Ultimate Guide Wiring, Updated 9th Edition E-Book

• Herausgeber: Creative Homeowner
• Kategorie: Lebensstil
• Serie: Ultimate Guides
• Sprache: Englisch
• Veröffentlichungsjahr: 2022

Seitenzahl: 478

Beschreibung

The most recent edition to the best-selling wiring manual, Ultimate Guide: Wiring, 9th Edition demystifies home wiring and residential electrical systems with easy-to-understand language, step-by-step photography, and detailed illustrations. Homeowners and DIYers will learn how their home's electrical system works from the inside out and how to complete installations and repairs. This project-based book shows how to select the right cable, wires, and other equipment, and how to run wiring through walls and between floors. Projects guide the reader through installing switches, outlet receptacles, electrical appliances, and lighting systems. The book also shows how outdoor lighting, including security and low-voltage systems, can help homeowners improve and illuminate the exterior areas around their homes. This most recent edition has been updated with the latest information on everything from recent code standards and smart home automation to renewable energy, LED wafer lighting, dimmer switches, new indoor and outdoor emergency systems, and more.

Leseprobe

ULTIMATE GUIDE

WIRING

9TH UPDATED EDITION

Technical Editor for Updated Edition: Charles T. Byers

Assistant Professor, Residential Remodeling Technology, AAS, AST,Thaddeus Stevens College of Technology

CREATIVE HOMEOWNER®

COPYRIGHT © 2001, 2004, 2007, 2010, 2017, 2022

This book may not be reproduced, either in part or in its entirety, in any form, by any means, without written permission from the publisher, with the exception of brief excerpts for purposes of radio, television, or published review. All rights, including the right of translation, are reserved. Note: Be sure to familiarize yourself with manufacturer’s instructions for tools, equipment, and materials before beginning a project. Although all possible measures have been taken to ensure the accuracy of the material presented, neither the author nor the publisher is liable in case of misinterpretation of directions, misapplication, or typographical error.

Creative Homeowner® is a registered trademark of New Design Originals Corporation.

The designations National Electrical Code® and NEC® are registered trademarks of the National Fire Protection Agency.

ULTIMATE GUIDE: WIRING

MANAGING EDITOR

Fran J. Donegan

CONTRIBUTING WRITERS

John Caloggero, Rex Cauldwell,Steve Willson

PHOTO COORDINATOR

Mary Dolan

PROOFREADER

Sara M. Markowitz

DIGITAL IMAGING SPECIALIST

Frank Dyer

INDEXER

Schroeder Indexing Services

TECHNICAL ADVISORS

John Caloggero; Perter Eng;Charles L. Rogers, CertifiedInstructor, National Centerfor Construction and Research;Joseph A. Ross, Ross ElectricalAssessments; David Shapiro

COVER DESIGN

David Geer

ILLUSTRATIONS

Clarke Barre, Robert Strauch, Charles Van Vooren, Ian Warpole

FRONT COVER PHOTOGRAPHY

Freeze Frame Studio

BACK COVER PHOTOGRAPHY

John Parsekian/CH

UPDATED EDITION

MANAGING EDITOR:

Gretchen Bacon

EDITOR:

Jeremy Hauck

TECHNICAL EDITOR:

Charles T. Byers, Assistant Professor,Residential Remodeling Technology, AAS, AST,Thaddeus Stevens College of Technology

DESIGNER:

Wendy Reynolds

Ultimate Guide: Wiring, 9th Updated EditionPrint ISBN 978-1-58011-575-9eISBN: 978-1-63741-156-8

Library of Congress Control Number: 2022938737

We are always looking for talented authors. To submit an idea,please send a brief inquiry to [email protected].

Creative Homeowner®, www.creativehomeowner.com, is distributedexclusively in North America by Fox Chapel Publishing Company, Inc.,800-457-9112, 903 Square Street, Mount Joy, PA 17552,and in the United Kingdom by Grantham Book Service,Trent Road, Grantham, Lincolnshire, NG31 7XQ.

Safety

Although the methods in this book have been reviewed for safety, it is not possible to overstate the importance of using the safest methods you can. What follows are reminders—some do’s and don’ts of work safety—to use along with your common sense.

  Always use caution, care, and good judgment when following the procedures described in this book.

  Always be sure that the electrical setup is safe; be sure that no circuit is overloaded, and that all power tools and electrical outlets are properly grounded. Do not use power tools in wet locations.

  Never modify a plug by bending or removing prongs. When prongs are bent, loose or missing, replace the entire device.

  Don’t use 3-prong-to-2-prong cord adapters to overcome ground connections.

  Be sure all receptacles and electrical conductors are properly grounded.

  If a plug prong breaks off in a receptacle, do not attempt to remove it. Turn off the circuit, and call a licensed electrician.

  Be sure receptacles are mounted securely in their boxes and do not move when the plug is inserted. A loose receptacle can cause a short circuit.

  Do not use loose receptacles or other faulty electrical equipment until it is repaired or replaced and inspected by a licensed electrician.

  Replace all damaged electrical enclosures such as receptacle, switch, and junction boxes.

  Use extension cords only when necessary, on a short-term basis; never use extension cords in place of permanent wiring.

  Be sure all extension cords are properly sized and rated for the use intended.

  Keep electrical cords away from areas where they may be stepped on, pinched between door jambs, or otherwise damaged.

  Don’t use appliance or extension cords that show signs of wear, such as frayed or dried sheathing or exposed wires.

  Visually inspect all electrical equipment and appliances before use.

  Never staple, nail, or otherwise attach an extension cord to any surface.

  Always turn off tools and appliances before unplugging them.

  Never unplug a tool or appliance by yanking on the cord; always remove the cord by the plug.

  Always keep the area in front of your main panel clear and dry. Work on a rubber mat or dry board and maintain an unobstructed area of at least 3 feet in front of the panel. The panel must be easily accessed.

  Keep dust, lint, and other combustible materials away from electrical panels, receptacles, and appliances.

  Keep electrical panel doors closed and latched when not in use.

  Keep all electrical equipment away from any source of water unless it is rated for use in wet areas, such as a wet-dry shop vacuum.

  Use ground-fault circuit interrupters (GFCIs) wherever possible. GFCIs are required in all wet, damp, or moist areas.

  Limit use of receptacles to one appliance. If more than one appliance will be on a circuit, use an approved plug strip with a built-in circuit breaker.

  Use proper lighting in areas where the risk of an electrical hazard is present and keep emergency backup lighting readily available.

  Keep all energized parts of electrical circuits and equipment enclosed in approved cabinets and enclosures.

  Use only tools that have double insulated casings.

  Always be aware of the potential hazards when doing electrical work of any kind.

  Be sure to use appropriate protective equipment when doing electrical work (safety glasses, insulated gloves, rubber mats, etc.).

