Cover image for Electrical grounding : bringing grounding back to earth
Electrical grounding : bringing grounding back to earth
O'Riley, Ronald P., 1914-
Personal Author:
Sixth edition.
Publication Information:
Albany, NY : Delmar Thomson Learning, [2002]

Physical Description:
xxiv, 305 pages : illustrations ; 28 cm
General Note:
"Based on the 2002 National Electric Code."

Includes index.

Format :


Call Number
Material Type
Home Location
Item Holds
TK3227 .O78 2002 Adult Non-Fiction Central Closed Stacks-Oversize
TK3227 .O78 2002 Adult Non-Fiction Non-Fiction Area-Oversize

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The sixth edition of Electrical Grounding has been thoroughly updated in accordance with the 2002 National Electrical Code (NEC®), including a major reorganization of sections in Chapter 3 of the NEC and increased use of metric measurements. Early chapters serve as an orientation to the "what" and "why" of grounding, including explanations of the electrical theory and terminology used in Article 250 of the NEC®. Subsequent chapters of the book permit readers to explore individual conductors used in the grounding system in detail, starting with the grounding electrode. Permitted materials (including metal, steel and encased concrete), installation, sizing, and potential pitfalls are addressed. Once readers have become comfortable with basic installations, the book devotes attention to special installations, such as: separately derived systems, multiple buildings or structures served by a common service, high-voltage installations, and the use of ground-fault protection. The author's unique systematic approach has served as an effective path to true understanding of every phase of electrical grounding for countless journeyman electricians.

