iii The purpose of Modern Commercial Wiring is to help the electrical practitio- ner—student, apprentice, journeyman, designer, engineer, contractor, and maintenance person—working in the commercial electrical trade. This text- book is written in clear and simple language from one electrician to others. Basic electrical concepts and theory are reviewed, but this textbook as- sumes you have some prior knowledge and experience with electrical princi- ples and electrical wiring. Every chapter is geared toward providing you with design criteria, methods, and requirements of the National Electrical Code®*. A concentrated effort has been made to be accurate in order to provide useful instruction and guidance that can be implemented in the real, day-to-day practices of commercial wiring. This includes (but is not restricted to) install- ing, designing, troubleshooting, and maintaining electrical systems, devices, and equipment. The chapters are arranged in a logical sequence but are not dependent on one another. Each could be studied as a stand-alone entity. The chapters begin with clear objectives and close with review questions to reinforce what has been learned. Hopefully, this volume will provide many instructive and useful bits of information to the reader. Harvey N. Holzman Preface Harvey N. Holzman is a licensed Master Electrician with 45 years of hands-on experience in several states, including New York, Florida, Kansas, North Caro- lina, Pennsylvania, and Texas. Besides owning his own electrical contracting services company, Mr. Holzman has worked for several major constructors at both refi neries and power generating stations, providing consulting, supervi- sion, and fi eld engineering. He has been a member of many electrical trade or- ganizations and has trained dozens of individuals, many of whom have gone on to become master electricians. About the Author *NFPA 70®, National Electrical Code®, and NEC® are registered trademarks of the National Fire Protection Association, Quincy, MA.