Audel house wiring

Audel house wiring

P1: FCH/FFX P2: FCH/FFX QC: FCH/FFX T1: FCH GB080-FM GB080-Rosenberg-v1 August 4, 2004 15:22 Audel TM House Wiring All New 8 th Edition Paul Rosenberg Roland Palmquist P1: FCH/FFX P2: FCH/FFX QC: FCH/FFX T1: FCH GB080-FM GB080-Rosenberg-v1 August 4, 2004 15:22 Vice President and Executive Group Publisher: Richard Swadley Vice President and Executive Publisher: Bob Ipsen Vice President and Publisher: Joseph B. Wikert Executive Editorial Director: Mary Bednarek Editorial Manager: Kathryn A. Malm Executive Editor: Carol A. Long Production Manager: Gerry T. Fahey Development Editor: Eileen Bien Calabro Production Editor: Ava Wilder Text Design & Composition: TechBooks Copyright C  2004 by Wiley Publishing, Inc. All rights reserved. Copyright C  1999 by Macmillan USA. 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Limit of Liability/Disclaimer of Warranty: While the publisher and author have used their best efforts in preparing this book, they make no representations or warranties with respect to the accuracy or completeness of the contents of this book and specifically disclaim any implied warranties of merchantability or fitness for a particular purpose. No warranty may be created or extended by sales representatives or written sales materials. The advice and strategies contained herein may not be suitable for your situation. You should consult with a professional where appropriate. Neither the publisher nor author shall be liable for any loss of profit or any other commercial damages, including but not limited to special, incidental, consequential, or other damages. For general information on our other products and services please contact our Customer Care Department within the United States at (800) 762-2974, outside the United States at (317) 572- 3993 or fax (317) 572-4002. Trademarks: Wiley, the Wiley Publishing logo, and Audel are trademarks or registered trademarks of John Wiley & Sons, Inc., and/or its affiliates. National Electrical Code is a registered trademark of the National Fire Protection Association, Inc., Quincy, MA. All other trademarks are the property of their respective owners. Wiley Publishing, Inc., is not associated with any product or vendor mentioned in this book. Wiley also publishes its books in a variety of electronic formats. Some content that appears in print may not be available in electronic books. Library of Congress Cataloging-in-Publication Data: Printed in the United States of America 10987654321 eISBN: 0-764-57692-5 P1: FCH/FFX P2: FCH/FFX QC: FCH/FFX T1: FCH GB080-FM GB080-Rosenberg-v1 August 4, 2004 15:22 Contents Foreword vii Chapter 1 Wiring Basics 1 Safety 1 The National Electrical Code 3 Enforcement 9 Chapter 2 Electrical Services 11 Service Basics 11 Overhead Service Components 15 Residential Underground Service 15 NEC Requirements for Services 20 Service-Entrance Location 21 Installation of Service Drops 22 Installation of Service Laterals 25 Service Entrances and Equipment 28 Grounding of Services 31 Chapter 3 Branch Circuits and Loads 47 Definitions 48 Calculations 50 Placing Outlets 58 Placing Switches 60 Chapter 4 Materials and Methods 61 Nonmetallic-Sheathed Cable (Types NM and NMC) 61 Underground Feeder and Branch-Circuit Cable (Type UF) 72 Metal-Clad Cable (Type AC) 75 Service-Entrance Cable (Types SE and USE) 77 Electrical Metallic Tubing 83 Rigid Metal Conduit 91 Boxes and Fittings 96 iii P1: FCH/FFX P2: FCH/FFX QC: FCH/FFX T1: FCH GB080-FM GB080-Rosenberg-v1 August 4, 2004 15:22 iv Contents Chapter 5 Wiring for Electric House Heating 117 Environmental Issues 117 Electrical Protection Issues 118 Installation of Electric Heating 119 Chapter 6 Mobile Homes 127 Requirements Differences 127 Chapter 7 Cable TV, Broadband, Telephone, and Security 135 Cable TV Wiring 135 Telephone Wiring 136 Broadband and Home Networks 140 Security Systems 145 Chapter 8 How to Wire a House 147 The Process 147 Service-Entrance Location 151 Service Size 154 Feeder Panels and Branch-Circuit Overcurrent Devices 156 Number of Outlets Per Circuit 159 Circuits 162 Conduit 163 Circuit Layout 167 Color-Coding 170 Box Fill 173 Installation of Cables 176 Box and Device Grounding 178 Wiring Basements 180 Adding Wire to Old Homes 181 Appendix A Calculations for Dwellings 183 Calculation No. 1 183 Optional Calculations 186 Calculation No. 2 188 Calculation No. 3 188 P1: FCH/FFX P2: FCH/FFX QC: FCH/FFX T1: FCH GB080-FM GB080-Rosenberg-v1 August 4, 2004 15:22 Contents v Calculation No. 4 189 Calculation No. 5 191 Motor Loads 192 Appendix B Farm Buildings 193 Example of a Farm Calculation 194 Appendix C Audio and Home Theater Installations 199 Sound Systems 199 Integrated Entertainment Systems 204 Home Theater 205 Video Distribution 210 Appendix D The Internet as Entertainment 213 Why Use a Computer for Entertainment? 