Other Books of Interest Croft, Summers • AMERICAN ELECfRICIANS' HANDBOOK Denno • ELECfRIC PROTECI1VE DEVICES Johnson • ELECfRICAL CONTRACI1NG BUSINESS HANDBOOK Johnson • SUCCESSFUL BUSINESS OPERATIONS FOR ELECfRICAL CONTRACTORS Kolstad • RAPID ELECfRICAL ESTIMATING AND PRICING Kusko • EMERGENCY/STANDBY POWER SYSTEMS Linden • HANDBOOK OF BATTERIES AND FUEL CELLS Lundquist ON-LINE ELECfRICAL TROUBLESHOOTING McPartland· MCGRAW-HILL'S NATIONAL ELECfRICAL CODE~ HANDBOOK McPartland • McGRAW-HILL'S HANDBOOK OF ELECTRICAL CONSTRUCI10N CALCULATIONS McPartland· HANDBOOK OF PRACTICAL ELECfRICAL Pete • ELECTRIC POWER SYSTEMS MANUAL Richter, Schwan • PRACTICAL ELECfRICAL WIRING Seidman, Mahrous, Hicks • HANDBOOK OF ELECfRIC Smeaton • SWITCHGEAR AND CONTROL HANDBOOK Traister· DESIGN AND APPLICATION OF SECURITY/FIRE DESIGN ELECTRICAL SAFETY HANDBOOK John Cadick, P.E Cadick Professional Services, Garland, Texas POWER CALCULATIONS ALARM SYSTEMS McGRAW-Hill, INC New York San Francisco Washington, D.C Auckland Bogota Caracas Lisbon London Madrid Mexico City Milan Montreal New Delhi San Juan Singapore Sydney Tokyo Toronto Library of Congress Cataloging.in·Publication Cadick, John Electrical safety handbook / John Cadick p em Includes index ISBN 0-07-009514-0 (alk paper) Electric engineering-8afety measures I Title TK152.C22 1994 621.319'028'9-dc20 Data Industrial safety 94-13347 CIP Copyright © 1994 by McGraw-Hill, Inc All rights reserved Printed in the United States of America Except as permitted under the United States Copyright Act of 1976, no part of this publication may be reproduced or distributed in any form or by any means, or stored in a data base or retrieval system, without the prior written permission of the publisher DOC/DOC 9098765 ISBN 0-07-009514-0 The sponsoring editor for this book was Harold B Crawford, the editing supervisor was Paul R Sobel, and the production supervisor was Pamela A Pelton It was set in Times Roman by North Market Street Graphics Printed and bound by R R Donnel/ey & Sons Company Information contained in this work has been obtained by McGrawHill, Inc., from sources believed to be reliable However, neither McGraw-Hill nor its authors guarantees the accuracy or completeness of any information published herein, and neither McGraw-Hill nor its authors shall be responsible for any errors, omissions, or damages arising out of this information This work is published with the understanding that McGraw-Hill and its authors are supplying information, but are not atfempting to render engineering or other professional services If such services are required, the assistance of an appropriate professional should be sought This book was printed on acid-free paper To my father, Ross M Cadick, who taught me how to work and to pursue excellence; my mother, Melba K Cadick, who taught me how to have fun; my wife, Sheryl Cadick, who taught me patience; my children, Ross, Anna, Jessica, and Julia, who have kept me young; and my friend, Thad Brown, who taught me how to business and still be kind to people CONTENTS Preface xi 1.1 Chapter Hazards of Electricity Introduction / 1.1 Hazard Descriptions / 1.1 Affected Body Parts / 1.9 Summary of Causes-Injury and Death Protective Strategies / 1.14 / 1.14 Chapter Electrical Safety Equipment 2.1 Introduction / 2.1 Flash and Thermal Protection / 2.1 Head and Eye Protection / 2.8 Rubber-Insulating Equipment / 2.11 Hot Sticks / 2.38 Insulated Tools / 2.42 Barriers and Signs / 2.43 Safety Tags, Locks, and Locking Devices / 2.46 Voltage-Measuring Instruments / 2.49 Safety Grounding Equipment / 2.57 Ground Fault Circuit Interrupters / 2.68 Safety Electrical One-Line Diagram / 2.70 The Electrician's Safety Kit / 2.72 Chapter Safety Procedures and Methods Introduction / 3.1 The Six-Step Safety Method / 3.1 Safe Switching of Power Systems / 3.3 Energy Control Programs / 3.21 Tagout-Lockout / 3.24 Voltage-Measurement Techniques / 3.30 Placement of Safety Grounds / 3.35 General Work Area Safety / 3.43 Tools and Test Equipment / 3.47 The One-Minute Safety Audit / 3.50 3.1 viii CONTENTS Chapter Regulatory and Legal Safety Requirements and Standards CONTENTS 4.1 Introduction / 4.1 The Regulatory Bodies / 4.1 The National Electrical Safety Code (NESC)-ANSI C-2 / 4.13 The National Electrical Code (NEC)-ANSIINFPA 70 / 4.15 Electrical Equipment Maintenance-ANSIINFPA 70B / 4.16 Electrical Safety Requirements for Employee Workplaces_ ANSIINFPA 70E / 4.17 The American Society for Testing and Materials (ASTM) Standards Occupational Safety and Health Administration (OSHA) Standards Chapter Safety Training Methods and Systems Introduction / 9.1 Elements of a Good Training Program / 9.3 On-the-Job Training / 9.6 Training Consultants and Vendors / 9.9 Training Program Setup-a Step-by-Step Method / 4.19 / 4.19 Index (follows Chapter 91 Chapter Accident Prevention, Accident Investigation, Rescue, and First Aid 5.1 Accident Prevention / 5.1 First Aid / 5.5 Rescue Techniques / 5.18 Accident Investigation / 5.39 Chapter Low-Voltage Safety Synopsis 6.1 Introduction / 6.1 Low-Voltage Equipment / 6.2 Grounding Low-Voltage Systems / 6.5 Safety Equipment / 6.14 Safety Procedures / 6.19 Chapter Medium- and High-Voltage Safety Synopsis Introduction / 7.1 High-Voltage Equipment / 7.1 Grounding Systems of over 1000 V / 7.3 Safety Equipment / 7.8 Safety Procedures / 7.12 Chapter Safety Management Structure 7.1 and Organizational Introduction / 8.1 Electrical Safety Program Development Employee Participation / 8.5 Safety Meeting / 8.6 Outage Reports / 8.8 Safety Audits / 8.8 8.1 / 8.1 ix 1.1 / 9.12 9.1 PREFACE Each year hundreds of people are killed and hundreds more are injured by electrical energy Many, if not most, of these deaths and injuries could be prevented by the use of appropriate electrical safety techniques and equipment The book was written as a reference for personnel working on or near electrical circuits of any voltage level Safety personnel, electricians, line workers, engineers, and supervisors will find the book to be an invaluable aid to safe and efficient work with electrical energy systems Management and safety training personnel will also find sections which aid them in the setup and implementation of organizational and training programs Chapter provides an overview of an often overlooked aspect of electrical safety-the nature of the hazard Many accidents could be prevented if personnel were simply made aware of how and why electricity is dangerous Chapters and present equipment and procedures that are used throughout the electrical industry The information in these two chapters can be used in the development of electrical safety programs for utility, industrial, and commercial electrical workers Chapter identifies both consensus and mandatory standards and standards organizations Referral to this chapter will provide the reader with information about the codes and standards which regulate the way that electrical work is performed Of course, the reader should always refer to the current versions of all of the standards which are described in Chapter Standards covered include the National Electrical Safety Code, the National Electrical Code, American Society of Testing and Materials, and other key publications and organizations Complete listings of some standards are included Chapter focuses on what to if an accident does happen Starting with a detailed description of accident prevention concepts, this chapter then provides the reader with information on rescue, first aid, and accident investigation The proper investigation of accidents is a science that should only be performed by qualified, experienced personnel Chapter describes what to do, and perhaps more importantly, what not to during an accident investigation Low voltage circuits can be just as deadly as high voltage circuits Chapters and define the key elements of electrical safety for low voltage and medium/high voltage circuits respectively Readers will be surprised at how little difference exists between low and mediumlhigh voltage safety Management often loses sight of its obligation in the provision of a safe work environment A well structured, safe work place goes beyond simply obeying the law Chapter describes the elements of a well structured, efficient electrical safety program Managers may refer to this chapter for direction during the setup and or modification of a company safety program Procedures, equipment, programs, and rules can never replace