Many power quality variations that occur within customer facilities are related to wiring and grounding problems. It is commonly stated at power quality conferences and in journals that 80 percent of all the power quality problems reported by customers are related to wiring and grounding problems within a facility. While this may be an exaggeration, many power quality problems are solved by simply tightening a loose connection or replacing a corroded conductor. Therefore, an evaluation of wiring and grounding practices is a necessary first step when evaluating power quality problems in general.

The National Electrical Code ( NEC ) ^[*] and other important standards provide the minimum standards for wiring and grounding. It is often necessary to go beyond Wiring and Groundingthe requirements of these standards to achieve a system that also minimizes the impact of power quality variations (harmonics, transients, noise) on connected equipment. While the intent of this book is to concentrate on subjects that are more amenable to engineering analysis, the basic principles of wiring and grounding are presented in this chapter to provide the reader with at least a fundamental understanding of why things are done. References are provided throughout the text for readers interested in further details.