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ELECTRICAL CONSTRUCTION DATABOOK is the allinone power tool you need to minimize construction risks and problems, avoid costly mistakes, work more efficiently, handle more projects without outside help, reduce waste, cut cost, and maximize profits. Applications expert Bob Hickey provides the exact data that lets you keep any commercial, industrial, or institutional electrical design and construction project on track and within budget. In this detailbydetail, quickreference sourcebook, Bob focuses on easytounderstand electrical system concepts, calculations, and code requirements that are most frequently encountered in a typical electrical system installation. You get a wealth of practical advice backed by hundreds of tables, sample calculations, charts, diagrams, and illustrations that will enable you to quickly and easily: Plan and design projects Determine space requirements for equipment installations Properly size equipment and distribution components Ensure adequate shortcircuit protection Provide proper overcurrent protection and coordination Comply with building codes and industry standards
Electrical Construction Databook Robert B. Hickey, P.E. McGraw-Hill New York Chicago San Francisco Lisbon London Madrid Mexico City Milan New Delhi San Juan Seoul Singapore Sydney Toronto Hickey_ FM 11/19/01 12:11 PM Page i Cataloging-in-Publication Data is on file with the Library of Congress Copyright © 2002 by The McGraw-Hill Companies, 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. 1234567890 PBT/PBT 0987654321 ISBN 0-07-137349-7 The sponsoring editor for this book was Larry Hager, the editing supervisor was Steven Melvin, and the production supervisor was Sherri Souffrance. It was set in New Century Schoolbook per the MHT design by Wayne A. Palmer of McGraw-Hill Professional’s Hightstown, N.J., composition unit. Phoenix Color/Book Technology was printer and binder. This book is printed on recycled, acid-free paper containing a minmum of 50% recycled, de-inked fiber. McGraw-Hill books are available at special quantity discounts to use as premi- ums and sales promotions, or for use in corporate training programs. For more information, please write to the Director of Special Sales, Professional Book Group, McGraw-Hill, Two Penn Plaza, New York, NY 10121-2298. Or contact your local bookstore. Information contained in this book has been obtained by The McGraw- Hill Companies, Inc., (“McGraw-Hill”) from sources believed to be reli- able. However, neither McGraw-Hill nor its authors guarantee the accuracy or completeness of any information published herein and nei- ther McGraw-Hill nor its authors shall be responsible for any errors, omissions, or damages arising out of use of this information. This work is published with the understanding that McGraw-Hill and its authors are supplying information, but are not attempting to render engineer- ing or other professional services. If such services are required, the assistance of an appropriate professional should be sought. McGraw-Hill Hickey_ FM 11/19/01 12:11 PM Page ii To Pat, my wife, whose love and support made this book possible Hickey_ FM 11/19/01 12:11 PM Page iii Introduction The Electrical Construction Databook provides the electrical design consultant, project manager, contractor, field superintendent, facility owners, and operations and maintenance personnel with a one-source reference guide to the most com- monly encountered (and needed) electrical design, installation, and application data. Valuable information ranging from NEC® installation requirements, wiring methods and materials, to lighting and telecommunications systems, with scores of topics in between, is included in this single easy-to-access volume. Numerous carefully selected sections of the National Electric Code (NEC®) are included with critical data and tables for sizing conductors, conduits, overcurrent protection, pull-boxes, etc., and many illustrations to help clarify the Code’s intent with regard to proper equipment installation, working clearances, acceptable installations under exceptions with