IEEE 953

PREFACE

The subjects covered by this report are divided into four parts corresponding to the four chapters.

Chapter I covers the problems of system grounding; that is, connection of the neutral, the corner-of-the-delta or mid-tap of one phase to ground. This chapter discusses the pros and cons of grounded versus ungrounded systems. If it is decided to ground, information is given on how to ground the system, where the system should be grounded and how to select equipment for the grounding of the neutral circuits.

Chapter II deals with the problems of connecting the frames and enclosures of electric apparatus such as motors, switchgear, transformers, buses, cables, conduits, building frames, portable, equipment, etc., to a ground system. It also outlines the fundamentals of making the interconnection or ground conductor system between electric equipment’s and the ground rods, water pipes, etc.

Chapter III deals with the problems of static — how it is generated, what processes may produce static, how it is measured, and what should be done to prevent its generation or to drain the static charges to earth to prevent sparking. It also covers the methods of protecting structures against the effects of lightning. It is not a treatise on the application of lightning arresters but, because the system for protecting structures against lightning consists entirely of conductors to earth, it is considered within the scope of this report to discuss the general aspects of the problem.

Chapter IV deals with the problems of obtaining a low resistance connection to the earth. The use of ground rods, connections to water pipes, etc., are discussed.

Looking at the problem from an overall standpoint, the grounding of the system would in most cases be done by making a metallic connection direct or through impedance between transformer or generator neutrals and the building grounding system which is described in Chapter 11. The grounding system described in Chapter II in turn is connected to earth through the system of ground rods and water pipes descried in Chapter IV.

The protective systems discussed for static and lightning protection in Chapter III would likewise be connected to the ground rods and water pipe system as outlined in Chapter IV.