Home Technology Installation Basics

Home TechnologyInstallation Basics

■ Chapter 1 Wire and Cable Basics■ Chapter 2 Connector Types and Uses■ Chapter 3 Wiring Installation Practices■ Chapter 4 Codes, Standards, and Safety Practices

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CHAPTER 1Wire and Cable BasicsIn this chapter, you will learn about:

• Wire types, insulation and jacket materials• Cable types, construction, and characteristics• Cable performance, attenuation, cancellation, and interference

Just like a house is built on its foundation, a home automation network is built on its wir-ing. Home networks of all types, and yes, even wireless networks, are built on a networkof electrical, communications, and audio/visual wiring.

The myriad standards, guidelines, and cable and wire types can be a bit confusing,but when you organize them by the various systems in a house, it’s really not all thatcomplicated. This chapter focuses on the different cable types and their construction,performance, specifications, and how each is typically used in a home automationproject. A variety of different wire and cable is used in home electrical, audio, video, andcontrol systems. This chapter provides you with the basics on the wire or cable used ineach of these different applications in a home.

Electrical Wiring and CableResidential electrical wiring actually includes all of the wiring in a home, but for nowwe want to focus on the low voltage wiring. If you plan on using any of this wiring as acomponent of a home network, of any kind, it is important for this wiring to conform tocertain standards and codes.

Low Voltage versus High VoltageWhen installing wire and cable in a home, you must be aware of the voltage specifica-tion of the cable in use. There are certain cable types that are specified as low voltage andthose specified as high voltage. Low voltage cable is designed to carry lower levels ofalternating current (AC) and direct current (DC) voltages than is high voltage. I knowthat may sound like a no-brainer, but there is enough of a difference between these twocabling types that electricians are certified separately for installing one or the other.Table 1-1 lists the basic cable categories and the voltage range each is specified to carry.

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Low Voltage WiringNo specific definition exists for what is generally called low voltage wiring. In somereferences, low voltage is circuit wiring of less than 30 volts (V) of alternating current(AC) or 60V of direct current (DC). Another reference defines it as being less than 50VAC and yet another defines it as being between 0 and 150V AC and DC. In effect, theterm low voltage wiring, which typically is used to describe communications, speaker,security and control signal wiring, is more of a slang term than a specific reference. How-ever, in common usage, electricians use low voltage to refer to less than 50 volts and wiregauges less than 16 AWG.

Low voltage wiring is defined as being one of five types of circuits:

• Communication circuits These circuits carry data signals between devices,typically connected to a network of devices. Communication circuits, such asdata networking, telephone, and in some cases, electrical cabling, are explainedin detail in Chapters 3 and 10.

• Signal circuits A signal circuit is an electrical circuit that supplies power to anappliance or electrical device that produces a visual light signal or audible soundsignal. Examples of signals circuits are doorbells, buzzers, signal lights, fire orsmoke detectors, alarm systems, and other types of security systems.

• Remote control circuits A remote control circuit is an electrical circuit thatcontrols one or more other circuits, motor controllers, magnet contacts, orelectrical relays. A remote control circuit controls the supply of power to electricalequipment like appliances, lighting, and heating devices or provides commandsignals to control their operation.

• Motor control circuits A circuit that carries electric signals that control thefunction of a device or motor controller, but not the main electrical powerservice.

• Power-limited circuits Circuits that aren’t used for signaling or remote controlwhere the power on the line is limited are power-limited circuits. A low voltagelighting circuit that includes 120V to 12V transformers to drive 12V lamps is anexample of a power-limited circuit. Power-limited circuits are limited to 30V.

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Cable Type DC Voltage AC Voltage Usage

Extra Low Voltage (ELV) < 120 volts (V) < 50V Audio, video, telephone, data cables

Low Voltage 120V – 750V 50V – 500V Standard household electrical wiring

High Voltage > 1.5 kV > 1 kV Power lines to a home

Table 1-1 ELV, LV, and HV wiring and their voltage specifications



Low Voltage ClassesLow voltage circuits are divided into three circuit classes, as detailed in Table 1-2.

A few examples of Class 2 circuits are low voltage lighting control, thermostats, secu-rity systems, intercoms, audio systems, and computer networks. Some security systems,intercoms, and audio systems can also be Class 3 circuits. Each circuit class also definesthe cable class that must be used. On Class 2 and 3 circuits, the cable used must be ratedfor Class 2 and 3 circuits, respectively. The manufacturer’s specifications should indicatethe rating class of each cable it sells and the class rating should be marked on the cable asCL2 (Class 2) or CL3 (Class 3).

Electrical WiringGenerally, home automation projects rarely have to deal with electrical wiring, except toplug a controller or network adapter into an outlet. However, if you are installing home

Chapter 1: Wire and Cable Basics

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VoltagesThere are many voltage numbers around. You may read or hear about 110V, 117V,120V, 208V, 220V, or even 480V. Different countries or regions of the world havedifferent electrical systems and each electrical system may support a different voltage.

