Structured Wiring Systems
Steven D. Shepard
July 1997

I think it was George Carlin who once said, "A house is just a box where you put all your stuff. When you go out and get more stuff you have to get a bigger box." It's true. We are stuffing more and more products, capability and complexity in the modern home.

Just think about the common electrical and electronic systems that can be found in most homes today. There are lighting systems, heating/air conditioning systems (HVAC), communication systems (telephones), sprinkler systems, security systems, computer and entertainment systems, doorbells, intercoms, control systems and the list goes on and on. Traditionally these systems have been discreet separate systems made by many different manufacturers, installed by several different vendors and operate independently and diversely. In the evolution of the home controls industry it has become obvious and necessary that these independent systems must be integrated for a more intelligent and coordinated operation of the home or office.

Most of these systems can now be joined electrically with a structured wiring system. Structured wiring systems are the wiring backbone of an intelligent building. Just like a body contains a brain and a network of nerves to send control signals to muscles, structured wiring systems can be considered the central nervous system of the home or office. In this article I want to list the basic and fundamental components of a structured wiring system and their specific purposes in the operation of the modern intelligent structure.

If you are already familiar with common electrical house wiring you know that power comes into a building from the outside. This power is distributed around the home from a central point. This point is often called a breaker box. This box is where the circuit breakers are located. Circuit breakers are just fancy switches installed to detect overcurrent conditions on the various wiring or circuit runs that are distributed throughout the home. A circuit breaker automatically opens an electrical circuit disconnecting power when there is a problem. The breaker box is a good idea and required safety feature. It is also an intelligent central distribution point for all our high voltage (110 Volts AC) wiring.

Structured wiring systems follow this common electrical wiring model. The first fundamental component is also a distribution panel (or server). The server serves as the building's central point for accepting input from various external electronic services such as telephone service, cable TV or satellite service. The server distributes these services as an output to distinct electrical, or in this case, electronic, circuits throughout the home. The server serves as the central distribution point for low voltage or no voltage wiring throughout the structure.

Ah, but there is a difference. Instead of power, electronic structured wiring systems also connect and network the various internal electronic services and systems. Here we can utilize a central distribution location or point for sprinkler, security, computer and entertainment, doorbells, intercoms, and automatic control systems. Like connecting the brain to the body, we then provide enhanced capabilities, intelligence, convenience and active energy savings capacity throughout the entire structure. With that kind of power a building comes alive! No longer standing silent and mute, the home becomes an active and a smart participant in the day to day operation of the structure.

In the past when an external service was connected to the home, typically the vendor supplying that service provided their own interface box which was attached to the home. As we continue to stuff more products and services in the home it can become necessary to dedicate an entire wall to receive all these different and ugly interface boxes. How does that look?

One convenience that structured wiring systems provide is the power to maintain control on the overall appearance of the home. We decide how external service will mate to our home and how it will look. How much more intelligent it is to provide a standard central point (server) to receive and distribute all these services. It requires much less hardware. It also makes for a much more attractive, cleaner, efficient, less expensive and space saving installation.

Unlike the breaker box the server can contain electronic intelligence. If required, the server can be outfitted with modems, video drivers , modulators or amplifiers, multi-media routers and data communication bridges and hubs providing true digital computer networking capability. Is this important? That depends. How many telephones or TVs do you have in your home? How many computers? How many times have you had to change their location or exchange information between them and the systems at your office? You do the math.

If the server does not contain a whole house controller then a home automation controller can be installed within close proximity. So can a security system controller, a sprinkler system controller and other controllers. Efficiency continues because we have all these systems located in one central location in the home or office. This makes the interfacing of these systems much easier. It requires shorter wire runs between them. In the case of modifications, changes or if repairs must be made later, this central locating makes these systems much easier to find, isolate and diagnose saving time and money. Are we getting the idea yet?

The next fundamental component of a structured wiring system is the most obvious. The wire. Wiring packages are readily available. In the last six months the various wire manufacturers, distributors and vendors have reassembled their existing wiring inventory and products into a new bundle. Most will jump up and down shouting loudly and debate the quality, shielding, and frequency range of their product. Pages of specifications are nice but with wiring the quality of the installation can often be more important than the quality of the product. It can ultimately determine the value of the product.

The basic residential structured wiring bundle will contain two strands of Category 5 four twisted pair wires. When installed correctly these strands can be used for telephone, data communications, or for low voltage control. It will also contain two strands of RG6 coaxial cable. The coax can be used for external and internal video and also used for low voltage based control systems. More advanced wiring systems will also provide two runs of fiber optics cabling for the ultimate capacity in distributing clean and fast video or data communications. While fiber service is not yet readily available from our external services it is just a matter of time. Why not be prepared?

