Practical Grounding, Bonding, Shielding and Surge Protection

✍ Scribed by G Vijayaraghavan, Mark Brown, Malcolm Barnes CPEng BSc(ElecEng) MSEE

• Publisher: Butterworth-Heinemann
• Year: 2004
• Tongue: English
• Leaves: 247
• Series: Practical Professional Books
• Edition: 1
• Category: Library

✦ Synopsis

This book will allow you to gain practical skills and know-how in grounding, bonding, lightning & surge protection. Few topics generate as much controversy and argument as that of grounding and the associated topics of surge protection, shielding and lightning protection of electrical and electronic systems. Poor grounding practice can be the cause of continual and intermittent difficult-to-diagnose problems in a facility. This book looks at these issues from a fresh yet practical perspective and enables you to reduce expensive downtime on your plant and equipment to a minimum by correct application of these principles. Learning outcomes: * Apply the various methods of grounding electrical systems * Detail the applicable national Standards * Describe the purposes of grounding and bonding * List the types of systems that cannot be grounded * Describe what systems can be operated ungrounded * Correctly shield sensitive communications cables from noise and interference * Apply practical knowledge of surge and transient protection * Troubleshoot and fix grounding and surge problems * Design, install and test an effective grounding system for electronic equipment * Understand lightning and how to minimize its impact on your facility * Protect sensitive equipment from lightning · An engineer's guide to earthing, shielding, lightning and surge protection designed to deliver reliable equipment and communications systems that comply with international and national codes · Discover how to reduce plant downtime and intermittent faults by implementing best-practice grounding/earthing techniques · Learn the principles of cable shielding in communication networks