In North America, the electric companies supply a split-phase 240V feed, whichis two 120V (plus or minus 5V) feeds, to its residential and commercial customers.The wiring in each building has built-in resistance that can drop the voltage in theraw feed to 110V or 220V at the outlet. So, for all purposes, 110V is the same as 120V,regardless of how electrical devices or installation specification are labeled. If a prod-uct is labeled as 110V, it merely means that the product is capable of operating atelectrical levels as low as that.

However, 208V is not a reduction of 240V. This is the voltage of a 3-phase Y-circuitthat has 120V from any neutral to hot. The voltage of a 3-phase Y-circuit that runs277V from hot to neutral is 480V. However, most motors intended to run on 480Vare typically labeled as 440V. Confused? Don’t be. Home networking is mostly a 12and 24 volt environment.

Class Type Volts Volt-Amps (Power)

1 Power-limited, 30 1000

1 Remote control and signaling 600 No limits

2 DC 30 100

3 DC >30V >0.5, but not more than 100 VA

Table 1-2 Low voltage circuit classes



network wiring into open walls or retrofitting wiring into an existing wall, you shouldbe able to at least recognize common electrical service wiring and its characteristics.

NOTE Most of these electrical wire characteristics also are found in lowvoltage wiring as well.

The most common electrical wiring used in home construction today are

• Modern non-metallic (NM) This wire is made up of two solid copper oraluminum core wires insulated with plastic vinyl and a bare copper groundwire sheathed with a paper layer and an outer vinyl jacket. Modern NM wiringis flexible, durable, and moisture-resistant, which is why it is the most popularchoice for residential electric wiring. See Figure 1-1.

• Underground feeder (UF) This wire, which is also referred to as NMC cable,is very much like NM cable, except that the three copper wires (two insulatedand one bare) are embedded in solid plastic vinyl sheathing. UF wire is the bestchoice for damp or buried installations.

• Zip wire This wire type is lighter duty than most residential wiring and hasvery limited use. Most lamp cords are zip wire, which gets its name from thefact that the two conductors are molded together, but can be easily separated bypulling them apart manually. Figure 1-2 illustrates the composition of a zip wire.


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Voltages Around the WorldVoltage can have different values, especially when it comes to wiring ratingsand specifications. For example, common voltages used in wiring specificationsare 110V, 117V, 120V, 208V, 220V, and 480V. Different countries and world regionshave different electrical systems and each electrical system could specify and carrya different voltage than its neighboring countries.

In North America, the electric companies supply a split-phase 240V, 60 Hertz(Hz) feed, which is made up of two 120V (plus or minus 5V) feeds, to residentialand commercial customers. The wiring in each building has built-in resistance thatdrops the voltage of the raw feed down to 110V or 220V at the outlet. As a result,electrical service in North America is referred to as 110V (the net of the nominal120V feed) or 220V (net of nominal 240V).

In European countries, electricity is supplied at the nominal voltage of 220Vto 230V. Like electricity in North America, the actual voltage can vary by 10 percent.Some countries offer 110V at the outlet, but all European electricity is 50 Hz (aka 50cycles), and this difference is enough to require North American travelers to use aconverter, just like European travelers must do in North America.



Some older wire types you may encounter in a house ar

• Flexible armored cable This two-wire type of electric cable, which is alsocalled Greenfield or BX wire (see Figure 1-3), was very popular from the 1920sto the 1940s. The metallic armoring around the outside of the cable providesthe grounding.

• Metal conduit From the 1940s to the 1970s, two insulated wires were installedin rigid metal conduit tubing. The metal of the conduit provided the grounding.Metal conduit installation is still required in some areas for bare wire installationsin basements, foundation crawl space, attics, and garages. It is also required insome cities. Check your local codes.

• Early NM This two-wire cable was popular from the 1930s to the mid-1960s.It is made up of a flexible rubberized fabric jacket that surrounds two solid copperwires with rubber insulation and paper sheathing inside the outer jacket. EarlyNM wire had no grounding wire.

• Knob and tube Wires covered with a rubberized fabric material, called “loom,”was strung over ceramic insulators (knobs) and ceramic tubes through studsand joists (see Figure 1-4). This is a very old and obsolete wiring system foundin homes constructed before 1940.


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Figure 1-1The constructionof modern non-metallic electrical

Figure 1-2The makeupof zip wire



Residential Wire Gauge and CharacteristicsThe wire gauge used in a home depends on the number of amperes on a particular cir-cuit. For example, if a circuit has 20 amps, a 12-gauge wire should be used. See Table 1-3for a listing of a few of the common circuit amps and the appropriate wire gauge to use.Remember that a smaller gauge means a bigger and less flexible wire. For wire runslonger than 100 feet, or placed inside a conduit, or installed in a bundle with other wires,the next heavier gauge wire should be used to avoid voltage drops and to overcome heatproblems.


