Structured Wiring

This page shares some technologies and techniques about installing structured wiring. Structured wiring is a methodology for preparing a residence or business for telecommunications services. By standardizing the wiring, various technologies can be deployed without expensive re-wiring. Businesses began adopting structured wiring practices in about 1985. It has not been as popular in residences but is becoming more common with the growth of broadband Internet service and home theaters. Pre-wiring a house during construction is the easiest but it can be added to an existing home.

Structured wiring is all about the cable, how it is installed and how it is terminated. Some new houses built as late as 2006 have been wired with two pair telephone wire, daisy chained through each telephone location. This is very inexpensive at the time of construction but can be very expensive if the homeowner wants to connect computers or add multiple telephone lines. If revisions are needed, more wire will have to be installed at great cost. 

Structured wiring guides the installation to have a central termination area called the cross-connect. This is where all the cables will terminate for the various uses. The cabling is then installed in the horizontal run to the various outlets where the services are needed or might be needed in the future. The horizontal installation is done carefully, without damaging, kinking or stretching the cable. The outlets are installed in low voltage electrical boxes that maintain the bend radius of the cable and provide an in-expensive way to terminate.

Structured wiring can be used for computer networks (Ethernet), telephones (analog and Internet protocol), television signals (CATV, antenna, satellite), status monitoring and almost any other low voltage, low Wattage signals. The primary cabling in a residential structured wiring installation is Category 5e or Category 6 unshielded twisted pair (UTP). Telephone wire has evolved into a high bandwidth cable. Category 5e cable is adequate for computer networks up to 1000 Meg-bits-per-second (Mbps). 1000 Mbps is equal to one Giga-bit-per-second (Gbps). It is also excellent for traditional analog telephones and can be used to transport S-video television signals. With some limitations it can adequately transport home theater audio signals. Recent power over Ethernet standards have enabled remote powering of network devices on the same cable.

The other cable used in residential structured wiring is quad-shielded RG-6 coaxial cable. This is used to transport TV antenna, CATV and satellite signals. Strict structured wiring guidelines from BICSI (registered trademark) call for one or two RG-6 cables at each Category 5e location. This may not be required in all homes. Concentrating the coax cable at the known TV locations will reduce costs of the project.

Network cables are still a valuable infrastructure in the house even in this day of wireless technologies. Wired network bandwidth and reliability cannot be matched.  Our house uses three wireless access points but also uses about 30 wired Ethernet ports. With three laptops, two servers, five IP telephones, three TiVos and four  network cameras wireless was not adequate.

We recently had a new house built and during construction prepared for the structured wiring.

Preparation

Decide where you need wiring. Where you need telephones, where you need computer connections and where you need TV connections. Plan to install  two computer jacks (Category 5e) at each location because its just as easy to run two cables as one. You will need one or more coax cables at each  TV location. It will depend on your TV system. Do you need local antenna, CATV and/or satellite? I recommend 4 coax cables to your primary TV location and  one to other locations such as bedrooms. I also recommend four Category 5e jacks at the main TV location.

Cross Connect

• Shopping List

• Wall mount Ethernet switch
• Server racks
• 3/4" plywood backboard
• 2" stubs hold lots of cables
• 110 blocks more flexible
• punch downs (110 blocks)
• attic and crawl space/basement access

Cable

Always pull at least two Category 5e cables to each outlet location. Buy two boxes of cable so the two cables can be pulled at the same time. Locate the cable  boxes at the cross connect and pull from there to the outlet.

Install cable hangers on the floor joist or rafters to provide a pathway for the cables. Install the hangers on every-other joist or on about 32" centers. Use one  screw on the conduit straps when using them for hangers. That leaves one side of the hanger loose to add more cables. It should be practical to pull 100 feet of cable through a series of well placed conduit hangers.

An inexpensive cable hanger is a metal 3/4" conduit strap. They are only a few cents apiece. Near the cross connect larger conduit straps will be needed. Some home supply stores have plastic J hooks designed for pipe hangers that also work well for cable hangers. The J hooks can be found in the copper pipe supply area.

Unshielded Twisted Pair cable must not be damaged during installation. The high bandwidth characteristics can be damaged by kinks, tears, pulls, staples and tight bends. No bend should be less than a 1" radius. Staples must not be used unless they include a rigid standoff so the cable is not deformed. It is still risky to use staples because it is so easy to accidentally pierce the cable or hit the cable with a hammer. Loose hangers and Velcro binding is the safest method to secure the UTP cable.

• Shopping List

• Category 5e or Category 6 cable - 1000 foot box
• Quad-shield coaxial cable - 500 foot spool
• 3/4" conduit hangers for cable hangers
• J hook pipe hangers for cable hangers
• Velcro straps

Outlets

The introduction of open-backed low voltage electrical boxes simplified the structured wiring outlet installations. Carlon Structured Cabling products include an excellent old work low-voltage bracket. Their newest product the SC100RR is a low profile mounting bracket that installs easily because it includes built-in marking holes and straight edges.

• Shopping List

• nail guards
• with RJ-45 UTP connectors or coax F connectors.
• jacks (Leviton available at Home Depot) Decora or standard
• wall plates standard, medium or jumbo
• drills
• conduit stubs blue or orange flex
• low voltage boxes prefer Carlon old work style or hometech
• old work vs new work
• new work during construction after electrical