213 Computers Outfitted for Entertainment 215 Index 221 P1: FCH/FFX P2: FCH/FFX QC: FCH/FFX T1: FCH GB080-FM GB080-Rosenberg-v1 August 4, 2004 15:22 P1: FCH/FFX P2: FCH/FFX QC: FCH/FFX T1: FCH GB080-FM GB080-Rosenberg-v1 August 4, 2004 15:22 Foreword It has been a pleasure for me to put together a house wiring text that would provide serious trade knowledge to a general audience. It has been my experience that virtually all do-it-yourself books are short on seriousness and long on “five easy steps.” Installing electrical wiring is not supposed to be simple or easy. Electrical wiring is a serious undertaking. Basic wiring projects are not beyond the skill of a homeowner, but neither are they something that can be taken lightly. I do not like treating wiring as if it were as simple as applying paint to a wall; it is not. Doable? Yes, definitely. But never “quick and easy.” In this book, I have taken the information that is really necessary to wire a house properly, and have put it into an order and form that can be understood by a nonprofessional. This is not a dumbed-down book. It is a professional level text, with a bit of extra explanation added. Furthermore, this book covers only house wiring. Narrowing the subject allows for a book that covers the material fully without being overwhelmingly long or complex. r Chapter 1 covers the basics of the National Electrical Code (NEC) and general safety. The NEC contains all of the rules that are necessary to perform safe electrical installations. They are also the rules that all electrical installations are required to meet. Electrical wiring that does not meet NEC requirements will not be approved and is probably unsafe. So, understanding the NEC is absolutely critical for any installer of electrical wiring. This chapter explains what the NEC is all about, the particular wording it uses, and how to use it with a minimum of difficulty. r Chapter 2 details the requirements and methods for installing an electrical service entrance. This is the part of an electrical system that is exposed to the most hazards, and it needs its own careful explanation. r Chapter 3 deals with the branch circuits that power all of the receptacles, lights, and appliances we use in our homes. r Chapter 4 covers the materials and methods for house wiring— the various cables, wires, conduits, and boxes that make up a complete electrical installation. All of these are items that must be applied properly. Again, the rules and methods are not especially difficult, but they do need to be addressed directly. vii P1: FCH/FFX P2: FCH/FFX QC: FCH/FFX T1: FCH GB080-FM GB080-Rosenberg-v1 August 4, 2004 15:22 viii Foreword r Chapter 5 covers electric heating systems, which are very im- portant in some areas and seldom used in others. r Chapter 6 covers mobile homes, which have a few special re- quirements and must be wired correctly to avoid hazards. r Chapter 7 covers several types of communication wiring (tele- phone, cable TV, broadband Internet, and home networks) as well as security systems. These systems are not generally as hazardous as wiring for light and power, but they must be in- stalled correctly if they are to do their jobs. Installing them is in many ways easier than installing power wiring. r Chapter 8 is unique in that it is especially focused on the pro- cess of actually wiring a house. All of the text in this chapter follows the process of wiring a house, roughly from beginning to end. r Appendix A explains and gives examples of load calculations. These calculations are frequently required to obtain an electri- cal permit. This Appendix outlines the process step-by-step. r Appendix B covers the requirements and calculations for farm buildings. r Appendix C covers the requirements for installation of audio and home theater systems. r Appendix D discusses the components and connections needed for various methods of delivering electronic entertainment ob- tained from the Internet. Whether professional electrician or homeowner, I think that you’ll find that this book contains all of the essential information you need to wire a home properly. Read it carefully, and have it nearby as you undertake your house-wiring project. Paul Rosenberg P1: FCH/FFX P2: FCH/FFX QC: FCH/FFX T1: FCH GB080-01 GB080-Rosenberg-v1 July 30, 2004 15:39 Chapter 1 Wiring Basics In any complex undertaking there are fundamental issues that must be mastered if the project is to be successful. For the wiring of a house, those fundamentals are the safety of the installation and the safety of the installer. Everything else follows from there. The wiring you install must not hurt people or damage property. This wiring