Contents

Introduction

PART I: PROJECTS, IMPROVEMENTS, REPAIRS

CHAPTER ONE

WIRING METHODS

Basic Circuitry

• Charting Circuits • Designing a Kitchen Wiring Plan • Calculating Ampacity

Basic Wiring

• Height and Clearance Requirements • Installing Electrical Boxes • Preparing for Inspection • Surface Wiring • Running Cable through Framing • Opening and Closing Walls

Receptacles

• Duplex Receptacles • High-Voltage Receptacles • GFCI Receptacles

Switches

• Single-Pole Switches • Three-Way Switches • Four-Way Switches • Dimmer Switches

Plugs, Cords, and Sockets

• Standard Plugs • Light Sockets and Switches • Multi-Socket Switches

New Circuits and Service Panels

• AFCI Breakers • Dual-Function AFCI/GFCI Breakers

CHAPTER TWO

LIGHTING

Lighting Types

• Incandescent LED • Lightbulb Burnout • Fluorescent • Energy-Saving Compact Fluorescent Lamps • Quartz Halogen

Lighting Fixtures

• Recessed • Surface-Mounted • Track Lighting • Chandeliers • Vanity Lighting • Under-Cabinet Lighting • Cable Lights

Indoor Lighting Design

• Basic Fixture Types • How Much Light Do You Need?

CHAPTER THREE

APPLIANCES AND EQUIPMENT

Selection

• Shopping Tips

Appliances

• Dishwasher • Range Receptacle • Dryer Receptacle • Waste-Disposal Unit • Hot-Water Dispenser • Island Receptacle

Ventilating and Heating Equipment

• Ceiling Fans • Whole-House Fans • Calculating Fan/Vent Sizes • Range Hood • Ventilating Fans • Electric Water Heater • Radiant Floor Heating • Baseboard Heating • Recessed Wall Heater

Safety Equipment

• Hardwired Smoke Detectors

CHAPTER FOUR

SPECIALTY WIRING

Low-Voltage Power

• What It Is and How It Works • Low-Voltage Transformers • Low-Voltage Wire

Wiring Applications

• Bells and Chimes • Timers • Sensors and Alarms • Thermostats • Antennas • Telecommunications

CHAPTER FIVE

OUTDOOR WIRING AND LOW-VOLTAGE LIGHTING

What Makes It Different

• Circuiting • Outdoor Conduit and Cable Types

Materials and Equipment

• Outdoor Electrical Boxes • Receptacles and Switches • Conduit, Connectors, and Fittings • Lamps and Yard Lights

Outdoor Lighting Design

• Sensors and Timers

Wiring Preparation

• Planning • Trenching

Outdoor Wiring Methods

• Receptacles • Switches • Lights • Lampposts

Low-Voltage Lighting Basics

• Low-Voltage Lighting

Swimming Pools and Spas

• Code Requirements • Aboveground Swimming Pools • Spas • Underwater Pool Lighting • Underwater Lighting Circuits

CHAPTER SIX

EMERGENCY POWER EQUIPMENT

Lightning Protection

• Understanding Lightning • Lightning Rods • Lightning Protection Systems

Surge Protection

• Electrical Surges • Whole-House Protection • Point-of-Use Protection • Grounding

Optional Standby Generators

• What They Are and How They Work • Selection • Placement and Hookup • Transfer-Switch Panels

CHAPTER SEVEN

HOME AUTOMATION

Smart Home Basics

• Power Line Carrier Control • Timer Control • Computer Control • Wireless Remote Control • Home Networking • Surge Control

Data-Transmission Standards

• Design Protocols • X-10 • CEBus • LonWorks • Smart House

Uses for Home Automation

• Lighting Systems and Appliances • Plumbing • Heating, Ventilating, and Air Conditioning • Home Security • Outdoor Systems • Telecommunications and Networking • Entertainment Systems

X-10 Projects

• Sprinkler System • Voice-Dial Home Security System

Home Networking

• Structured Cabling • Making Connections • Structured Cabling Outlets • Structured Media Center • Computer Networks

Smart Home Technology and Apps

PART II: FUNDAMENTALS

CHAPTER EIGHT

UNDERSTANDING ELECTRICITY

Fundamentals of Electricity

• Electricity Defined • Terminology of Electricity • Calculating the Ampacity of an Electric Water Heater

How Electricity Is Provided

• Generation • Transmission • Point of Use • Service Entrance Panel

How Electricity Works

• Electric Current Flow • Flow Resistance

Working Safely with Electricity

• Basic Rules of Safety • Short Circuits

Grounding Systems

• Main Panel Ground • Overload Protection • Grounding Rods • Ground Faults on Appliances • Importance of Testing for Ground • Bonding Jumpers

CHAPTER NINE

TOOLS AND THEIR USES

Pulling Wires and Fuses

Cutting and Twisting Wires

Stripping and Crimping Wires

Connecting, Supporting, and Protecting Wires

Locating, Measuring, and Marking

Hole-Making, Cutting, and Striking

Working with Conduit

Safety

Testing Circuits

CHAPTER TEN

MATERIALS AND EQUIPMENT

Wires and Cables

• Types and Designations • Insulation Categories • Splicing Wires • Wire Ampacity • Underground Cable • Armored Cable • Nonmetallic Cable

Service Panels

• Types and How They Work • Hot Buses • Neutral/Grounding Buses

Circuit Breakers

Fuses

Electrical Boxes

• Types and Capacities • Plastic Boxes • Metal Boxes • Weatherproof Boxes • Special Boxes • Box Extensions and Mounting Brackets

Receptacles

• Duplex Receptacles • Nongrounded Receptacles • Appliance Receptacles • Isolated Ground and GFCI Receptacles

Switches

• Types and Designations • Toggle Switches • Dimmer Switches • Pilot-Light Switches • Timer Switches • Electronic Switches

Low-Voltage Transformers

• Types and Applications

Raceways

• Raceway Applications • Raceway Components

Conduit

• Conduit Components

Resource Guide

Glossary

Credits

Metric Equivalents

Introduction

ULTIMATE GUIDE: WIRING provides you with the information and confidence you need to make electrical repairs and improvements to your home safely and effectively. Written in easy-to-understand language that is accompanied by informative illustrations and photographs, Ultimate Guide: Wiring gives a clear understanding of how electricity works, how it is delivered to your house, how it is distributed throughout your home. Step-by-step sequences guide you through the most common electrical projects, including installing switches and outlets, repairing and adding lighting fixtures, and hooking up major appliances. You’ll also find information on low-voltage wiring systems, outdoor lighting and wiring, home networks, Wi-Fi applications, lightning protection, surge protection, and standby generators. The information that accompanies each project includes the tools and materials you will need to perform the work at hand. This latest edition includes changes to the most recent version of the National Electrical Code. But before beginning any electrical project, check with your local building department for requirements in your area.