✦ Table of Contents

Cover......Page 1
Half Title Page......Page 0
Other titles in the series......Page 2
Title Page......Page 3
Copyright......Page 4
Contents......Page 5
Preface......Page 9
1.1 Introduction......Page 11
1.2 Basics of grounding......Page 12
1.4 Lightning and its effect on electrical systems......Page 14
1.5 Static charges and the need for bonding......Page 15
1.6 Ground electrodes and factors affecting their efficacy......Page 16
1.7 Noise in signaling circuits and protective measures such as shielding......Page 18
1.8 Surge protection of electronic equipment......Page 19
1.9 UPS systems and their role in power quality improvement......Page 20
1.12 Summary......Page 21
2.1 Introduction......Page 23
2.2 Ungrounded systems......Page 25
2.3 Solidly grounded systems......Page 26
2.5 Resonant grounding using neutral reactor......Page 28
2.6 Impedance grounding through neutral resistance......Page 29
2.7 Point of grounding......Page 30
2.8 Other challenges......Page 31
2.9 Summary......Page 33
3.2 Shock hazard......Page 34
3.3 Grounding of equipment......Page 37
3.4 Operation of protective devices......Page 38
3.5 Thermal capability......Page 39
3.7 Induced voltage problem......Page 40
3.9 Mitigation by reduction of conductor spacing......Page 41
3.11 Metal enclosures for grounding conductors......Page 42
3.13 Sensing of ground faults......Page 44
3.14 Equipotential bonding......Page 45
3.15 Summary......Page 47
4.1 Introduction......Page 48
4.2 Incidence of lightning......Page 51
4.3 Probability of lightning strike......Page 55
4.4 Method of lightning protection......Page 57
4.5 Planning for lightning protection......Page 60
4.6 Improvements to lightning protection......Page 61
4.7 Factors governing decision whether or not to protect......Page 62
4.8 Effect of lightning strike on electrical lines......Page 63
4.9 Summary......Page 64
5.2 What is static electricity?......Page 65
5.4 Some common examples of static buildup......Page 66
5.5 Energy of spark and its ignition capability......Page 67
5.7 Control of static electricity......Page 68
5.9 Summary......Page 71
6.2 Grounding electrodes......Page 72
6.3 Soil resistance......Page 73
6.4 Measurement of soil resistivity......Page 74
6.5 Resistance of a single rod electrode......Page 78
6.6 Current-carrying capacity of an electrode......Page 80
6.8 Measurement of ground resistance of an electrode......Page 81
6.9 Concrete-encased electrodes......Page 83
6.10 Corrosion problems in electrical grounding systems......Page 85
6.12 Chemical electrodes......Page 86
6.13 Summary......Page 88
7.2 What is a surge?......Page 89
7.3 Bonding of different ground systems as a means of surge proofing......Page 90
7.4 Surges and surge protection......Page 92
7.5 Principle of surge protection......Page 95
7.6 Surge protection of electronic equipment......Page 96
7.7 Achieving graded surge protection......Page 98
7.8 Positioning and selection of lightning/surge arrestor......Page 99
7.9 A practical view of surge protection for sensitive equipment......Page 102
7.10 Summary......Page 111
8.2 Definition of electrical noise and measures for noise reduction......Page 112
8.3 How are sensitive circuits affected by noise?......Page 115
8.4 Frequency analysis of noise......Page 116
8.5 Categories of noise......Page 119
8.6 Disturbances from other equipment in the same distribution system......Page 120
8.7 Earth loop as a cause of noise......Page 121
8.8 The ways in which noise can enter a signal cable and its control......Page 123
8.9 More about shielding......Page 127
8.10 Shielded isolation transformer......Page 131
8.11 Avoidance of earth loop......Page 133
8.12 Use of insulated ground (IG) receptacle......Page 135
8.13 Zero signal reference grid and signal transport ground plane......Page 136
8.14 Harmonics in electrical systems......Page 138
8.15 Summary......Page 141
9.2 Power quality issues......Page 142
9.3 Definitions of abnormal voltage conditions......Page 144
9.5 Regulating transformer......Page 147
9.6 Standby sources......Page 148
9.7 Electromechanical UPS systems......Page 152
9.8 Solid-state UPS systems......Page 154
9.9 Multiple units for redundancy......Page 156
9.10 Considerations in selection of UPS systems for ADP facilities......Page 157
9.12 UPS configurations and recommended grounding practices......Page 159
9.13 Summary......Page 163
10.2 Case study 1......Page 164
10.3 Case study 2......Page 165
10.4 Case study 3......Page 168
10.5 Case study 4......Page 169
10.7 Case study 6......Page 170
10.9 Case study 8......Page 172
A.1 USA – National Electrical Code (NEC) regulations relating to grounding practices......Page 175
A.2 South Africa – grounding practices as per SABS standards......Page 176
A.3 Ground electrode recommendations by different national codes......Page 181
A.4 Measurement of ground electrode resistance – recommended practice by South African standard SCSASAAL9......Page 185
B.1 Common neutral grounding practices in low-voltage consumer installations as per UK Code BS: 7671: 2000 (IEE wiring regulations)......Page 192
B.2 More on TN-C-S systems......Page 196
B.3 Installations where use of TN-C-S system is prohibited......Page 197
Appendix C: IEEE exposure classifications......Page 201
D.3 Alphabetical listing of terms used in this recommended practice......Page 203
D.4 Words avoided because of no single technical definition......Page 208
D.5 Abbreviations and acronyms......Page 209
D.6 References......Page 210
E.2 Ensuring proper grounding......Page 211
Problem 2......Page 217
Problem 7......Page 218
Problem 10......Page 219
Problem 1......Page 220
Problem 3......Page 222
Problem 4......Page 223
Problem 5......Page 224
Problem 7......Page 225
Problem 8......Page 226
Problem 10......Page 229
Case study 1......Page 231
Case study 2......Page 233
Case study 3......Page 234
Case study 4......Page 235
Case study 5......Page 237
Case study 6......Page 238
Case study 7......Page 240
Case study 8......Page 241
Index......Page 243