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Figure 1-3BX cable is a typeof armored cable.

Figure 1-4Knob and tubeinsulators wereused in homesbuilt before 1940.

Photo courtesy ofMarkus Burns.



Twisted-Pair CableTwisted-pair wiring is by far the most popular installed media for networking in justabout any type of network for many reasons, including that it is inexpensive, easy tohandle, and readily available. Twisted-pair (TP) wire is the de facto standard for bothEthernet and Token Ring networks.

Twisted-pair wire gets its name from its construction. Pairs of 24-gauge (or heavier)wire are twisted around each other to reduce the impact of cancellation betweenthe two wires. Two types of twisted-pair wire are available: unshielded and shielded. Un-shielded twisted-pair (UTP) wire, shown in Figure 1-5, doesn’t include any EMI shielding


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AWG/B&S* CSA Circuit Amps Ohms per 1K feet Common Usage

24 /Cat 5e 0.205 2.1 28.6 Communications

18 – 22 0.0480 – 0.0280 10 – 8 6.386 – 16.200 Thermostats,doorbells,security systems

16 0.051 12 4.016 Audio

14 0.0800 15 2.524 Light fixtures,receptacles

12 0.1040 20 1.619 Light fixtures,receptacles

10 0.1280 30 1.018 Air conditioner (AC),clothes dryer

8 0.1600 40 0.641 Electric range,central AC

6 0.1920 60 0.403 Central AC,electric furnace

Table 1-3 Wire Gauge to Circuit Amperes Chart* AWG stands for American Wire Gauge; B&S refers to Brown and Sharpe, whichis equivalent to AWG; and CSA refers to the Canadian Standards Association.

Figure 1-5The constructionof unshieldedtwisted-pair(UTP) wiring



to speak of, while shielded twisted-pair (STP) wire, shown in Figure 1-6, has an extrawrapping of foil to help protect the inner wires from EMI and cancellation effects.

UTP cable is designated for various usages through a wire category specification thatdivides the various grades of UTP into a series of categories. Each category, of the sevendefined to date, defines a specific number of wire pairs, a number of radial twists per foot(or twists per inch), the number of wire pairs, the bandwidth rating, the maximumsegment (run) length for performance, and its recommended networking usage. Table 1-5details the various UTP wire categories, which are referred to as “Cats.” The mostcommon cable categories used in structured wiring systems are Cat5, Cat5e, and Cat 6.

Twisted pair cable gets its name from its construction style. Most TP cables have mul-tiple pairs of wire, typically two or four pairs. Each wire pair is wrapped or twisted around


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AWG and Metric Wire SizesWire, including the wires bundled into a cable, is measured in a variety of sizesthroughout the world. In the U.S., wire is measured using the AWG or AmericanWire Gauge standard. AWG measures the diameter of the wire using a fairly com-plicated formula that boils down to for every 6 gauge decrease (say, from 24 AWGto 18 AWG), the diameter of the wire doubles in measurement.

Many countries around the world use metric wire gauges that states a wire gaugeas ten times the wire’s diameter in millimeters (mm). For example, a 40 gaugemetric wire is 4 mm in diameter. So, using the metric wire gauge system, as the wirediameter increases so does the wire gauge. This can cause some confusion betweenthe AWG system and the metric wire size system, so generally metric wire sizes arestated in millimeters and not as metric gauges. Table 1-4 shows a comparison ofAWG wire gauge and metric wire size of wires commonly used in structured wiringsystems.

AWG (in millimeters) Metric Wire Size

10 2.588

12 2.304

14 1.628

16 1.290

18 1.024

20 0.081

22 0.065

24 0.511

26 0.404

28 0.320

Table 1-4Comparison ofAWG gauge andMetric wire sizes



one another to help protect the wires from interference and crosstalk . The more twistsin the wires, the better the protection.

In North America, UTP is the most commonly used cable for low voltage (LV) instal-lations. However, outside of North America, shielded twisted-pair (STP), and its twovariations, screened twisted-pair (ScTP) and foil twisted pair (FTP) wiring (see Figure 1-7)are commonly used. ScTP and FTP include an overall shielding layer, but don’t provideas much protection from interference as STP.

UTP cable carries a variety of rating codes, which are assigned by the product perfor-mance and safety authorities and testing laboratories. The primary rating codes for UTPcable are defined by the NEC (National Electric Code), published by the National FireProtection Association. Table 1-6 lists the primary UTP cable ratings.


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Figure 1-6Shielded twisted-pair (STP) wiringhas a foil wrapperto protectit from EMI.