GUIDE TO SKILL LEVEL

Easy. Made for beginners.

Challenging. Can be done by beginners who have the patience and willingness to learn.

Difficult. Can be handled by most experienced do-it-yourselfers who have mastered basic construction skills. Consider consulting a specialist.

Ultimate Guide: Wiring will teach you to approach your home wiring projects with the confidence that comes from knowledge. You will see that there is really nothing mystical about installing a dimmer switch or changing a receptacle. As with changing a lightbulb, the work can be simple once you know how to do it, and to do it safely.

As a teaching tool, Ultimate Guide: Wiring provides clear instruction, ease of use, and an entertaining presentation. Some of the book’s features include:

  Updated notes on material availability and pricing, because these considerations have become a major issue in the industry since the spring of 2020 and will continue for the foreseeable future, as demand for limited supplies has caused prices to elevate dramatically. For example, the stocked quantities of breakers that protect AFCI and GFCI are in the single digits at home centers, and the same applies for generic single and double pole breakers. Rising copper futures and a limited supply of the PVC conductor insulation and the cables’ outer sheathing has likewise led to a shortage of Romex wire. It pays huge dividends to check pricing and availability from several sources before beginning any electrical project. Careful planning and execution of every aspect of your work is essential in today’s market.

  Step-by-step photographs illustrate how to wire electrical boxes, switches, receptacles, and even specific appliances. Great effort has been made to include photos that will help you to understand how circuits work, show you real components and wiring, and take you step-bystep through projects. Projects include difficulty ratings (opposite), tools, and materials.

  Informative art, including cutaway drawings, clarify concepts not easily demonstrated in photographs.

  Charts and tables provide information such as the correct size and type of wire for a particular project.

  Detailed how-to wiring diagrams reinforce the step-by-step procedures and often add variations and alternative approaches.

  Smart Tips provide tidbits of interesting and insightful information about various subjects, often related to your project.

  Sidebars accompanying the how-to steps frequently discuss related topics that don’t require a tremendous amount of detail.

Of course, mastering this book will not qualify you to become a licensed electrician, but it will provide you with enough knowledge of electrical work to realize when someone else is doing it wrong. Inevitably, either for reasons of safety or simply because it is required by your local or state electrical code, you may need the services of a licensed electrician, especially for work on your service entrance or within your main electrical panel. In those cases, you should know not only what an electrician must do, but also how he or she must do it. Ultimate Guide: Wiring will help you to do just that.

Ultimate Guide: Wiring conforms to the current National Electrical Code® (NEC). However, electrical codes are not design manuals. Codes are written to establish minimal standards. It is always better to exceed code requirements. Also, be aware of local code restrictions that may be more stringent than the NEC. If you are ever uncertain about an electrical requirement, don’t take unnecessary risks! When in doubt, call a licensed electrician.

PART I: Projects,Improvements, Repairs

1wiringmethods

BASIC CIRCUITRY

BASIC WIRING

RECEPTACLES

SWITCHES

PLUGS, CORDS, AND SOCKETS

NEW CIRCUITS AND SERVICE PANELS

BECOMING ACQUAINTED with basic wiring methods will enable you to tackle a variety of electrical projects. In many cases, these include running cable through walls or between floors, connecting receptacles and switches to the system, and installing new circuits—the subjects covered in this chapter. For the basics, including an explanation of the workings of the home electrical system and the tools and equipment used in residential wiring, review the material in Part II, which begins on page 254.

FUSE AND CIRCUIT BREAKER CAPACITIES

BASIC CIRCUITRY

Charting Circuits

Whether working with fuses or circuit breakers, you must know which switches, receptacles, fixtures, or equipment are on the circuits they control. You must also know how they work. There are many types of fuses and circuit breakers, each with its own function. The purpose of fuses and circuit breakers is to protect the wiring—not the appliance. Keep this in mind as you chart circuits, verifying that no fuse or circuit breaker has more amperage than the wire it is protecting. The maximum allowable current a wire can carry, measured in amps, is called its ampacity.

While you are inspecting your fuse box or breaker panel, look for any obvious problems. For example, if you unscrew a fuse from a fuse box, examine both the fuse and its screw shell. (To be safe, first pull the main fuse.) Check the fuse or the screw shell for any damage from arcing or burning.

Once you are certain that there is no damage to your fuse box or breaker panel, you may begin to chart your circuits. A plug-in radio will come in handy, as will an assistant, if you can find one. If necessary, you can do the work alone—it will just take a bit longer.

CHARTING CIRCUITS

Identifying which circuits service all the receptacles, switches, lights, and appliances in your house takes some time. And it works best if you do it with a helper, so you’ll have to draft someone for the afternoon and expel everyone else so things are quiet. The time and effort you spend on this job, however, are well worth it. By knowing which breaker controls which device, you can quickly turn off power to anything you are working on and avoid the risk of serious shock.

TOOLS & MATERIALS

Felt tip marker

Stick-on labels

Graph paper

1 Before you label anything in your service panel box, make a scaled drawing of every room in your house. Draw the location of all the receptacles, light fixtures, switches, and appliances, and note where all the cabinets and furniture are positioned.

2 Once all the circuits are identified, go to the service panel and mark which breakers go to which circuits using stick-on labels. Then test each circuit by turning off the power, plugging in a radio (that’s turned on) to any given outlet, and then turning the power on at the panel to see if the radio plays.

3 If you are working by yourself, adjust the radio to a high volume so that when you turn on the power you can hear from the service panel area if the radio comes on.

4 As you go from outlet to outlet, note on your room drawings which ones occupy which circuits. You’ll need help to check if lights and ceiling fans turn on when you switch the breakers.

5 You will also need help from someone to check any appliance circuits. To do this with a range, for example, first turn off the breaker; then have a helper turn on the range. Next, turn on the breaker and see if the range comes on.

CHECKING FOR DAMAGE

You can easily diagnose a blown fuse element by looking through the fuse glass. A burned element suggests an overload; a broken element and darkened glass suggests a short circuit.

When a plug fuse is blown, the fuse shell may also be damaged. Check it for signs of burning and arcing.

A damaged plug fuse will clearly show marks caused by burning and arcing.

Burn flashes in a circuit breaker panel are a telltale sign of serious damage.

DESIGNING A KITCHEN WIRING PLAN

A WIRING PLAN must accommodate lighting fixtures, outlets for small appliances, and other devices that are often moved from one area to another, and outlets for large permanent appliances, such as dishwashers, washing machines, and electric ranges.

Creating the Plan

A kitchen probably requires the most complicated plan. For clarity and ease of viewing, we’ve provided two wiring diagrams: one for small-appliance outlets and the other for general lighting outlets. The National Electrical Code defines a general-purpose branch circuit as a circuit that supplies two or more receptacles or outlets for lighting and appliances. An appliance branch circuit is a circuit that supplies energy to one or more outlets to which appliances are to be connected and that has no permanently connected lighting fixtures that are not a part of an appliance.

