Title: Grounds for Grounding
Author: E.B. Joffe and K.S. Lock
Publisher: John Wiley, 2010
ISBN: 978-0-471-66008-8

The topic of “grounding” in Electromagnetic Compatibility (EMC) is one of the most controversial in this engineering discipline.
     The famous EMC saying, “Ground is a place for potatoes and carrots to grow,” [1] gives a taste of the easiness with which this concept can be (or, much better, it is) misunderstood by today’s engineers.
     On June 4, 1999 I attended a seminar given by the main author of the book, Elya Joffe, at the University of Rome “La Sapienza” on the topic of grounding principles. The rigorous logic with which the concepts were given and the explanation of their physical foundations left an important mark on my technical background. Reading this book, I’ve found again these important characteristics of the knowledge sharing.
     In this book of more than 1,000 pages, the authors demonstrate that grounding theory is not intuitive, but the design of any grounding system is founded on solid science. Achieving a functional grounding philosophy often results from battles of wits, perseverance – and the resolution of conflicts in between – intuition, engineering experience, and judgment.
     A key objective of this book is to dispel the mystery associated with grounding. This is accomplished in the 10 chapters by providing a methodical approach for the design of grounding systems, from circuits through systems and up to platforms and facilities. The book, in my opinion, meets the above challenge by putting grounding into the proper perspective. It outlines a physical foundation for explaining the concept of grounding, founded on electromagnetic field theory, while providing insight into practical aspects of grounding system implementation, particularly as related to its interdisciplinary nature, extending from circuits to facilities. It is clearly demonstrated that grounding systems in facilities, systems, or circuits do, in fact, follow a consistent scheme.
     The book begins in Chapter 1 by introducing the reader to the fundamental concepts pertaining to grounding, starting with a discussion of Maxwell’s equations, particularly as they apply to the topic of grounding. Essential terms and concepts relating to real-world electrical circuit behavior are reviewed in Chapter 2.
     Chapter 3 presents the basics of grounding, beginning with a discussion of the term “ground” and the different objectives of grounding.
     Chapter 4 is one of the chapters I like the most. In an excellent logical sequence it provides an in-depth review of the fundamentals of grounding design. The key issue emphasized in this chapter is that the term “ground” actually relates to the concept of current return path, a key notion throughout the book. Chapter 4 discusses in detail the fundamental topologies of grounding systems and provides a novel yet practical systematic approach for planning grounding systems. The concept of “ground loops” is developed and solutions are presented. The implementation of the fundamental grounding architectures in large-scale systems and installation are further examined. Chapter 4 ends with grounding-related case studies.
     Chapter 5 explains the principles of bonding. The approaches of achieving low-impedance connections between metallic surfaces and structures as a fundamental objective for meeting the desired grounding objectives are portrayed.
     Chapter 6 describes in detail safety-related grounding concerns. Rationale for electrical safety grounding requirements is provided and safety grounding design principles in power distribution and lightning protection systems are presented.
     Chapter 7 covers grounding in wiring and cable systems. One of the most controversial and misunderstood aspects of system grounding design stems from the question of cable shield termination (“grounding”). In this Chapter I’ve found, for the first time, a clear distinction between signal grounding and shield termination.
     Chapter 8 provides the foundation for understanding the essential necessity of adequate grounding of EMI terminal protection devices (e.g., EMI filters and transient-suppressing devices) performance. The effect of acceptable versus objectionable grounding of such protective devices is clearly demonstrated.
     In Chapter 9 (of some 250 pages) the application of grounding in printed circuit boards (PCBs) is discussed in depth, particularly as related to power conditioning and signal return paths. The question of grounding in mixed analog/digital circuits is also addressed. Novel and emerging techniques, associated with (AC) grounding structures, such as “high impedance surfaces” (HIS), also known as “electromagnetic band-gap” (EBG) are also introduced.
     Chapter 10 leads the reader to the facility and platform levels. The design of integrated grounding systems in facilities is described. The complexity of and approaches to the integration of multiple subsystems into a larger system as related to grounding system design are discussed. It also expands the concept of grounding architecture design to the unique cases of mobile platforms, for example, tactical C3I (command, control, communication, and intelligence) shelters, aircraft, space systems and ships.
     The several appendices in the book are one of the key points of this book. They provide extensive supporting information and supplemental data, which will be of great use for the reader. Appendix A provides a glossary of grounding-related terms and definitions, with references to their sources, particularly when derived from official international standards and codes. When several definitions exist for a term, they are all included, with reference to the context of their applicability. Appendix B lists commonly used acronyms employed throughout the book for easy reference by the reader. Appendix C presents commonly used symbols associated with variables referred to throughout the book. Appendix D presents a list of many grounding-related standards, specifications, and codes with their scope. Appendix E demonstrates the equivalence between Ohm’s Law and Fermat’s “Least Time” Principle, which is useful for understanding the reason why current selects a particular return path. Finally, Appendix F provides an overview of S-parameters and their application for the evaluation of grounding performance, particularly on printed circuit boards, extensively used in Chapter 9.
     I am certain that this book, founded on fundamental physical principles on the one hand and on real-world, practical experience on the other, provides an excellent resource for achieving successful, cost-effective, and timely state-of-the-art designs of electronic and electrical equipment, systems and networks. This book will not completely replace experience and experiment, but it will greatly shorten the path to a successful design.

[1] B. Archambeault, PCB Design for Real-World EMI Control, Kluwer Academic Publisher, 2002, USA.                                                            EMC