Category Bandwidth Wire PairsMaximumSegment Length Applications

Cat 1 128 Kbps 2 100 meters POTS, ISDN, door bell wiring,speaker wire

Cat 2 4 Mbps 4 100 meters Token Ring networks

Cat 3 10 Mbps 4 100 meters 10BaseT

Cat 4 10 – 16 Mbps 4 100 meters 10 Mbps Ethernet16 Mbps, Token Ring

Cat 5 100 Mbps 4 100 meters 100BaseT, ATM, CDDI

Cat 5E 200 Mbps 4 100 meters 1000BaseT

Cat 6 600 Mbps 4 100 meters CDDI, 1000BaseT

Cat 7 1 Gbps Undefined Multiple wire pairs witheach twist insulated

Table 1-5 ANSI/TIA/EIA UTP Cabling Standards



Coaxial CableCoaxial cable is constructed of a single inner core wire conductor that is encased in a layerof dielectric insulation, which is then wrapped by a wire mesh outer conductor and shield.A plastic sheathing covers the cable. Some manufacturers also add additional layers ofmesh or foil shielding between the mesh and the outer jacket. Figure 1-8 illustrates theconstruction of a coaxial cable.

Coaxial cable is called single-ended cable because it has a single signal path and asingle return path. The core wire carries the positive signals to the next device and thebraided mesh layer of the cable carries any return signals.

The different classes of coaxial cabling that are commonly used in residential systems are

• RG6 This type of coaxial cable is a 75-ohm cable commonly used with digitalsatellite systems, analog television, VCRs, CCTV, CATV. RG6 coaxial cable is theminimum requirement for many digital television systems and for televisionantenna system in multidwelling buildings. RG6 cables are typically terminatedwith F-type connectors.

• RG11 This type of coaxial cable is fairly stiff and difficult to work with. It wasonce fairly popular with Ethernet data networks and is included in the IEEE 802.3Ethernet specifications as 10Base2. RG11 coaxial cabling is most commonlyterminated with BNC connectors. This cable is occasionally used for long cableruns for digital television feeds.


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Figure 1-7Foil-wrappedtwisted paircabling (FTP)is commonlyused outsideof the U.S.

Photo courtesyof Berk-Tek.

Rating Description

CM General building cables suitable for non-plenum and riser application.

CMP Horizontal cabling that is suitable for installation in ducts and plenums without conduit.

CMR Riser (vertical) cabling that is suitable for use in vertical shaft installations.

Table 1-6 NEC cable ratings



• RG58 This type of low-loss coaxial cable is a 50-ohm cable with a diameter of0.195-inches that is a good general purpose cable commonly used for securitysystems and video display applications. RG 58 cables are commonly terminatedwith BNC connectors.

• RG59 This coaxial cable type is a low-loss 100-ohm cable with a diameter ofjust under 1/4-inch that is a general purpose cable that can carry about 20 percenthigher frequencies and a bit longer attenuation limit than RG58 cable. RG59cable is suitable for basic analog television antennas in homes and for CCTV onshort cable runs. RG59 cable is commonly terminated with F-type connectors.

Fiber Optic CableFiber optic cabling (see Figure 1-9) is certainly an option for installing a home network,but it’s not usually a particularly practical one. While fiber optic is extremely fast, it canbe difficult to work with, its interface devices are relatively expensive, and copper wiretechnologies have advanced to the point that they are capable of transmitting multipleCD- or DVD-quality streams simultaneously. Wiring with fiber optic cabling in home isgetting it ready for the future and probably won’t be connected and used at the time ofinstallation.

The fiber optic cabling used in home installations is typically multimode cable. Fiberoptic cable is either single-mode or multimode. Single-mode cable carries a singlesystem, but over very long distances. Multimode fiber optic cable is capable of carryingmultiple signals, but over a shorter distance, which are still far beyond the requirementsof just about any home.


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Figure 1-8The layers ofan RG6 coaxialcable

Figure 1-9A multi-strandfiber optic cable



Audio and Video Wire and CableIf you understand how water flows through a hose, then you essentially understand thephysics of how electrical waveforms travel through an audio/video cable. Just like a waterhose stores and releases water, when an audio signal is transmitted, the audio/videocable stores (voltage) and releases (current) an electrical wave at certain frequencies andamplitudes and are generally combined under the term frequency. An audio/videosignal consists of a collection of high and low frequency waves.

Another function of an audio/video cable is its ability to release or pass the audiosignal to the next component (amplifier, speaker, or the like) at the right time, withoutslowing down the signal. A cable with the ability to release the signal at the right time iscalled in-phase. Not all cables are able to efficiently carry (store and release) audio signalsat all frequencies. Virtually every audio cable can carry high frequencies (above 1 KHz)fairly efficiently. However, the ability for a cable to remain in-phase diminishes as thefrequencies drop below 450 Hz. When this happens, the lower frequencies are producedout-of-phase, or reproduced later than the higher frequencies.