As a minimum, Section 210.52(B) of the NEC requires that the dining room, pantry, and kitchen, including countertop receptacles, be supplied by no less than two 20-ampere branch circuits. Remember, the NEC provides the minimum requirements. It is recommended that more than two circuits be provided for these areas. However, these circuits are allowed to also supply the other receptacles in the dining room, pantry, and kitchen.

Gas ranges, such as the one shown here, require a 15-amp circuit to control clocks, burner ignition devices, and lights. For electric ranges, use a 50-amp range receptacle placed on a dedicated circuit.

SMALL APPLIANCE BRANCH CIRCUITS

Countertop Receptacles. Place receptacles so that kitchen appliances supplied with 2-foot power cords, such as toasters, coffee makers, and electric griddles, can reach a receptacle without the use of an extension cord. For example, there must be a receptacle within 2 feet of the end of the counter. There must be a receptacle within 2 feet from each end of the sink. The maximum distance between receptacles is 4 feet. Therefore, if an appliance is placed between the receptacles, the 2-foot cord can reach either receptacle. The spacing around an inside corner is measured on the top of the counter along the wall line.

GFCI Protection. To protect users of kitchen appliances in the vicinity of water, Section 410(A)(6) requires all kitchen countertop receptacles to be provided with ground-fault circuit-interrupter (GFCI) protection, regardless of how far they are located from the sink. Provide GFCI protection by one of two methods. Either install a GFCI receptacle as the first one in the circuit and connect regular receptacles to the load side of the GFCI, which will protect those receptacles downstream, or install a GFCI circuit breaker to protect the entire circuit.

Lighting. You will notice in the wiring diagram that there are no lighting outlets on the 20-ampere small appliance branch circuits. Lighting should be provided by 15-ampere circuits. Arrange the lighting circuits in such a manner that should one circuit fail, the space will still be at least partially illuminated by lights on another circuit.

Plan on installing three-way switches in such a manner that lights can be turned on in the adjoining room before turning off the lights in the room that you are leaving. Should table or floor lamps be desired in the kitchen or dining area, install switch-controlled receptacle outlets that are supplied by a 15-ampere circuit.

GENERAL PURPOSE LIGHTING OUTLETS

MAXIMUM WIRES IN A BOX

CALCULATING AMPACITY

AN OVERLOADED CIRCUIT is a real danger in any electrical system and can easily lead to a blown fuse or tripped circuit breaker. Worse, it poses a potential fire hazard and can be a threat to both your life and property. The NEC requires that the demand on a given circuit be kept below its safe capacity (Section 220.14).

To calculate the total amperage of the circuit, add up those loads of which you know the amperage. For those loads that are listed in wattage instead of amperage, divide the wattage by the circuit voltage to get the amperage (amps = watts/volts), and add the values to the other amperage loads. Total amperage load for the circuit should not exceed the breaker or fuse rating. The safe capacity of a circuit equals only 80 percent of the maximum amp rating. For a typical 20-amp circuit, the circuit should carry just 16 amps. If you can’t find the amperage or wattage of the appliance, use “Appliance Wattage,” page 263.

This product label provides information about the amperage used by the device.

BASIC WIRING

Height and Clearance Requirements

New-construction wiring proceeds from a power or lighting plan. Use these floor plans to lay out what is known as rough-in work. This includes installing the outlet boxes, running the wiring through the rough framing, stripping the wires inside the electrical boxes, and connecting the grounding wires. Because the electrical inspector will review the construction site and approve or reject the rough-in wiring, it is necessary to follow NEC requirements when installing wiring and electrical fixtures.

Clearance requirements are especially important to reduce the potential for fire hazards. For example, recessed fixtures not approved for contact with insulation must be spaced at least ½ inch from combustible materials [NEC Section 410.116(A)(1)]. When locating receptacles and switches, adhere to specific height requirements both for reasons of safety and accessibility. Switches, for instance, are not permitted to be any higher than 6 feet 7 inches above the floor or working level (Section 404.8).

INSTALLING ELECTRICAL BOXES

BOTH FOR EASE OF USE and aesthetics, receptacle and switch boxes should be kept at a uniform height above the finished floor or work surface. A general rule of thumb is to center receptacle boxes 12 inches above the floor—18 inches for handicapped accessibility. Center receptacle boxes over countertops 4 feet above the finished floor, as well as receptacle boxes in bathrooms and garages. Laundry receptacles are placed at a height of 3 ½ feet. Switch boxes, on the other hand, are normally centered 4 feet above the finished floor—the maximum for handicapped accessibility.

A common type of electrical box used in residential work today is a nonmetallic (plastic or fiberglass) box that may include integral nails for fastening it to stud framing. Nonmetallic boxes such as this are inexpensive and easy to install. You place the box against a stud, bring the face of the box flush to where the drywall will be after it is installed, and then nail the box in place. Be sure to purchase boxes that have enough depth—at least 1 ¼ to 1 ½ inches. This will give you approximately 23 cubic inches of interior box volume in which to tuck your wires. Using cable staples, secure the nonmetallic cable no more than 12 inches from the single-device electrical box. Make sure that at least ¼ inch of fully insulated cable will be secured inside of the box after the wires are stripped. Many switch boxes have gauge marks on their sides that allow you to position the box on a framing stud without having to measure depth. Recess boxes no more than ¼ inch from the finished wall surface. Mount boxes flush with the surface of combustible materials, such as wood.

Another type of electrical box is the handy box: a single-switch/receptacle box that is often screwed directly to a framing member, using a portable electric drill with a screwdriver bit. They sometimes come with a side-mounting flange to aid in installation. One danger, however, is that most handy boxes do not have adequate depth and can, therefore, only accommodate one cable safely. Misuse of this type of box is a code violation and should be avoided.

On masonry surfaces, attach boxes using masonry anchors and screws. Simply drill anchor holes in the masonry; then insert the anchors, and mount the box.

Receptacles should be centered 12 in. above the finished floor—18 in. for handicapped accessibility. Receptacles over countertops should be centered 4 ft. above the finished floor. Switches are generally centered at this same height, which is the maximum for handicapped accessibility.

STRIPPING WIRES AND CABLES

There are many different ways to strip electrical cable, but probably the easiest is to use a combination of a cable ripper to peel off the plastic sheathing, followed by a multipurpose tool or wire strippers to remove the insulation on the wires. Most boxes require that about 8 inches of cable wire extend into the box. So strip off 8 inches of sheathing first; then take off about ⅝ inch of insulation from the end of each wire. Slide this cable into the box, and attach the outlet device.

