iii The purpose of Modern Commercial Wiring is to help the electrical practi- g tioner—student, apprentice, journeyman, designer, engineer, contractor, and maintenance person—working in the commercial electrical trade. It is writ- ten in clear and simple language from one electrician to others. Basic electrical concepts and theory are reviewed, but it is assumed the reader has some prior knowledge and experience with electrical principles 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 give the reader 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) installing, 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. Your comments and suggestions for additions and improvements are most welcome and will serve to enhance future editions. Harvey N. Holzman Preface