The instructional design of Modern Residential Wiring includes student-focused learning tools to help you succeed. In the textbook you will find the following features that will guide you through your learning experience. Chapter Opening Materials Each chapter opening contains an outline and a list of learning objectives and technical terms. The Chapter Outline previews the topics that will be covered. Objectives clearly identify the knowledge and skills to guide your learning as you progress through the chapter. Technical Terms list key vocabulary you will encounter as you read the content. Special Features Special features are used throughout the body of each chapter to extend learning and knowledge. Code Alerts highlight specifi c items from the National Electrical Code and from typical building codes. Pro Tips provide advice and guidance that is especially applicable for on-the-job situations. Safety Notes alert you to potentially dangerous materials and practices. Thinking Green features highlight key items related to sustainability, energy effi ciency, and environmental issues. x Features of the Textbook 177 Chapter Outline 12.1 Wiring Methods and Materials 12.1.1 Mechanical Considerations 12.1.2 Electrical Connections 12.1.3 Working Clearances 12.1.4 Identifi cation for Safety 12.2 Preparation of Conductors 12.2.1 Stripping Wire 12.2.2 Splicing Conductors 12.3 Wiring Switches and Receptacles 12.3.1 Switch Wiring 12.3.2 Receptacle Wiring 12.4 Wiring Circuits CHAPTER 12 Device Wiring Objectives Information in this chapter will enable you to: • Discuss the significance of listing or labeling electrical devices and materials. • Properly prepare conductors for connection to devices and equipment. • Make safe, secure conductor splices. • Demonstrate the proper method for attaching conductors to switches and receptacles. • Ground a receptacle. • Split-wire a receptacle. I n the fi nishing stages of a wiring project, the electrician makes the fi nal connection between conductors and switches and recep- tacles as well as fi xtures, motors, and other devices. NEC Article 110 specifi es requirements for the installation of such materials and equip- ment. This chapter focuses on wiring switches and receptacles. Lighting is covered in Chapter 13, Lighting Systems, and motors are covered in Chapter 22, Motors. 12.1 Wiring Methods and Materials Details on various wiring methods and materi- als are presented in the articles of Chapter 3 of the NEC. These articles describe, defi ne, limit, and specify the methods and materials of wir- ing used in the electrical industry today. Technical Terms break-off fin duplex receptacle grounding-type receptacle pigtail receptacle splicing split-wired receptacle wire connector Copyright Goodheart-Willcox Co., Inc. CODE ALERT Avoiding Violations Common code violations can be avoided with a thorough knowledge of Articles 110 and 300, which specify requirements for electrical intalla- tions and wiring methods and materials. If you become knowledgeable in these areas of the NEC, your installations will be less likely to suffer the time-consuming, embarrassing, and costly “red-flagging” during an inspection. 200 Section 3 Installation Copyright Goodheart-Willcox Co., Inc. bayonet, and prong-style. Every light fixture is labeled with the code of the lamp base it accepts. Halogen lighting is a form of incandescent lighting that includes a metal filament inside a bulb that is filled with pressurized halogen gas. The gas increases the brightness of the light and the life of the filament. Halogen lamps operate very hot and must be handled carefully. Never change a halogen lamp with bare hands. The oil from your skin can cause the lamp to heat up too quickly, shortening the life of the lamp and possibly causing it to explode. Because halogen lighting can pro- duce a lot of light in a small lamp size, it is often used in small accent fixtures and in low- voltage systems. PRO TIP Different Base Types Always check the label of a lamp base to ensure the proper one is selected. Not only are there several different sizes of Edison bases, there are also over 75 varieties of pin-style bases. 13.4.2 Light Sources Electric lamps use a variety of technologies to produce visible light. The three primary types of lamps are: • Incandescent • Fluorescent • LED. Incandescent lighting has been the predomi- nant type used in household lamps since the late 1800s, but it is steadily being replaced by more energy-efficient light sources, primarily fluores- cent and LED. In addition to energy use, different light sources offer different lighting characteris- tics, including the quality, or “temperature,” and the brightness of the light produced. Incandescent Lamps Incandescent lamps are still the standard for many household lighting applications. They produce light by running electricity through a thin metal fi lament, causing it to heat and emit light-producing photons. This phenomenon creates a warm, soft light that most people fi nd appealing.. Incandescent lamps typically are the least expensive of the main lamp types, but they also have the shortest life, ranging from 700 to 1,000 hours. However, the most significant drawback of incandescent lighting is its energy consumption. Up to 90% of the energy used by an incandescent lamp is wasted as heat, released in the form of infrared light photons that are outside of the vis-- ible spectrum. That means only about 10% of the energy used actually produces visible light. The excessive waste heat also means that incandes-- cent lamps get very hot, making them unsuitable and possibly in some applications. Fluorescent Lamps Fluorescent lamps produce light by conduct- ing an electric current through an inert gas. This process results in an ultraviolet light that works with the phosphor coating of the lamp to convert invisible light into bright, white light. Fluorescent lamps are widely available as fl uo- rescent tube lamps and compact fl uorescent lamps (CFLs).. Fluorescent tubes come in the standard straight tubes used in utility fixtures as well as round and U-shaped tubes used in more com- pact fixtures. Most fluorescent tubes do not include ballasts so they must be used in fixtures that contain a ballast.bal The diameter of a fluorescent tube is mea- sured in eighths of an inch and is referenced in the lamp’s name. A T12 lamp is a tube that mea- sures 12 eighths of an inch (1 1/2″) in diameter. SAFETY NOTE Maximum Wattage Ratings Most people ignore the little labels on light fix- tures that specify a maximum lamp wattage rating, but the labels are there for a very good reason. Wattage relates to how hot the lamp gets when it is illuminated. A fixture rated for 60 watts is designed to withstand the heat gen- erated by a 60-watt incandescent lamp. Using a higher-wattage lamp with this fixture can melt the insulation on the fixture wiring, possibly leading to fixture failure, a dangerous short cir- cuit, or a house fire. light-producing ns. s pheno e a ling ty y ran ing m significant f lig g gy p inf f sp ly t gy y li ht. h al t at des g y g a d bly ddangerous ang appl pr res w ph ble p r la l Fl tu ght us r d d U-sha p M i s co e eter eig eig 224 Section 3 Installation Copyright Goodheart-Willcox Co., Inc. Other Units Although only a few specifi c types of heater units are discussed here, there are many other types available. The choice depends on many factors: • Size of area to be heated • Heat loss factors • Amount of insulation present • Climatic conditions • Desired temperature of area to be heated • Style preference. Baseboard Units the and small commercial-type are baseboard or 240 volts, a 35 to 4.5 (4.5 on a Cadet Figure 14-10. Electric heating units are available in a variety of sizes, shapes, styles, and power ratings. Units typically include a mounting box that is installed in the wall, a heating unit, and a cover plate. THINKING GREEN Energy-Efficient Heating and Cooling Water heating and space heating and cooling together use about two-thirds of the energy in the average home. Energy-efficient heating and cooling appliances can lower a home’s energy use and reduce energy costs signifi- cantly. In most cases, efficient appliances cost more to purchase than conventional models, but due to lower operating costs, efficient appliances can save money over their life- times. Consider the purchase price and lifetime operating cost of an electric appliance to determine its cost efficiency in addition to energy savings. Sometimes, more efficient technologies are less expensive to use and to purchase and install. For example, evapora- tive coolers (suitable in dry climates only) cost about half as much as conventional central air conditioners to purchase and install and use about one-quarter as much electricity to operate. Exploded View Wall-Mount Baseboard