TOOLS & MATERIALS

Multipurpose tool

Cable ripper

Cable

1 To remove the plastic sheathing from an electrical cable, use a cable ripper. Slide this simple tool over the end of the cable; then squeeze the halves together to pierce the sheathing (top). To cut the sheathing, pull the ripper to the end of the cable (above).

2 Once the sheathing is cut to the end of the cable, pull back the sheathing to where the cable was first pierced (top), and cut off the sheathing using a multipurpose tool or a utility knife at this point (bottom).

3 Use a multipurpose tool to strip the insulation from the ends of the wire. Take off about ⅝ in. of insulation, using the appropriate slot on the tool that matches the gauge of the wire.

Preparing for Inspection

Once new framing walls are ready to be wired and electrical boxes have all been put in place, carefully begin pulling the cable through the framing. When you insert a cable end into an electrical box, leave a minimum of 6 inches of extra cable, cutting away the excess. Using a cable staple, secure the cable at a maximum of 12 inches above the single-device box. After you have run all cables through the framing and into the electrical boxes, rip back and remove the sheathing from the cable ends in each box; then strip the individual wires. Before a rough-in inspection can be done, you must also splice together the grounding wires using either green wire connectors or wire crimping ferrules. Then place the wires securely in their boxes.

After a rough-in inspection is performed, install the receptacles and switches. Wait until the drywall is in place before doing this work. When the walls are completed and all of the boxes wired, you can install cover plates and turn on the power. Check each receptacle, using a plug-in receptacle analyzer, to verify that all of the wiring has been properly done. Install the light fixtures; then confirm that they are all working. Once you have completed all of this, your work will be ready for final inspection. The inspector will reexamine your work, performing many of the same circuit tests as you.

GRANDFATHERING EXISTING ELECTRICAL WORK

QUESTIONS SOMETIMES ARISE as to whether it’s necessary to update a certain electrical issue, or what wiring conditions will or won’t be flagged in a home inspection report. When you are unsure what is permitted and what is not, your local building department is a great source of knowledge, especially if your work to be completed will require a permit, which means an inspection. But before the permit comes the plan review where you can find out if your ideas are correct, or if you need someone with a specific license to do the work.

Most home improvement jobs can be accomplished by the do-it-yourselfer homeowner, with exceptions for plumbing, gas piping, and heating. In these areas, municipalities have found it best to have licensed contractors perform the work to ensure uniformity and public safety. That is, after all, the goal of the permit process—uniformity and public safety no matter who performs the work. Plans, permits, and inspections go a long way to keeping everyone safe and healthy in your community. And keep in mind that the goal of the National Electrical Code (NEC) is to ensure a safe, reliable electrical system inside your home—for your own protection.

Grandfathering as used in the building industry refers to cases where an outdated building method is permitted to remain in place as long as that area of a home or building does not require repair, renovation, or demolition. If the area is going to be repaired, renovated, or demolished, then it—along with any new parts or construction—must meet current building codes for that community.

There are many 100-amp services provided to homes across America that still have fuses to control a dryer circuit, or have receptacles with only two prongs without the third ground prong. Are they as safe as the state-of-the-art circuit breakers for a dryer, or a grounded receptacle connected to a GFCI breaker? Of course not. But are they legal? Under grandfather clauses, yes, they are.

The real estate industry across America has become very competitive, and the best-kept homes, sometimes regardless of location, can at times bring very high sale prices and sell in the blink of an eye. This is where the home inspection industry comes into play. Inspectors look at the current conditions in a home, and find potential issues due to the home’s age, and list their concerns for the perspective buyer. It is then up to the seller and the buyer to negotiate what gets fixed and who pays for it. But in the pandemic-era market, the demand for housing is so high that some homes are being bought without any home inspections. Still, if you as a buyer have the opportunity to require a home inspection, it’s always in your best interest to do so.

This is just one example of grandfathered outdoor receptacle covers still in use today.

ATTIC AND CRAWL SPACE RUNS

Attic Runs. To run cable perpendicular to framing joists in an unfinished attic, construct a channel space along an edge wall, using two 1x4 furring strips as guard boards, as shown. You can also drill holes through the middle of the joists and run the cable through these holes. This option is a poor choice if insulation is in the way.

Crawl Space Runs. To run cable perpendicular to framing joists in an unfinished basement or crawl space, construct a runway using a 1x4 furring strip along the bottom edge of the framing or bore holes in the joists. You can staple cable containing three 8-gauge conductors or larger directly to the underside of the joists.

smart tip

SPLICING GROUNDING WIRES

IN EXISTING WIRING YOU’RE LIKELY TO COME ACROSS THE PIGTAIL METHOD OF SPLICING GROUNDING WIRES (IN THE PHOTO AT RIGHT), SO THAT’S THE METHOD DEMONSTRATED THROUGHOUT THIS BOOK. HOWEVER, GROUNDING WIRE CONNECTORS ARE MANUFACTURED WITH A HOLE AT THE TOP SO THAT WIRES CAN BE SPLICED AS SHOWN AT FAR RIGHT. THIS IS THE METHOD ACTUALLY PREFERRED BY ELECTRICIANS THESE DAYS.

When multiple ground wires are present in a junction box, a copper crimp sleeve is used to trim all ground wires except the one(s) necessary to connect to the device ground screw.

INSTALLING A JUNCTION BOX

No wire splices outside an electrical box are permitted by the NEC. But this doesn’t mean that they don’t occur, particularly in old houses that have suffered at the hands of sloppy or uninformed electricians. If you have any of these splices in your house, you must take apart the existing splice; install a junction box; make the new splices using wire connectors; and cover the box with a protective metal cover plate. For descriptions of the parts and tools used in this project, see pages 278 and 279. For an in-depth tutorial on splicing wires together, see page 291.

TOOLS & MATERIALS

Insulated screwdrivers

Multipurpose tool

Hammer

Neon circuit tester

Wire connectors

Screws/nails

Grounding pigtail and screw

Junction box

Cable clamps

Cable

1 Turn off the power to the circuit with the splice in the cable. Remove any wire connectors or electrical tape from the wires. Then check for any power with a neon circuit tester. If you find power, immediately locate the proper circuit breaker and turn it off.

2 For the wires to have access to the junction box, remove a couple of knockout plates using a screwdriver and a hammer. Then separate the splices, and install the box so it falls midway between the ends of both cables. Screw or nail the box in place (inset).

3 Put cable connectors into both knockout openings; then slide the cables through the connectors; and tighten the cable clamps onto the cable. Finish up by turning the locknuts onto the connectors from inside the box. Secure these nuts using slip joint pliers.

4 Connect a length of grounding wire to the green grounding screw inside the box (inset). Then splice all the like-colored wires in the box using the proper wire connectors for the wire gauge in the cable. Red-colored connectors usually work for both two 14-gauge wires and two 12-gauge wires. Green connectors are used for ground wires.