certain conditions applied, and a plethora of others, including materials and methods. The Electrical Construction Databook contains single-line diagrams of primary and secondary service and system configurations, emergency and standby generator system configurations, and uninterruptable power supply system configurations, each with their advantages, disadvantages, and operating characteristics concisely outlined for easy comparison in determining what’s best for a given application. Even the sequence in which they are presented, in general, is from the least cost and reliability to the highest cost and reliability in order to broadly address the economic criteria. In addition to recognized code and professional organizations, much of the material in this book has been gleaned from manufacturer’s sources and trade association–supplied information; some of the manufacturer-supplied data may be proprietary in nature but generally is similar to products made by other vendors. And the reader should note that many manufacturers and related trade organi- zations are often eager to furnish additional and more specific information if requested. The Electrical Construction Databook conforms to the newly published 2002 edi- tion of the NEC®. There may be some minor subtext references that use the 1999 NEC® edition’s section/paragraph nomenclature and a few illustrations that show English units only without the equivalent metric units, but they are still valid, to the best of the author’s knowledge. This one-source Electrical Construction Databook should prove invaluable for office- and field-based construction and design professionals, since it contains, in one vol- ume, answers to so many of the design and application questions that arise before and during a construction project. As an electrical engineer who has worked in the trade as an electrician, I have tried, based on almost 40 years of experience in the construction industry, to blend together data and information that is useful and practical from both a design and construction installation perspective. I trust that I have met that goal. I hope you find the Electrical Construction Databook a worthwhile addition to your construction library. Bob Hickey Hickey_ FM 11/19/01 12:11 PM Page xxvii Credits Reprinted with permission from NFPA 70 (2002), the National Electrical Code®, copyright © 2001, National Fire Protection Association, Quincy, MA 02269. This reprinted material is not the referenced subject which is represented only by the standard in its entirety. Figures 4.4.25, 15.3.1–15.3.5, 17.1.14D, and 17.1.15A–D, and Tables 2.2.1, 2.5.1, 2.5.2, 4.1.0, 4.1.1, 4.2.1, 4.3.1, 4.4.1–4.4.24, 4.4.26–4.4.34, 4.5.1, 4.5.3–4.5.5, 4.7.1, 4.7.3–4.7.7, 4.7.9, 4.8.1, 4.8.2, 4.9.1–4.9.6, 9.1.11, 9.1.12, 10.1.2, 12.1.6, 12.1.7, 13.1.1, 13.2.5, 15.1.1–15.1.8, 15.2.1–15.2.8, 15.3.6, 15.4.1–15.4.24, 17.1.9, 17.1.10, 17.1.14, and 17.1.15 Reprinted with permission from the National Electrical Code® Handbook, copy- right © 1999, National Fire Protection Association, Quincy, MA 02269. This reprinted material is not the referenced subject which is represented subject which is represented only by the standard in its entirety. Figures 1.4.0, 1.4.1, 2.2.2–2.2.6, 2.3.1–2.3.5, 2.4.1–2.4.3, 4.2.2, 4.5.2, 4.5.6, 4.5.7, 4.6.1, 4.7.2, 4.7.8, 17.1.12A,B, 17.1.13, 17.1.14C–G, and 17.1.15E–H, and Tables 2.1.1, 2.1.2, and 4.4.3 Reprinted with permission from NFPA 72, National Fire Alarm Code®, copyright © 1996, National Fire Protection Association, Quincy, MA 02269. This reprinted material is not the referenced subject which is represented only by the standard in its entirety. Tables 19.1.7, 19.1.8, 19.1.9 and excerpts of text on pp. 19.2–29.7 Tables 1.8.2–1.8.6, 6.1.5, and 12.1.1 are reprinted with permission from 1996 Means Electrical Cost Data, copyright R.S. Means Co., Inc., Kingston, MA, 781-585-7880, all rights reserved. ACME Electric, Caterpillar, Cooper Bussmann, Cooper Crouse-Hinds, Cutler- Hammer, Ferraz Shawmut, General Cable Corporation, OSRAM Sylvania, and Siemens Corporation. Hickey_ FM 11/19/01 12:11 PM Page xxviii Acknowledgments Many thanks to the