Balanced Audio CablesA balanced audio cable uses both positive and negative carriers, like a coaxial cable, butthey also add a grounding carrier as well. In what I’ll call an unbalanced cable, the ground-ing signals are combined onto the negative carrier.

A balanced audio cable is used in high-end or professional microphone, line-levelbalanced analog audio, extended distance runs, and wiring interconnected to a patch panel,is made up of two twisted-pair insulated wires, commonly copper, and a separate ground-ing wire or mesh shield (see Figure 1-10).


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Frequency, Amplitude, and HertzNo, this isn’t the name of an audio industry law firm; these are the properties thatcharacterize the parts of an audio signal.

• Amplitude The height of an audio signal, which translates into the volumeof each part of the signal.

• Frequency The number of cycles (waves) for a sound in a second. Frequencytranslates to the pitch of a sound. Every sound has pitch, a tiny bell hashigh pitch and a high frequency, and a bass drum has low pitch and a lowfrequency. Frequency is measured in Hertz.

• Hertz The measurement of the number of cycles occurring in an audiowave in one second. One wave, measured from the center of the raise inamplitude to the center of the decline in amplitude is one Hertz, whichis named after Heinrich Hertz, the discoverer of this phenomenon.



Parallel Pair WiringThis type of wiring, which resembles lamp cord, is made up of two separate conductors(a positive and a negative) that are encased in a single plastic or rubber insulating jacket(see Figure 1-11). This type of wiring is inexpensive, but doesn’t provide much protec-tion from external interference. Parallel pair wiring is commonly referred to as speaker wire.

Parallel wire is available in a variety of wire gauges, ranging from 8-gauge on the high-end to 24-gauge on the low end. However, the gauge that should be used is dependenton a number of factors. A cable with conductors too thin for the signals generated by theamplifier will produce a degraded sound quality with loss in the lower frequencies. Incontrast, a cable that is too heavy may be too awkward to work with easily and will defi-nitely cost more.

CROSS-REFERENCE Chapters 15 and 16 discuss speaker and audio cablingin detail.

NOTE Speaker wire and parallel cable are often advertised as “oxygen-free.”What this means is that the cable has no corrosion. As a cable is exposed tothe air, it can begin to darken in color, which means it is oxidizing. In fact, if acopper wire is green, it is likely fully oxidized.


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Figure 1-10Samplesof balancedaudio cables

Photo courtesy of GepcoInternational, Inc.



Video Cables

There are a variety of cables that can be used with video systems. The primarytypes of video cable are

• Coaxial This cable is the standard used for cable television connections. Coaxialcable can be terminated with either a BNC or an RCA connector (see Chapter 2).Although it is developing other applications, such as transmission of IR signals,coaxial cable is used primarily for antenna and cable inputs and video distribution.

• Component (also called digital component) The newest of the cable andconnector types that provides the best picture quality. The video signal is separatedinto individual red, green, and blue (RGB) color components, which results inbetter color and clarity. The connection for a 3-channel component cable hasthree plugs, one for each color component. Component cable is available in 3, 4,or 5 channel (wire run) configurations. Figure 1-12 shows a component videocable with 4 coaxial cable channels.

• Composite A standard video signal format that contains the color, brightness,and synchronization information. Virtually all VCRs and other legacy videoequipment have a composite video input or output. Composite video cables area single cable carrying only the video signal component. Composite A/V cablesthat also carry the right and left channels of the audio are terminated with threeconnectors that are typically color coded with a yellow jack for the video, a whitejack for left-side audio, and a red jack for right-side audio. The jack and plugused for composite video are RCA connectors or F-type or BNC coaxial connectors.Figure 1-13 shows a terminated composite video cable.

Speaker WireThere are several types of speaker wire on the market. Typically, 16-gauge stranded twisted-pair wire or 14- to 18-gauge audio cable is used for an average length speaker run, with


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Figure 1-11Parallel pair wireis commonly usedfor speaker wire.

Figure 1-12A videocomponentcable withfour channels



heavier wiring used for very long runs. The twist in the wire helps reduce the amount ofEMI the wiring picks up.

The following terms are commonly used to describe speaker wire and its characteristics:

• Cable Ratings The cable designed for a specific use is rated for that use. Forexample, a cable designed for installation inside a wall carries a premise wiringrating. Most speaker cable is not premise wiring rated. Premise wiring rated cablecomplies with the National Electric Code (NEC) and provides assurance to youand your customer that the design of the cable meets fire safety standards as well.

• Gauge The wire gauge selected for a home A/V system should be chosen basedon its properties and the distance of the wiring runs. Speakers have low impedance(4 to 8 ohms), which means the resistance in the wiring is key to determininghow much of the audio signal will reach the speaker. For example, a 100-footrun of 16- gauge twisted pair wiring has a round-trip resistance of 0.8 ohms.When this wire is used with a 4-ohm speaker, 17 percent of the signal is lostto the resistance on the wire, which means only 83 percent of the sound signalactually reaches the speaker. The solution to this is the use of heavier wire. Thewire sizes typically used for home A/V systems are 16 or 14 AWG (AmericanWire Gauge), which provide good compromises against signal loss, cost, and easeof installation. On top of that, the connectors on most audio devices aredesigned for these wiring sizes.

