pulled through. Space the holes about 2-3" from the stud, to
avoid hitting any nails or screws that have been used to build the framework.
Wiring outlets should not be placed in the same stud cavity as HVAC
cold-air return ducts. Similarly, they should be at least one stud-cavity away from
120V/240V AC wiring. Ideally, all structured wiring should stay 12" from 120V wiring,
and cross at right angles where necessary.
However, it is often
difficult to adhere 100% to this rule, try to maintain as much separation as reasonably
possible to minimize interference from the high voltage wiring. Sometimes, as you can see
from the following picture, you're left with no other choice. This outlet box was used as
a volume control, no interference is present in the finished job, but you don't want to
make this a habit.
Once you have your holes drilled, and the boxes mounted, you can begin to pull and secure the cables. It is often beneficial to have a helper on hand, however it is possible to do the job alone. Start by locating the cable boxes and spools at the wiring center location. To speed the process you'll want to pull several cables at once, typically you'll be pulling the standard 2 Cat5, 2 RG-6 bundle. I've found that it works best to buy the Cat5 in boxes, and the RG-6 in spools. The spools will require some sort of cable carrier to support them, this cable carrier can be easily made from scrap wood.
When pulling the cables take extra caution not to kink or snag the cables,
and don't pull them too fast, or else you may damage the jackets from friction and heat
buildup.
Once the cables have been run to the outlet box, you'll want to secure them at the box, and along their path, and then cut them off and label the bundle. A standard electricians staple can be used to secure the cables to the 2x4's. Be careful not to damage the cables from hammer blows, or by driving the staple too deep. You should be able to just barely pull the cables out of the staple, they should not be bound or 'stuck' behind the staple.
You may want to wait to secure the cables in the basement, or along
the main paths so that you can bundle the cable together into one large bunch, rather than
several smaller bunches. Depending on your layout, you may be best off using cable
hangers, available at most DIY centers, or on-line suppliers. These hangers can
accommodate up to 100 cables easily, and are typically hung from I-beams or joists.
Before you cut the cables from the spool, make sure you leave plenty of slack to allow the cables to be neatly routed in the wiring closet.
The last step in the cable pulling process is to firestop any holes
you drilled that pass between floors. A bit of insulation can be used for this, or
Firestop Caulk ($13.00/tube) made specifically for this task can be used instead.
Next month we'll cover the termination of the cables, and the installation of wiring
closet components.
© 1996 - 2010, Home Toys Inc. - All Rights Reserved
Powered by LJB Management Inc.