entire electrical staff at vanZelm, Heywood, & Shadford, Inc., for their valuable input, and to Kristine M. Buccino for her assistance in getting permission to reprint copyrighted material. A special thanks to Larry Hager and Steve Melvin and their team at McGraw-Hill, whose wonderful collaborative spirit and many professional talents transformed the raw manuscript into a published reality. And finally, a very special thanks to Chuck Durang of the National Fire Protection Association, whose invaluable cooperation and assistance made it pos- sible to incorporate the new 2002 NEC® edition changes in time for printing of this book. Hickey_ FM 11/19/01 12:11 PM Page xxix Contents Introduction Acknowledgments Section 1 General Information 1.1 1.1.0 Introduction 1.1 1.1.1 Project to do checklist (electrical) 1.2 1.1.2 Drawing design checklist (electrical) 1.5 1.1.3 Site design checklist (electrical) 1.8 1.1.4 Existing condition service and distribution checklist 1.10 1.1.5 Design coordination checklist (electrical) 1.13 1.1.6 Fire alarm system checklist 1.16 1.2.0 Electrical symbols 1.20 1.3.0 Mounting heights for electrical devices 1.31 1.4.0 NEMA configuration chart for general-purpose nonlocking plugs and receptacles 1.34 1.4.1 NEMA configuration chart for specific-purpose locking plugs and receptacles 1.35 1.5.0 IEEE standard protective device numbers 1.36 1.6.0 Comparison of specific applications of NEMA standard enclosures for indoor nonhazardous locations 1.42 1.6.1 Comparison of specific applications of NEMA standard enclosures for outdoor nonhazardous locations 1.42 1.6.2 Comparison of specific applications of NEMA standard enclosures for indoor hazardous locations 1.42 1.6.3 Knockout dimensions for NEMA standard enclosures 1.43 1.7.0 Formulas and terms 1.44 1.8.0 Introduction: typical equipment sizes, weights, and ratings 1.45 1.8.1 Typical equipment sizes: 600-V class 1.45 1.8.2 Transformer weight (lb) by kVA 1.46 1.8.3 Generator Weight (lb) by kW 1.46 1.8.4 Weight (lb/lf) of four-pole aluminum and copper bus duct by ampere rating 1.47 1.8.5 Conduit weight comparisons (lb per 100 ft) empty 1.47 1.8.6 Conduit weight comparisons (lb per 100 ft) with maximum cable fill 1.47 1.9.0 Seismic requirements 1.48 v Hickey_ FM 11/19/01 12:11 PM Page v iv vi Section 2 Requirements for electrical installations 2.1 2.1.1 Description of fuse class designations 2.2 2.1.2 Maximum peak let-through current (I p -amperes) and clearing I 2 t (ampere-squared-seconds) 2.3 2.2.1 Working spaces 2.4 2.2.2 Examples of conditions 1, 2, and 3 (working spaces) 2.5 2.2.3 Example of exception 1 (working spaces) 2.6 2.2.4 Example of exception 3 (working spaces) 2.6 2.2.5 Required 30-in-wide front working space (working spaces) 2.7 2.2.6 Required full 90-degree opening of equipment doors (working spaces) 2.7 2.3.1 NEC Section 110.26(C), basic rule, first paragraph (access to working space) 2.8 2.3.2 NEC Section 110.26(C), basic rule, second paragraph (access to working space) 2.8 2.3.3 Example of an unacceptable arrangement of a large switchboard (access to working space) 2.9 2.3.4 Example of exception no. 1 (access to working space) 2.9 2.3.5 Example of exception no. 2 (access to working space) 2.10 2.4.1 Working space and dedicated electrical space 2.10 2.4.2 Working space in front of a panelboard as required by NEC Section 110.26 2.11 2.4.3 Dedicated electrical space over and under a panelboard 2.11 2.5.1 Minimum depth of clear working space at electrical equipment 2.12 2.5.2 Elevation of unguarded live parts above working space 2.12 Section 3 Overcurrent protection 3.1 3.1.0 Introduction 3.3 3.1.1 NEC Section 90.2 Scope of the NEC 3.3 3.2.1 NEC Section 110.3(A)(5), (6) and (8) Requirements for equipment selection 3.3 3.2.2 NEC Section 110.3(B) Requirements for proper installation of listed and labeled equipment 3.4 3.2.3 NEC Section 110.9 Requirements for proper interrupting rating of overcurrent protective devices 3.6 3.2.4 NEC Section 110.10 Proper protection of system components from short-circuits 3.13 3.2.5 NEC Section 110.22 Proper marking and identification of disconnecting means 3.16 3.3.1 NEC Section 