The installation of this low voltage wiring bundle is quite different than that of common electrical wiring. In fact, one of the quickest ways to create a problem for yourself is to lay these low voltage wires right on top or run them down a wall next to high voltage wires. If you are not yet familiar with electric induction and electro-magnetic interference (EMI) this is the hard way to learn about this branch of electric theory. The likelihood that electrical noise, shadowing, disturbances and downright signal failures increase astronomically if low voltage wiring is run adjacent to motors or high voltage wiring. This problem can occur even if low voltage wire is shielded.

The current industry practice is to install low voltage wiring inside of plastic PVC pipe or conduit well away (at least 12") from high voltage wiring. This conduit makes wiring changes and additions much easier. The conduit also helps to prevent wire breaks and bends in excess of ninety degrees which is something to avoid when working with high speed data communications or fiber.

Another virtue that fiber optics offers is that it is not susceptible to EMI and electrical induction. In fact, fiber optics is not even low voltage wiring. It is no voltage wiring as fiber operates on light frequency. You would not do so, but fiber could be run through water with little or no performance losses. Copper conductors simply cannot make that claim.

There are some concerns which must be kept in mind when purchasing a structured wiring roll. The tensile strength, or the amount of pull that can be exerted on the wire before it damages or breaks is important. This is of particular concern if the wire runs are being stretched across a large structure. Even a home of only two thousand to three thousand square feet in size can require a mile of electrical cable. Romex electrical wire will tolerate high stress and pulling. Low voltage wiring bundles are not as sturdy and should be well sheathed or jacketed to tolerate such installation requirements.

Another concern is related to the amount of copper actually in the cable or wire. It has been a wire industry practice to make the copper gauge smaller and lighter in order to decrease costs and increase profits. Make sure the wire insulation strips well and actually leaves enough copper to terminate and apply a connector.

The last fundamental component of a structured wiring system is the one that consumers and homeowners will see the most. It is becoming the icon used to identify the industry and the product. To your electrician this hardware fixture is called a drop or outlet. It looks for all the world like something similar to a common 110 Volt AC electrical outlet and it is that and more. In a structured wiring system this fixture is truly an electrical and electronic port with unique characteristics.

It is at this port where we the consumers attach the various appliances we use to make our homes entertaining, interesting and useful. The port contains an outlet providing automatically switched or controlled power. It provides a tap for the telephone receiver, TV, VCR, perhaps stereo speakers and computer all consolidated into one electric/electronic hardware fixture. Historically we required several different fixtures, outlets, plates, taps, hardware and holes in the wall to provide this much service. A single structured wiring port does all this and more using less hardware, taking up less space and at lower installation cost.

The fixture features the ability to accept Decora style inserts and plates of various colors to match interior decor. RJ45 telephone connector jacks are on board and can be used for telcom, data communications, infrared (IR) interfacing, or audio. The port coax connections (jacks) can be configured to provide external video services or simply provide a picture from a front door security camera. The port can be mixed and matched in any configuration from a single plate with few taps to triple or quadruple plates providing every electronic signal being distributed or generated within the structure. Configuration changes can be implemented quickly back at the server panel providing totally different and desired service at the port location of choice.

The typical installation will provide eight of these drops or ports in the main rooms of the home. More are available for larger homes and structures. Thought should be applied on the design so that wires are run to rooms that may require service in the future. Depending upon the manufacturer, the vendor performing the design and installation, and regional market conditions basic system costs start around $3000 and can easily go up from there. What must be remembered is that this system technology and installation replaces many traditional methods and products that we use in building. So not all of the structured wiring system costs should be calculated to add to existing costs.

Structured wiring systems are a product of the home controls industry that seem to be catching on. In fact, the indications are that builders will accept the idea of a structured wiring system long before they will a control system. This is not exactly where we thought the industry was going but that's OK. The most recognized manufacturers names at this time are AMP (also most expensive), IES, Mod-Tap, and USTec. Some of the national and local security companies are claiming to have their own designs (buyer beware).

Structured wiring systems ultimately provide a platform that will accept the intelligence and the technologies that implement automatic building control. The participants in the home control industry only need the qualifications, integrity and the right stuff to keep up with changes and the excitement of this industry in order to provide the right service to clients.

About the author: Steve Shepard is a partner in a small family business, SBT Automation. SBT Automation designs, sells, installs and services automatic control systems, fiber optic lighting systems and solar products and systems for residential and light commercial clients in the South Texas region. Mr. Shepard has been engaged in the automatic test and control industry since 1979 and can be contacted at (210)698-7109. Questions or comments concerning this article can be Emailed to sbtauto@juno.com

SBT AUTOMATION
25840 IH-10 West #4
Boerne, Texas 78006
(210) 698-7109
EMAIL: sbtauto@juno.com
URL: http://www.tristero.com/sbtauto/