may remain in place and function for many decades, and it may be used by dozens if not hundreds of people. Your first concern is that it operate safely. Through much of this book, we will explain how to build a house wiring system that will provide the services and capacities you need. Those requirements are cer- tainly very important, but they are a far second in importance to safety. Wiring systems can always be expanded and improved, but an unsafe system cannot be tolerated. As we proceed through this text, and as you proceed through your wiring project, you can never entirely let this thought out of your mind: Electric power is one of the most useful things humans have ever discovered and is a great blessing upon humanity, but it is an impersonal and amoral force. If wiring is not installed properly, it will cause harm just as readily as it will cause benefit. Safety As just mentioned, there are two primary safety concerns in house wiring: the safety of the installation and the safety of the installer. We will begin our discussion with the safety of the installer. Construction Site Safety Your first concern is job-site safety. We are discussing construction projects here, and construction sites are inherently hazardous. In fact, most accidents suffered by electricians are related to general construction hazards rather than electrical shock. Such hazards as stepping on nails or screws, air hammer accidents, loose flooring, falls, and falling construction materials are the most common causes of injuries. When working on any construction site, awareness is your first priority. What are the carpenters doing? Who else has been to the job? What did they install? Did they complete it? Is it safe yet? You cannot assume anything on a construction site. Any long-time construction worker can tell you stories about people they knew who were hurt (or worse) simply because they assumed something. 1 P1: FCH/FFX P2: FCH/FFX QC: FCH/FFX T1: FCH GB080-01 GB080-Rosenberg-v1 July 30, 2004 15:39 2 Chapter 1 Your eyes must be open at all times on any construction site. This is your job, and you cannot delegate it to anyone else—ever. It is difficult to get this message across strongly enough. House wiring is simpler than industrial wiring, to be sure, but it still re- quires that the installer be informed, cautious, and sensible. Gen- erally, young construction workers never understand this necessity completely until they have a near miss (or worse). Then they begin to understand. Please try to avoid that pattern. As for avoiding electrical shock or burn, additional care must be taken to know which wire is connected to what, and to maintain color codes strictly. Hot wires in a house should always be black or red. Neutrals should always be white, grounds always green, and only switch leg conductors should be other colors. This discipline cannot be deviated from, or you will be in jeopardy. The risks from wiring are shock and burn. Shocking generally occurs when your body (or part of it) gets into some position where it completes a circuit. That is, your body becomes a conductor— flesh substituting for a wire. Usually this happens when you touch a hot wire with one part of your body while another part of your body is touching ground. For house wiring at 120 volts to ground, this is painful but seldom leads to real damage. However, if you are very well grounded (standing in a puddle of water, for example), death is certainly possible. Be careful. Burning generally occurs when you accidentally put a tool in between two live conductors, thus creating a short circuit. In these cases, a very high level of current will immediately begin to flow through your screwdriver, pliers, or whatever piece of metal you have put where it doesn’t belong. Such high currents cause so much heating that they will, within milliseconds, melt and/or vaporize the copper of the conductors, the steel of the tool, or both. Because gas takes many, many times more volume than the same mass of a solid, an explosion results. The solid copper that occupied only one-tenth of a cubic centimeter now requires several cubic centimeters as a gas. And since this transition takes only a fraction of a second, it blows molten copper away from the location of the conductors and toward you (among other things). In most cases, at residential levels of current and voltage, such accidents result in burns that heal in a week or two. But worse can happen, and occasionally does. Again, be careful. Remember that electricity can injure and kill people and ignite fires. Higher voltages are obviously more dangerous than lower volt- ages, but even normal household voltages can hurt you. If you are not experienced with electrical work, do not work on live circuits!