210.20(A) Ratings of overcurrent devices on branch circuits serving continuous and noncontinuous loads 3.16 3.4.1 NEC Section 215.10 Requirements for ground-fault protection of equipment on feeders 3.16 3.5.1 NEC Section 230.82 Equipment allowed to be connected on the line side of the service disconnect 3.17 3.5.2 NEC Section 230.95 Ground-fault protection for services 3.17 3.6.1 NEC Section 240.1 Scope of Article 240 on overcurrent protection 3.18 3.6.2 NEC Section 240.3 Protection of conductors other than flexible cords and fixture wires 3.19 vi Contents Hickey_ FM 11/19/01 12:11 PM Page vi 3.6.3 NEC Section 240.4 Proper protection of fixture wires and flexible cords 3.20 3.6.4 NEC Section 240.6 Standard ampere ratings 3.21 3.6.5 NEC Sections 240.8 and 380.17 Protective devices used in parallel 3.21 3.6.6 NEC Section 240.9 Thermal devices 3.21 3.6.7 NEC Section 240.10 Requirements for supplementary overcurrent protection 3.22 3.6.8 NEC Section 240.11 Definition of current-limiting overcurrent protective devices 3.23 3.6.9 NEC Section 240.12 System coordination or selectivity 3.24 3.6.10 NEC Section 240.13 Ground-fault protection of equipment on buildings or remote structures 3.25 3.6.11 NEC Section 240.21 Location requirements for overcurrent devices and tap conductors 3.25 3.6.12 NEC Section 240.40 Disconnecting means for fuses 3.27 3.6.13 NEC Section 240.50 Plug fuses, fuseholders, and adapters 3.28 3.6.14 NEC Section 240.51 Edison-base fuses 3.28 3.6.15 NEC Section 240.53 Type S fuses 3.28 3.6.16 NEC Section 240.54 Type S fuses, adapters, and fuseholders 3.29 3.6.17 NEC Section 240.60 Cartridge fuses and fuseholders 3.29 3.6.18 NEC Section 240.61 Classification of fuses and fuseholders 3.29 3.6.19 NEC Section 240.86 Series ratings 3.30 3.6.20 NEC Sections 240.90 and 240.91 Supervised industrial installations 3.30 3.6.21 NEC Section 240.92(B) Transformer secondary conductors of separately derived systems (supervised industrial installations only) 3.31 3.6.22 NEC Section 240.92(B)(1) Short-circuit and ground-fault protection (supervised industrial installations only) 3.31 3.6.23 NEC Section 240.92(B)(2) Overload protection (supervised industrial installations only) 3.31 3.6.24 NEC Section 240.92(C) Outside feeder taps (supervised industrial installations only) 3.31 3.6.25 NEC Section 240.100 Feeder and branch-circuit protection over 600 V nominal 3.32 3.6.26 NEC Section 240.100(C) Conductor protection 3.32 3.7.1 NEC Section 250.2(D) Performance of fault-current path 3.32 3.7.2 NEC Section 250.90 Bonding requirements and short-circuit current rating 3.32 3.7.3 NEC Section 250.96(A) Bonding other enclosures and short-circuit current requirements 3.32 3.7.4 NEC Section 250.122 Sizing of equipment grounding conductors 3.33 3.8.1 NEC Section 310.10 Temperature limitation of conductors 3.34 3.9.1 NEC Section 364.11 Protection at a busway reduction 3.34 3.10.1 NEC Section 384.16 Panelboard overcurrent protection 3.34 3.11.1 NEC Section 430.1 Scope of motor article 3.35 3.11.2 NEC Section 430.6 Ampacity of conductors for motor branch circuits and feeders 3.35 3.11.3 NEC Section 430.8 Marking on controllers 3.35 3.11.4 NEC Section 430.32 Motor overload protection 3.36 Contents vii Hickey_ FM 11/19/01 12:11 PM Page vii 3.11.5 NEC Section 430.36 Fuses used to provide overload and single-phasing protection 3.36 3.11.6 NEC Section 430.52 Sizing of various overcurrent devices for motor branch-circuit protection 3.37 3.11.7 NEC Section 430.53 Connecting several motors or loads on one branch circuit 3.38 3.11.8 NEC Section 430.71 Motor control-circuit protection 3.38 3.11.9 NEC Section 430.72(A) Motor control-circuit overcurrent protection 3.39 3.11.10 NEC Section 430.72(B) Motor control-circuit conductor protection 3.39 3.11.11 NEC Section 430.72(C) Motor control-circuit transformer protection 3.41 3.11.12 NEC Section 430.94 Motor control-center protection 3.42 3.11.13 NEC Section 430.109(A)(6) Manual motor controller as a motor disconnect 3.42 3.12.1 NEC Section 440.5 Marking requirements on HVAC controllers 3.42 3.12.2 NEC Section 440.22 Application and selection of the branch- circuit