• Signal (power) loss Table 1-7 lists the maximum cable run distances for 16-and 14-gauge speaker wiring given the percentage of power lost to the cabledue to line resistance. If you know the speaker’s impedance and acceptable lossnumbers, you should be able to look up the right size wire to use and its maximumrun length.


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Figure 1-13A compositevideo cableterminated withRCA connectors

Photo courtesy ofCanare Corporationof America.



Wire and Cable CharacteristicsAll wire has a number of performance properties and characteristics that limits the useof just any wire in any situation. The primary performance properties of metallic wire are

• Attenuation As an electrical signal moves through a wire, it eventually reachesa point where it begins to lose its strength—the attenuation point. Beyond thispoint, the signal may become distorted or lost altogether. Every cable type is ratedwith an attenuation distance, which indicates its maximum run length.

• Cancellation When two wires are not properly insulated or placed too closelytogether, the signal in one wire can be significantly impacted by the signal in theother wire. This is also referred to as phase cancellation.

• Crosstalk This condition is caused when the signal in one conductor, which isalso referred to as a channel, leaks into another channel and distorts its signal.

• Interference Electrical signals, in the form of electromagnetic (EM) or radiofrequency (RF) waves, can penetrate a cable and distort or disrupt the signalsbeing transmitted over the cable. The two most common types of interferenceare electromagnetic interference (EMI) and radio frequency interference (RFI).EMI is caused by strong electromagnetic fields emanating from nearby electricaldevices, such as electrical motors, magnetic ballasts, and the like. RFI is causedby radio frequency electromagnetic waves, like radio and TV signals, that travelthrough the air and are picked up by the conductors or shielding of a cable.

• Inductance Signals carried on a wire typically have a varying current thatproduces a varying magnetic field and can create additional current in the samecable or a nearby cable. In a TP cable, the wires in each wire pair are twisted aroundeach other to reduce electromagnetic induction between the wires.


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Speaker Ohms Decibel Loss Signal Loss16 AWGMax. Run (feet)

14 AWGMax. Run (feet)

4 0.5 11% 60 100

4 1 21% 130 210

4 2 37% 290 460

4 3 50% 500 790

8 0.5 11% 120 190

8 1 21% 260 410

8 2 37% 580 930

8 3 50% 990 1580

Table 1-7 Speaker Wire Signal (Power) Loss Table



Control WiringThere are many different types of control systems in an automated home: lighting control,climate control, security, and perhaps even water control (as in controlling the lawnsprinklers).

The wiring that supports and interlinks the control system’s elements is readily avail-able, inexpensive, and easily installed, especially in a new construction situation. Installingnew control system wiring in an existing house can be more difficult, but there are alter-natives to new wiring in these situations, such as powerline carrier (PLC) and phonelinesystems, discussed in Chapter 10.

NOTE Most control systems don’t require heavy duty wiring, generally only22-gauge wiring or Cat 3 UTP cable, at a minimum.

Bundled CableStructured wiring involves the installation of wire homeruns to each room, zone, or area ofa home. There are two ways this can be accomplished: pulling each individual cable re-quired separately or pulling in a cable bundle that includes all of the cabling runs requiredto support the needs of the room, zone, or area.

Using a structured cable bundle eliminates the guesswork of pulling individual ca-ble runs to areas of the home in attempts to provide future capability to the home. Acable bundle pulled throughout a home provides additional capability and expanda-bility to all areas of a home and can save on installation time.

Some cable bundles are enclosed inside a plastic outer sheathing to facilitate pullingthe cable through the walls. Others connect the wires together in a zip wire form and otherswrap the bundle with strands of plastic ribbons that can be easily removed to terminatethe cables in the bundle at the distribution panel or the room outlets. Figure 1-14 illus-trates some of the different cable bundle enclosures.

2+2 Bundled CablingA standard cable bundle is the 2+2 cable that includes two runs of UTP Cat 5e cable andtwo runs of RG-6 coaxial cable. Since these four cable runs typically satisfy the distrib-uted system needs of most homes, it is a very popular cable bundle for structured wiring.


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2+2+2 Bundled CablingAnother popular cable bundle adds two runs of fiber optic cable to 2+2 bundle to providefor even more current capability and future proofing to a home. The two fiber opticcables are multimode strands that can be used for a wide range of current and certainlyfuture applications.

Control Wire BundlesThere are several other types of structured wiring cable bundles, each with its own pur-pose. Some are variations of the 2+2 bundle with an additional run or UTP or coaxialcable included. However, one special purpose cable bundle is the control wire bundle.