5 Carefully push all the spliced wires into the junction box, and install the box cover plate. Turn on the circuit power at the breaker panel, and check to see if all the receptacles, switches, and lights on the circuit are working properly.

SURFACE WIRING

CONDITIONS EXIST where concealed wiring isn’t possible—for example, a basement having exposed concrete or masonry walls. In this case, surface wiring is the only option. Surface-mounted conduit, or raceway, provides a rigid flat metal or plastic pipe to convey wire across instead of inside a wall or ceiling. Special receptacle and fixture boxes are used in conjunction with raceway to offer a safe way to install surface wiring. A plastic raceway requires a separate grounding wire; a metal raceway connected to a properly grounded electrical box is self-grounding. (See “Raceways,” page 311.)

Raceway channels protect exposed wire along a wall or ceiling surface.

RUNNING CABLE THROUGH FRAMING

INSTALLING WIRING through new construction is relatively easy. The most common electrical installations are those in which outlet boxes are mounted alongside a stud or joist, although this is not always possible. Once electrical boxes are in place, run the cable through the framing members. Do this by drilling ¾-inch holes directly through the center of the studs or joists. Center the holes at least 1 ⅝ inches in from the edge of the framing member. If you must drill closer, then attach a wire shield to the outer edge of the framing to prevent nails or screws from penetrating the hole and causing damage to the cable during the course of future work.

If you cannot drill holes through framing because the framing cavity contains ductwork or plumbing, you may have to resort to surface wiring to do the job properly. (See “Surface Wiring,” page 21.)

Avoiding Damage. Be careful not to jerk the wire cable violently as you pull it through the drilled holes in the framing. The friction from pulling cable through roughcut wood can cause the cable sheathing to tear, exposing the wires to serious damage. You should also avoid making sharp bends or kinks in the cable, as these too can damage the wiring. In addition, be careful when running cable along the bottom of a wall—there are likely to be toenailed fasteners near the bottom of each wall stud.

Getting around windows and doors can also be a problem. If there are cripple studs above the header, then you can drill holes through them for cable. However, you can’t drill through the length of a solid-wood header. If possible, you can go over or under such obstacles. As a last resort, use a router to cut a channel deeply enough across the surface of the header to accommodate a cable; protect the cable by installing metal plates over it.

Holes and Notches. If you bore holes through ceiling and floor joists, the holes must be located so that they will not undermine the structural integrity of the framing. (See illustration below.) This is also a concern if you notch the wood along the top or bottom edge to run cable perpendicular to the joists. In this instance, you must install metal wire shields to protect the cable from damage. Even cable that runs parallel with framing should not be left vulnerable or hanging loosely in a wall or floor space. Use cable staples to secure it in place along the center of the stud, joist, or rafter.

A bored hole must clear the edge of a framing stud by at least 1 ¼ in. A ¾-in. hole, for example, must be centered at least 1 ⅝ in. in from the outer edge of a wall stud. If the hole edge is closer to the stud edge than this, it must be protected by a metal wire shield (NEC Section 300.4).

Allow the cable to sag or curve slightly, rather than pulling it tightly through a stud wall, to prevent potential kinks, sharp bends, or overstretching of the wire. When drilling holes near the soleplate of a stud-framed wall, steer clear of toenailing and other metal fasteners that may snag your drill bit.

Cripple studs, left, over a header offer a simple and convenient path for wiring around a door or window opening. The best way to go around a solid header, right, is to run your wiring through the ceiling joists above or the floor joists below the rough opening.

smart tip

ROUTING A SOLID HEADER

USE A ROUTER TO CUT A CABLE CHANNEL ACROSS A SOLID HEADER ONLY IF YOU HAVE NO OTHER ALTERNATIVE. ATTACH A SERIES OF METAL PLATES (SHOWN AS CUTAWAY, BOTTOM) OVER THE ROUTED CABLE CHANNEL TO PROTECT THE CABLE FROM POTENTIAL NAIL DAMAGE.

Opening and Closing Walls

Running cables through existing walls and joist spaces is a lot more complicated than running cables in new construction. Because you cannot see into finished framing cavities, fishing cables through walls and ceilings requires great patience and more than a little skill.

If you have access to walls from a basement or attic, you can get power into walls by fishing the cable vertically instead of horizontally through the structural framing. In many cases, running cable the long way around to complete a circuit may be the easiest route, even if you have to spend more money for cable. The cost of the cable is likely to be much less than that of ripping into walls and ceilings. If you must run cable across existing framing, for example, you may have to cut into drywall in order to position the cable properly. It is a good idea to take time initially to explore alternative routes the cable might follow. Try to determine the best route; then make a rough sketch or map of the cable route. This will undoubtedly save you time and money later.

Before running cable, first decide where to locate your new switch, outlet, or junction box; then determine which walls or ceilings, if any, need to be opened to efficiently route the cable to this point. You can cut openings in drywall using a utility knife, mini-hacksaw, or keyhole or saber saw. After you make your cut, either remove the scrap or knock it back between the framing members.

In an unfinished basement, you may encounter hollow concrete-block walls or poured steel-reinforced solid concrete walls. Although it is possible to cut into a hollow concrete block wall, it isn’t practical. For block and concrete walls, it is best to install metal surface raceways or electrical conduit, and surface-mount your electrical boxes and wiring. Use a masonry bit on your power drill to make pilot holes for masonry anchors; then anchor the boxes and conduit clamps directly to the wall.

Flat square electrical boxes are specially made to fit in shallow furre-dout wall cavities. A–shallow boxes; B–box extension; C–box cover

FISHING CABLE FROM BELOW THE FLOOR

Fishing cable through closed walls can be difficult. Here are some tips to make it easier: always use a cut-in box for the outlet; use a guide wire to establish one reference point for two different floors; be willing to waste some wire by running the cable into the basement and then to its destination, instead of taking the shorter, but usually much harder, route through the wall.

TOOLS & MATERIALS

Keyhole or saber saw

Cordless drill

⅛-inch bit

¾-inch spade bit

Fish tape

Guide wire

1 Trace the outline of a cut-in box on the wall, and cut along this line using a drywall or keyhole saw (inset). Then drill a small hole through the floor directly below this box opening in the wall.

2 Use a piece of scrap wire as a guide to locate the hole under the floor. Just slide the wire into the hole; go downstairs and find the wire. Because the hole was drilled right next to the wall, the wall framing should begin about ½ in. away from the guide wire.

3 Estimate that the middle of the wall’s sole plate is about 2 in. away from the guide wire. Mark this centerline along the bottom surface of the floor plywood.

4 Using a drill with a ¾-in. spade bit, bore a hole up through the plywood and wall plate. Unwind some cable from the roll, and push the free end up through this hole. Be sure to push up enough cable to reach the box hole. Tape the cable in place so it doesn’t fall out of the hole.