Table of Contents

Prefacep. xi
List of NFPA Materialsp. xvii
Introductionp. xix
Chapter 1 Article 250, Groundingp. 1
Overview of Article 250, Groundingp. 3
Definitionsp. 6
Chapter 2 Electrical Theory Applicable to Groundingp. 14
Current Flowp. 14
The Electronp. 15
Ohm's Lawp. 16
Direct Currentp. 17
Series Circuitp. 17
Alternating Currentp. 19
Impedancep. 21
Amps and Overcurrent Protective Devicesp. 21
Parallel Circuitp. 22
Series-Parallel Circuitp. 23
Chapter 3 Grounding for Safetyp. 24
Electric Shockp. 24
Potential Differencep. 26
Grounding and Electric Shockp. 27
Chapter 4 Faultsp. 30
Types of Faultsp. 31
Stresses Caused by Faultsp. 32
Ionizationp. 32
Grounded-System Faultsp. 33
Impedance-Grounded Systemsp. 35
Ungrounded System Faultsp. 37
Ground Fault Detectorsp. 39
Chapter 5 Grounding Electrode Systemp. 40
Grounding Theoryp. 40
Responsibility of the Grounding Electrodep. 41
The Ground Rodp. 43
Grounding Electrode Systemp. 47
Metal Water Pipe Electrodesp. 48
Supplemental Electrodesp. 49
Building Steel as an Electrodep. 50
Concrete-Encased Electrodesp. 51
Ground Ring Electrodesp. 52
Rod and Pipe Electrodesp. 53
Plate Electrodesp. 53
Dwelling Unit Electrodep. 54
Summaryp. 59
Chapter 6 Grounding Electrode Conductorp. 61
Definition of Grounding Electrode Conductorp. 62
Materialsp. 63
Splicingp. 63
Installation and Protectionp. 64
Connecting the Grounding Electrode Conductorp. 68
Sizing the DC Grounding Electrode Conductorp. 71
Sizing the AC Grounding Electrode Conductorp. 72
Sizing Grounding Electrode Conductorsp. 74
Summaryp. 80
Chapter 7 Circuit and System Groundingp. 82
Why Ground Circuits and Systems?p. 83
Definitionsp. 83
Direct-Current Systemsp. 85
Alternating-Current Systemsp. 86
AC Systems Not Required to Be Groundedp. 91
High-Impedance Groundingp. 92
Chapter 8 Grounded Conductorp. 97
Definition of Grounded Conductorp. 97
Grounded Conductor Connection in a Direct-Current Systemp. 98
Grounded Conductor Connection in an Alternating-Current Systemp. 98
Bringing the Grounded Conductor to Servicep. 99
Sizing the Grounded Conductorp. 101
Installing the Grounded Conductorp. 105
System or Circuit Conductor to be Groundedp. 106
Identifying the Grounded Conductorp. 106
Grounded Conductor Overcurrent Protectionp. 108
Chapter 9 Main Bonding Jumperp. 110
Definition of Main Bonding Jumperp. 111
Location of the Main Bonding Jumperp. 112
Materials for the Main Bonding Jumperp. 112
Connectionsp. 114
Sizing the Main Bonding Jumperp. 114
Chapter 10 Equipment Grounding Conductorp. 122
Definition of Equipment Grounding Conductorp. 123
Definition of Systemp. 123
Definition of Circuitp. 125
Performance of Fault Current Pathp. 126
Types of Equipment Grounding Conductorsp. 127
Wire Used for Equipment Grounding Conductorp. 127
Identification of Equipment Grounding Conductorp. 128
Installation of Equipment Grounding Conductorp. 130
Raceways as Equipment Grounding Conductorsp. 133
Earth as an Equipment Grounding Conductorp. 142
Equipment Grounding Conductor Connectionsp. 142
Equipment Grounding Conductor Continuityp. 143
Sizing Equipment Grounding Conductorsp. 144
Equipment Grounding Conductor in Boxesp. 151
Agricultural Buildingsp. 154
Chapter 11 Equipment and Enclosure Bondingp. 156
Definitionsp. 157
Materialsp. 159
Connectionsp. 159
Bonding at Service Equipmentp. 159
Sizing Bonding Jumpers on Supply Side of Servicep. 165
Grounding Electrode Conductor Enclosure Bondingp. 173
Flexible Metal Conduit in Service-Entrance Racewayp. 174
Bonding Other Than at Servicep. 174
Structural Bonding Steelp. 176
Sizing Load Side of Service Bonding Jumpersp. 178
Bonding Grounding Electrode Systemsp. 180
Bonding Receptaclesp. 183
Bonding Lightning Protection Systemp. 183
Establishing an Equipotential Plane in an Agricultural Buildingp. 184
Swimming Pool Bonding Gridp. 184
Summaryp. 187
Chapter 12 Equipment and Enclosure Groundingp. 188
Why Ground Metal Enclosures and Equipment?p. 188
Enclosure and Raceway Groundingp. 189
Part VI. Equipment Groundingp. 191
Methods of Grounding Enclosures and Equipmentp. 197
Grounding Panelboardsp. 198
Isolated Equipment Grounding Receptaclesp. 200
Tower Groundingp. 204
Computer Groundingp. 204
Chapter 13 Grounded Circuit Conductor for Grounding Equipmentp. 209
The Basic Rulep. 210
Supply-Side Usep. 210
Second Buildingp. 211
Separately Derived Systemp. 211
Load-Side Usep. 212
Summaryp. 215
Chapter 14 Ground-Fault Protective Equipmentp. 216
Ground-Fault Protection of Equipmentp. 217
Ground-Fault Protection Equipment Required at Servicep. 218
Ground-Fault Protection Equipment Required--Feederp. 221
Definition of Ground-Fault Circuit Interrupterp. 221
Receptacles Requiring GFCI Protectionp. 223
Replacing Nongrounded Type Receptaclesp. 224
Arc Fault Circuit Interrupter (AFCI)p. 232
Chapter 15 System and Circuit Grounding 1 kV and Overp. 234
Neutral Grounded Systemsp. 235
Neutral Grounded Systems Required and Permittedp. 235
Solidly Grounded Systemsp. 237
Impedance-Grounded Systemsp. 238
Equipment Groundingp. 239
Chapter 16 Separately Derived Systemsp. 242
Definition of Separately Derived Systemp. 242
Bonding Jumperp. 245
Grounding Electrode Conductorp. 246
Grounding Electrodep. 247
The Grounding Electrode Conductorp. 247
Bonding at Separately Derived Systemsp. 250
Dedicated Five-Wire Systemp. 251
Portable Generatorsp. 251
Vehicle-Mounted Generatorsp. 251
Chapter 17 Two or More Buildings Supplied by One Servicep. 254
Disconnecting Meansp. 255
Grounded and Ungrounded Systemsp. 255
Second Building Grounding Electrode Systemp. 261
Sizing the Grounding Electrode Conductor at the Second Buildingp. 261
Sizing the Equipment Bonding Jumper at the Second Buildingp. 262
Disconnecting Means at the Second Buildingp. 262
No Disconnecting Means at the Second Buildingp. 263
Agricultural Buildingsp. 263
Chapter 18 Calculating Fault Currents and Grounding Conductor Withstand Ratingp. 269
Introductionp. 269
Purpose of Groundingp. 270
Short-Circuits and Ground Faultsp. 271
Protective-Device Termsp. 271
Important Code Requirementsp. 273
Fault-Current Pathp. 273
Available Fault Currentp. 273
Factors Affecting Amount of Fault-Currentp. 276
Transformer Secondary Currentp. 276
Transformer Impedancep. 277
Other Factors Affecting Fault-Current Valuesp. 278
Point-to-Point Calculationsp. 278
Fault-Current and Parallel Conductorsp. 281
Combining Fuse and Circuit Breaker for Protectionp. 282
Summaryp. 283
Appendixp. 287
Indexp. 295