Control wire bundles typically include a single run each of RG-59 or RG-6 coaxial cableand Cat 5e cable and two runs of 18-gauge stranded wire, which are used to cable keypads,room controls, intercoms with video, and for supplying power.

Common Home Automation Wire TypesFor reference purposes, I’ve included Table 1-8, which lists some industry designationsfor common audio and video cable and wire types. Although there are no industry stan-dards for the colors of the individual wires or the outer sheathing of structured wiring


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Figure 1-14Examples ofstructured wiringcable bundleenclosers

Photo courtesy ofSmarthome, Inc.



cables. For the most part, category UTP wiring has the same eight wire colors in fourmatched pairs, but the outer covering of other types of wire is available in a rainbow ofcolors. For best results, use the same color wire or cable for the same purpose through-out a home. This will make installation and troubleshooting a lot easier.

Table 1-8 provides includes some guidelines on which wiring type is recommendedfor particular subsystems, including a suggestion outer jacket color for the cables.

Test the WiringAfter what typically seems like miles of cable, speaker, coaxial, composite, and Cat 5 havebeen pulled into the walls, under the floor, or above the ceiling, and all of the connec-tors are attached and the wall plates are mounted, a second round of testing should beperformed. Yes, a second round. The first round of continuity and attenuation testingshould have been done immediately after each cable segment was pulled into place. Atthis point the wiring should be subjected to a full range of tests.

Even if you are absolutely sure of your work in soldering on the connectors and the con-nections made at the punch down block, always test the cable at this point in the process.


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Subsystem Usage AWG Conductors ConductorType

Shielded? CableColor

Audio LV audio 22 4 Stranded Shielded Yellow

Speakers,security siren

14 2 Stranded None Green

Speakers 16 4 Stranded None Blue

Basebandvideo

Compositevideo (cameras)

RG6/RG59 1 Solid Shielded Black/White

Communi-cations

Telephoneand data

25 (Cat 5e) 8 Solid None Blue

Firedetection

Smoke and heatdetectors

18 4 Solid None Red

IR control IR, LV wiring 22 4 Stranded None Pink

Security Door & windowcontacts

22 2 Stranded None Gray

Motion sensor,glass break

22 4 Stranded None Gray

Keypads 22 4 Stranded None Gray

Advancedkeypad withvoice pickupand playback

18 2 Stranded Shielded Pink

Driveway probe 18 3 Stranded Direct burial Black

Video Video signal RG6 1 Shielded Solid Shielded Black/White

Table 1-8 Recommended structured wiring cable application



Especially in new construction, a cable can be “nailed” or “screwed” when the drywallwas attached to the wall.

The testing process includes two steps: a visual inspection and a “buzz out” of the wire.Of course, a visual inspection must be done before new walls are completed or fromdown in the basement or crawl space or up in the attic. You are looking for the obvious,nails or screws piercing the cable, or cuts, gashes, kinks, and breaks in the cable.

A buzz out test of the cabling involves the use of a cable tester, which is also referredto as a “fox and hound.” What a cable tester does is send an electrical signal through thecable. Some testers require connectors to work; others use a vibrating electrical noise thatis placed on the wire by one device (the fox) and, hopefully, detected by the other device(the hound). This is a two-person job, period. Of course, all of the cables are labeled anddocumented on a wire chart. Completely test all wiring before beginning the fix-it process,if necessary.

For RG6 coaxial cabling, the testing should include a test for shorts, cable length, con-tinuity, and cable termination. For Cat-5 or Cat-6 cables, testers are available that willverify compliance of your wiring runs and terminations to these standards.

CROSS-REFERENCE Chapter 3 covers cable installation and testing in moredetail.

Chapter ReviewWhen installing wire and cable in a home, you must be aware of the voltage specifica-tion of the cable in use. There are certain cable types that are specified as low voltageand those specified as high voltage. Low voltage cable is designed to carry lower levels ofalternating current (AC) and direct current (DC) voltages.

Low voltage wiring is defined as being one of five types of circuits: communication cir-cuits, signal circuits, remote control circuits, motor control circuits, and power-limitedcircuits. Low voltage circuits are divided into three circuit classes: power-limited, remotecontrol and signaling, and direct current.

The most common types of electrical wiring used for home construction today are:modern non-metallic (NM), underground feeder (UF), and zip wire. Some older wiretypes you may encounter in a home are: flexible armored cable, metal conduit, early NM,and knob and tube.

The wire gauge used in a home depends on the number of amperes on a particularcircuit. Remember that a smaller gauge means a bigger and less flexible wire. Heaviergauge wire should be used to avoid voltage drops and to overcome heat problems.

Twisted-pair (TP) wiring is by far the most popularly installed media for networkingin just about any type of network for many reasons, including that it is inexpensive, easyto handle, and readily available. TP wire, Cat5, is the de facto standard for both Ethernetand Token Ring networks.