protection for HVAC equipment 3.43 3.13.1 NEC Section 450.3 Protection requirements for transformers 3.43 3.13.2 NEC Section 450.3(A) Protection requirements for transformers over 600 V 3.45 3.13.3 NEC Section 450.3(B) Protection requirements for transformers 600 V or less 3.45 3.13.4 NEC Section 450.6(A)(3) Tie-circuit protection 3.45 3.14.1 NEC Section 455.7 Overcurrent protection requirements for phase converters 3.46 3.15.1 NEC Section 460.8(B) Overcurrent protection of capacitors 3.46 3.16.1 NEC Section 501.6(B) Fuses for Class 1, Division 2 locations 3.46 3.17.1 NEC Section 517.17 Requirements for ground-fault protection and coordination in health care facilities 3.47 3.18.1 NEC Section 520.53(F)(2) Protection of portable switchboards on stage 3.47 3.19.1 NEC Section 550.6(B) Overcurrent protection requirements for mobile homes and parks 3.48 3.20.1 NEC Section 610.14(C) Conductor sizes and protection for cranes and hoists 3.48 3.21.1 NEC Section 620.62 Selective coordination of overcurrent protective devices for elevators 3.48 3.22.1 NEC Section 670.3 Industrial machinery 3.49 3.23.1 NEC Section 700.5 Emergency systems: their capacity and rating 3.50 3.23.2 NEC Section 700.16 Emergency illumination 3.50 3.23.3 NEC Section 700.25 Emergency system overcurrent protection requirements (FPN) 3.51 3.24.1 NEC Section 705.16 Interconnected electric power production sources: interrupting and short-circuit current rating 3.51 3.25.1 NEC Section 725.23 Overcurrent protection for Class 1 circuits 3.52 3.26.1 NEC Section 760.23 Requirements for non-power-limited fire alarm signaling circuits 3.52 viii Contents Hickey_ FM 11/19/01 12:11 PM Page viii [...]... 11/15/01 10:05 AM Page 1.1 Section 1 General Information 1.1.0 Introduction 1.1.1 Project To-Do Checklist (Electrical) 1.1.2 Drawing Design Checklist (Electrical) 1.1.3 Site Design Checklist (Electrical) 1.1.4 Existing Condition Service and Distribution Checklist 1.1.5 Design Coordination Checklist (Electrical) 1.1.6 Fire Alarm System Checklist 1.2.0 Electrical Symbols 1.3.0 Mounting Heights for Electrical... section provides information of a general nature that is needed frequently by electrical design and construction professionals Information that follows in subsequent sections is more specific in its applications 1.1 CH01_Hickey 1.2 11/15/01 10:05 AM Page 1.2 Section One 1.1.1 Project To-Do Checklist (Electrical) 1.1.1 (continued) CH01_Hickey 11/15/01 10:05 AM Page 1.3 General Information 1.1.1 (continued)... 11/15/01 10:05 AM Page 1.5 General Information 1.1.2 Drawing Design Checklist (Electrical) 1.1.2 (continued) 1.5 CH01_Hickey 1.6 11/15/01 10:05 AM Page 1.6 Section One 1.1.2 (continued) CH01_Hickey 11/15/01 10:05 AM Page 1.7 General Information 1.1.2 1.7 CH01_Hickey 1.8 11/15/01 10:05 AM Page 1.8 Section One 1.1.3 Site Design Checklist (Electrical) 1.1.3 (continued) CH01_Hickey 11/15/01 10:05 AM Page 1.9 General... illustration of Section 332.24, for bends in type MI cable 4.6.2 600-V MI power cable: size and ampacities 4.6.3 300-V MI twisted-pair and shielded twisted-pair cable sizes 4.6.4 MI cable versus conventional construction in hazardous (classified) locations 4.6.5 Engineering data: calculating voltage drop and feeder sizing (MI cable) 4.7.1 NEC Table 344.24, radius of conduit bends for IMC, RMC, RNC, and EMT... 11.9 11.9 11.9 11.9 11.9 11.9 11.9 11.21 11.21 11.21 11.21 11.21 11.21 11.21 11.21 11.21 11.21 11.21 Hickey_ FM 11/19/01 12:11 PM Page xvii Contents 11.1.36 Voltage-drop curves for typical interleaved construction of copper busway at rated load, assuming 70°C (158°F) as the operating temperature 11.1.37 Voltage-drop values for three-phase busways with copper bus bars, in volts per 100 ft, line-to-line... Section 20 Metrification 20.0.0 20.1.0 20.2.0 20.3.0 20.4.0 20.5.0 20.6.0 Introduction to the 1975 metric conversion act What will change and what will remain the same How metric units will apply in the construction industry Metrification of pipe sizes Metrification of standard lumber sizes Metric rebar conversions Metric conversion of ASTM diameter and wall-thickness designations 20.7.0 Metric conversion