5 If you can fit your hand into the box hole, reach in and grab the cable. If not, get some help from someone with smaller hands. Once you pull the cable out, install it in a cut-in box; then push the box into the wall, and secure it in place.

RUNNING CABLE BEHIND A BASEBOARD

One of the best places to run new cable in a finished room is to remove the baseboard and install the cable in the stud space behind. The job isn’t very hard, and you can make it even easier by being careful when you remove the baseboard. By reusing the old baseboard, you can save some money, but more importantly, you can save a lot of time and effort.

TOOLS & MATERIALS

Pencil

Utility knife

Metal paint scraper

Wood chisel

Straightedge

Backsaw

Hammer

Finishing nails

Drywall nails

Nail set

Fish tape

Wire shields

Measuring tape

Wood shim

Cable

Paintbrush and paint

1 Installing cable behind a baseboard is one of the best ways to route cable through existing walls. The first step is to mark the wall along the top of the baseboard (top). Then cut along the joint between the baseboard and the wall to break the seal made by caulk and paint (bottom).

2 Carefully pry off the baseboard using a putty knife and a shimming shingle. Work the knife blade between the two, and pry them apart enough to slide the shingle behind the knife. The shingle protects the wall surface from damage.

3 Measure down from the wall reference line ½ in., and mark the wall every couple of feet. Using a long straightedge and pencil, draw a cut line through these marks.

4 Use a utility knife or a keyhole saw to cut through the drywall along the cut line. Once the piece is free, pull it away from the wall. If the drywall was screwed in place, remove the screws so the piece of drywall comes out cleanly and can be reused.

5 The cable can run either in notches cut in the edge of the studs, as shown here, or in holes drilled through the middle of the studs. If you notch the studs, install a metal shield on each stud to protect the cable.

6 Once the cable is entirely installed, cover up the opening with the piece of drywall you removed, if it’s still useable, or with a new piece. Drive the nails or screws in the studs and bottom plate to avoid hitting the metal shields.

7 Reinstall the old baseboard, or cut and install a new baseboard that matches the other trim in the room. Then caulk the joint between the baseboard and the wall, and paint the joint and the baseboard.

smart tip

WIRING AROUND AN EXISTING DOORWAY

IF AN EXISTING DOORWAY IS IN THE PATH OF YOUR CABLE, YOU WILL HAVE TO RUN THE CABLE UP AND AROUND THE DOOR FRAME. IN THIS SITUATION, RATHER THAN CUTTING OUT SECTIONS OF THE DRYWALL, YOU MAY BE ABLE TO TAKE ADVANTAGE OF THE SHIM SPACE. REMOVE THE MOLDING FROM AROUND THE DOOR, GENTLY PRYING IT AWAY FROM THE WALL. USE A RIGID PAINT SCRAPER WITH A SCRAP PIECE OF WOOD UNDER IT TO PROTECT THE WALL. IF YOU CANNOT REMOVE THE TRIM WITHOUT CAUSING IT DAMAGE, YOU MAY HAVE TO REPLACE THE MOLDING. IF THE MOLDING IS IRREPLACEABLE, YOU MAY WISH TO RECONSIDER USING THIS METHOD TO ROUTE THE CABLE AROUND YOUR DOOR. ONCE THE SHIM SPACE IS EXPOSED, NOTCH OUT THE SHIM SPACERS JUST ENOUGH TO ACCOMMODATE THE CABLE. STRING THE CABLE AROUND THE SHIM SPACE; THEN COVER THE NOTCHED AREAS, USING METAL WIRE SHIELDS.

FISHING CABLE ACROSS A CEILING

Running cable through an existing but inaccessible ceiling may require that you cut both a ceiling and a wall opening in order to fish the cable from a vertical wall cavity to a horizontal ceiling cavity. Once the ceiling is opened, use a fish tape to get the cable across to the new electrical box.

TOOLS & MATERIALS

Stepladder

Utility knife

Keyhole or saber saw

Wood chisel

Pencil and straightedge

Plumb bob

Hammer

Cordless drill

¾-inch spade bit

Electrical tape

Nonmetallic fish tape

Wire shields

Safety glasses

Dust mask

1 Determine where you want your ceiling outlet; then trace around the fixture box. Using a drywall or keyhole saw, cut along the line and remove the drywall. Then trace around the fixture box or use the manufacturer’s paper template supplied with many old work/remodel plastic electrical boxes.

2 Measure from the end wall of the room to the ceiling hole. Then go to the side room wall and transfer this measurement to the corner between the wall and ceiling.

3 Cut a 2-in.-wide by 6-in.-long opening in the ceiling and the wall. Use a utility knife to cut the wall opening because the top plates are behind it. Use a keyhole saw for the ceiling.

4 Using a sharp chisel and a hammer, cut a ¾-in.-wide by 1-in.-deep notch in the wall plates. This notch will act as a raceway for the electrical cable that will service the ceiling fixture. If you run into a nail, stop chiseling and cut it out with a hacksaw to prevent more damage to the chisel blade.

5 Use a fish tape to pull cable into the box. Start by feeding the tape into the ceiling hole, directing it through the access hole in the ceiling and down to the box hole near the floor.

6 Tape the end of some electrical cable to the end of the fish tape, and pull the cable up through the box hole at the floor.

7 Gently pull the cable through the access hole and the outlet hole in the ceiling. Cover the cable at the top plates notch with a metal shield.

If removing your existing baseboard is not a reasonable option (see page 26), you will simply have to cut out a limited section of visible drywall in order to gain access to the stud framing. The resulting wall damage can probably be minimized if you use a specialized flex-drill—one that is long and flexible—to bore through several adjacent framing studs, rather than having to notch them all at the wall surface. Nevertheless, some patching and repair work, as well as refinishing, will still be necessary. (The long section of drywall in this photo has been removed for clarity.)

FISHING WIRE THROUGH A WALL

Another way to run cable across a wall is to make several cutouts in the drywall to expose the stud framing, and bore holes through the studs. Fish the cable gradually from the existing box to the new location.

RECEPTACLES

Duplex Receptacles

Although there are two basic types of receptacles—single and duplex—only duplex receptacles are commonly found in modern homes. A duplex receptacle accommodates two plugs at the same time. Originally, receptacles were neither grounded nor polarized; later, they became polarized but not grounded. Today, receptacles include a screw terminal for a grounding connection. These receptacles have a total of five terminal screws: two brass screw terminals on the right side for black/red hot-wire connections; two silver screw terminals on the left side for white neutral-wire connections; and one green screw terminal on the left side for a bare copper or green grounding-wire connection. The NEC now requires that in new construction all 125-volt, 15- and 20-amp receptacles installed in living areas must be listed as tamper-proof. (See “Tamper-Proof Receptacles,” page 307.) Check with your building department for requirements in your area.

Receptacle, right side. The hot black or red wires are connected to the brass terminal screws on a receptacle.