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UTP cable carries a variety of rating codes, which are assigned by the product perfor-mance and safety authorities and testing laboratories. The primary rating codes for UTPcable are defined by the NEC (National Electric Code), published by the National FireProtection Association, as CM, CMP, CMR. Twisted pair cable is available as shieldedtwisted pair (STP) and unshielded twisted pair (UTP).

Coaxial cable is constructed of a single inner core wire conductor that is encased in alayer of dielectric insulation, which is then wrapped by a wire mesh outer conductor andshield. A plastic sheathing covers the cable. Coaxial cable is single-ended cable with asingle signal path and a single return path. RG6 is the most common coaxial cable in-stalled in homes.

When an audio signal is transmitted, A/V cable stores (voltage) and releases (current) anelectrical wave at certain frequencies and amplitudes and is generally combined underthe term frequency. An audio/video signal consists of a collection of high and low fre-quency waves. An audio/video releases or passes an audio signal to the next componentwithout slowing down the signal. A cable with the ability to release the signal at the righttime is called in-phase.

A balanced audio cable uses both positive and negative carriers with a groundingcarrier added. In an unbalanced cable, the grounding signals are combined onto the nega-tive carrier.

Parallel or speaker wire is available in a variety of wire gauges, ranging from 8-gaugeon the high end to 24-gauge on the low end.

There are a variety of cables that can be used with video systems. The primary types ofvideo cable are: coaxial, component, and composite. Typically, 16-gauge stranded twisted-pair wire or 14- to 18-gauge audio cable is used for an average length speaker run.

The primary performance properties of metallic wire are: attenuation, cancellation,crosstalk, interference, and inductance.

Structured wiring involves the installation of wire homeruns to each room, zone,or area of a home. Structured wiring can be installed in two ways: pulling each individ-ual cable separately or pulling a cable bundle. A 2+2 cable includes two runs of UTPCat 5e cable and two runs of RG-6 coaxial cable. The 2+2+2 cable adds two runs of fiberoptic cable to 2+2 bundle.

Control wire bundles typically include a single run each of RG-59 coaxial cable andCat 5e cable and two runs of 18-gauge stranded wire, which are used to cable keypads,room controls, intercoms with video, and for supplying power.

Questions

1. Which of the following is not a home circuit type?

A. Communication circuits

B. Signal circuits

C. Wireless communication circuits

D. Power-limited circuits


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2. What is the term that describes the metallic core of a wire?

A. Armor

B. Conductor

C. Insulator

D. Jacket

3. What is the general name used for common household electric cable?

A. Modern NM/Romex

B. NMC

C. UF

D. Zip wire

4. According to Table 1-2, what wire gauge should be used for a circuit with 30amperes?

A. 20 AWG

B. 18 AWG

C. 14 AWG

D. 10 AWG

5. When an audio cable is able to release all audio frequencies without addingdelay, the cable is said to be

A. Out-of-phase

B. In-sync

C. In-phase

D. Synchronous

6. Which cable type has a single inner core wire conductor and a wire mesh outerconductor?

A. UTP

B. STP

C. Coaxial

D. 16g-4

7. Which type of audio/video cable includes carriers for both positive and negativesignals, but also includes a grounding carrier as well?

A. Coaxial

B. Balanced


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C. UTP

D. Parallel pair

8. Which cable type resembles a lamp cord?

A. Coaxial

B. Balanced

C. UTP

D. Parallel pair

9. What is the cable property that states the distance at which the signal travelingon a cable begins to weaken?

A. Attenuation

B. Cancellation

C. Crosstalk

D. Interference

10. What is the common used term that describes a bundled cable with two runsof UTP and two runs of coaxial cable?

A. UC cable

B. Structured bundle

C. 2+2

D. 2+2+2

Answers

1. C. Wireless communication circuits. By being wireless, these systems are notpart of a house’s wiring structure.

2. B. Conductor. A conductor has the ability to store and release an electrical current.

3. A. Modern NM/Romex. Non-metallic cable is the currently accepted standardfor general household electrical wiring.

4. D. 10 AWG. This wire is rated for a 30-amp, 240-volt system.

5. C. In-phase. The opposite is true when a cable releases lower frequencies laterthan its higher frequencies.

6. C. Coaxial. Both the inner core (positive) and the outer conductor (negative)carry signals.

7. B. Balanced. The balance comes from having conductors for both positive andnegative signals and a separate conductor for grounding but on other cables maybe combined onto the negative carrier.


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8. D. Parallel pair. This cable looks very much like a lamp cord and is also referredto as rip cable for the ease with which the two conductors can be separated.

9. A. Attenuation. Attenuation can be overcome with shorter cable runs or a signalextender, such as a repeater.

10. C. 2+2. This type of cable combines two runs of UTP and two runs of coaxialcable into a single cable bundle that is easier to install and provides for futureexpansion of the home system.


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