well trained, competent personnel Chapter presents information that will allow the setup, implementation, and evaluation of a successful electrical safety training program xii PREFACE CHAPTER This Electrical Safety Handbook presents, for the first time, a comprehensive guide to electrical safety equipment, procedures, training, and standards ACKNOWLEDGMENTS HAZARDS OF ELECTRICITY _ -~- The author gratefully acknowledges the following: Kathy Hooper, ASTM; Robert L Meltzer, ASTM; Laura Hannan, TEGAM, Incorporated; Raymond L Erickson, Eaton Corporation, Cutler-Hammer Products; H.G Brosz, Brosz and Associates Archives; P Eng, Brosz and Associates Archives; Ellis Lyons, W.H Salisbury and Co.; Tom Gerard, TIF Instruments, Inc., Miami, FL; LaNelle Morris, Direct Safety Company, Phoenix, Arizona; Tony Quick, Santronics Inc.; Ed DaCruz, Siebe North, Inc.; Benjamin L Bird, CIP Insulated Products; E.T Thonson, AVO Biddle Instruments, Blue Bell, PA; Terry Duchaine, Ideal Industries, Inc., Sycamore, IL; Mary Kay S Kopf, DuPont Fibers; Stephen Gillette, Electrical Apparatus Division of Siemens Energy and Automation, Inc.; Mary Beth Stahl, Mine Safety Appliances Company; Debbie Prikryl, Encon Safety Products; Craig H Seligman, NOMEX ® III Work Clothing, Workrite Uniform Company, Oxnard, CA; Kareem M Irfan, Square D Company, A.B Chance Co., AVO Multi-Amp Institute; Alan Mark Franks; and Sandy Young John Cadick INTRODUCTION Understanding the steps and procedures employed in a good electrical safety program requires an understanding of the nature of electrical hazards Although they may have trouble writing a concise definition, most people are familiar with electric shock This often painful experience leaves its memory indelibly etched on the human mind However, shock is only one of the electrical hazards There are two others-arc and blast This chapter describes each of the three hazards and explains how each affects the human body Understanding the nature of the hazards is useless unless protective strategies are developed to protect the worker This chapter also includes a synopsis of the types of protective strategies that should be used to protect the worker HAZARD DESCRIPTIONS Shock Description Electric shock is the physical stimulation that occurs when electric current passes through the body The effect that electric shock has on the body depends on the magnitude of the current flow, the body parts through which the current flows, and the general physical condition of the person being shocked Current Magnitude The magnitude of the current which flows through the body generally obeys Ohm's law, that is, where I = current magnitude, amperes (A) E = applied voltage, volts (V) R = resistance of path through which current flows, ohms (Q) In Fig 1.1 the worker has contacted a 120-V circuit when an electric drill shortcircuits internally The internal short circuit impresses 120 V across the body of the worker from the hand to the feet This creates a current flow through the worker to the ground and back to the source The total current flow in this case is given by the formula 1.1 Table 1.3 lists the effects that various currents will have on a 68-kilogram (kg) human being The current flow of 21.1 mA is sufficient to cause the worker to go into an "electrical hold." This is a condition wherein the muscles are contracted and held by the passage of the electric current-the worker cannot let go Under these circumstances, the electric shock would continue until the current was interrupted or until someone intervened and freed the worker from the contact Unless the worker is freed quickly, tissue and material heating will cause the resistances to drop, resulting in an increase in the current Such cases are frequently fatal Parts of the Body Current flow affects the various bodily organs in different manners For example, the heart can be caused to fibrillate with only 75 mA The diaphragm and the breathing system can be paralyzed, which possibly may be fatal, with less than 30 mA of current flow The specific responses of the various body parts to current flow are covered in later sections 1.4 CHAPTER ONE HAZARDS OF ELEcrRICITY TABLE 1.3 NominalHuman Response to Current Magnitudes' Current (60Hz)