Receptacle, left side. The silver terminal screws on a receptacle receive the white neutral wires, while the green terminal screw receives the grounding wire.

RECEPTACLE HISTORY

Early receptacles had two non-polarized connections (A). For this type of receptacle, the colored wires could go to either screw terminal. Later, manufacturers made polarized receptacles (B). These require that a specific color wire be connected to a specific screw terminal, but they are not grounded. Today, receptacles also include a green grounding screw terminal (C).

INSTALLING USB/120-VOLT DUAL-PURPOSE RESIDENTIAL RECEPTACLES

THESE RECEPTACLES ARE AVAILABLE in both 20-amp and 15-amp 120-volt receptacles in the Decora style cover plate that will provide the required 3.6-amp USB charging current for your electronic devices. The advantage is the adapter plug to convert your USB cable to the 3-prong outlet is no longer necessary in the event it gets lost or broken. To meet the latest NEC requirements, these dual-purpose receptacles are being produced in the tamper-proof style to prevent accidental electrical shock to children.

Be sure to match the amperage of the receptacle to the amperage of the branch circuit breaker or fuse. To begin, disconnect the power to the receptacle by locating the relevant fuse or breaker in the panel box. Test the receptacle by plugging in a device to be sure the power is disconnected. With the grounding lugs facing the same way, up or down, detach one wire at a time, and connect each wire to the matching screw terminal on the dual-purpose receptacle.

New dual-use receptacles support back wiring as shown in the figures above. Back wiring results in the fastest, highest quality connection, but the device will also support side wiring under the connection screws. Follow the strip wire gauge on the back for proper length to assure the best connection.

Fasten the device screws to the junction box and install the Decora cover plate with the two supplied cover plate screws. Complete the installation by restoring power to the branch circuit and test the receptacle with an electrical device.

WIRING AN END-OF-RUN RECEPTACLE

An end-of-run receptacle is one of the easiest devices to install. Because only one cable comes into the box, there’s only one black (hot) wire, one white (neutral) wire, and one bare ground wire. Just hook the black to a brass terminal, the white to a silver terminal, and the ground wire to the receptacle’s grounding screw.

TOOLS & MATERIALS

Insulated screwdriver

Diagonal cutting pliers

Long-nose pliers

Wire stripper

Multipurpose tool

Cable ripper

Duplex receptacle

Receptacle box

1 2/2G NM cable

Green wire connector

Grounding pigtail and screw (for metal boxes)

Cable clamps (for metal boxes)

1 Pull about 8 in. of cable into the box to allow enough wire to easily attach the receptacle (inset). Strip off most of the cable sheathing; then strip the insulation from the ends of both wires.

2 Using long-nose pliers, form a small hook on the ends of the cable wires. Then loop the hook around its terminal screw and tighten it in place. The white wire goes on a silver screw. The black wire is attached to a brass- or gold-colored screw.

3 Attach the grounding wire to the receptacle’s grounding screw. Once all the wires are attached, push the receptacle into the box, and attach the receptacle to the box using screws. Add a receptacle cover and the job is done.

WIRING A MIDDLE-OF-RUN RECEPTACLE

The conventional way to wire a middle-of-run receptacle is to connect all of the wires to the receptacle, letting it act as the splice between the connecting black or white wires. Wiring a receptacle this way is easy but connects all of the devices on the circuit in series—if you temporarily remove one receptacle, the current to the rest of the line will be cut. As an alternative, wire the receptacles on the circuit independently. Splice each pair of hot and neutral wires using wire connectors; then connect a pigtail from each splice to the appropriate receptacle terminal. Only current drawn by the appliance plugged into it will flow through the receptacle. If you remove the receptacle from the circuit, the rest of the circuit will continue to work. This type of connection is necessary where three or more cables must be spliced together because more than one wire is not permitted under a single screw terminal.

TOOLS & MATERIALS

Insulated screwdriver

Diagonal cutting pliers

Long-nose pliers

Wire stripper

Multipurpose tool

Cable ripper

Duplex receptacle

Receptacle box

1 2/2G NM cable

Green wire connector

Grounding pigtail and screw (for metal boxes)

Cable clamps (for metal boxes)

This type of connection, using a metal box, allows the receptacles on a circuit to be wired independently.

1 Pull the cable through the box cable clamps until 8 in. of both cables are in the box (inset). Strip away the cable sheathing; then the insulation from the ends of the wire.

2 Make small hooks on the ends of all the wires using long-nose pliers. Then attach the wires to the receptacle by tightening a terminal screw against each wire.

3 Join both grounding wires with a grounding pigtail inside a wire connector. Attach the other end of the pigtail to the grounding screw on the receptacle.

Sequential 120-Volt Duplex Receptacles

Start- or middle-of-run receptacles are connected to all wires from both directions. End-of-run receptacles are the last on the circuit and have only two terminations and a ground connection.

Multiple 120-Volt Duplex Receptacle Circuit

On multiple 120-volt receptacle circuits, three-wire cable is used to connect all but the last receptacle. The white neutral wire is shared by both circuits.

WIRING A SPLIT-CIRCUIT RECEPTACLE

The metal tabs connecting the screw terminals on each side of a receptacle can be removed. By breaking the connection between the brass screw terminals you can wire the top outlet of the receptacle independently from the bottom. The silver tabs are normally left intact. This permits two appliances in a single receptacle to be powered by different circuits.

TOOLS & MATERIALS

Insulated screwdriver

Diagonal cutting pliers

Long-nose pliers

Wire stripper

Multipurpose tool

Cable ripper

Duplex receptacle

Receptacle box

1 2/3G NM cable

Green wire connector

Grounding pigtail and screw (for metal boxes)

Cable clamps (for metal boxes)

smart tip

AVOID PUSH-IN TERMINALS

SOME RECEPTACLES HAVE WIRE HOLES INSTEAD OF SCREW TERMINALS. ON THIS TYPE OF RECEPTACLE, THE END OF EACH STRIPPED WIRE (14-GAUGE COPPER ONLY) IS PUSHED INTO THE APPROPRIATE HOLE TO COMPLETE THE CONNECTION. ALTHOUGH SIMPLE TO USE, THESE KINDS OF CONNECTIONS CAN BE PROBLEMATIC AND ARE NOT RECOMMENDED.

1 Removing the tab connector between the brass terminal screws by breaking it away with long-nose pliers. This allows you to wire outlets on a duplex receptacle independently.

2 Once the tab has been removed, attach the two hot wires to the brass terminal screws. Don’t remove the tab that joins the silver screws. Just attach the white (neutral) wire to either silver screw.

3 Attach the grounding wire to the grounding screw on the receptacle. Then push the receptacle into the box; attach it with screws; and install a cover plate.

WIRING A SWITCH/RECEPTACLE

Combine a grounded receptacle