Personal Protective Grounding for Electric Power Facilities and Power Lines

Bijan Ghayour, P.E.

Course Outline

This 8-hour course provides electrical workers and facility managers with clear and consistent instructions and procedures for temporary grounding of deenergized and isolated high-voltage equipment (over 600 volts) for the purpose of bare hand contact.

Temporary grounding of deenergized and isolated high-voltage equipment is necessary to ensure that electrical workers are protected from hazardous electrical shock while working on deenergized equipment or power lines. The deenergized equipment or power lines could become accidentally energized by improper switching operations, stored energy in capacitors or rotating equipment, static build-up, faulted equipment, electromagnetic coupling, or lightning strikes.

Any employee working on de-energized high-voltage equipment should be thoroughly familiar with protective grounding requirements and procedures.

This course has been developed from industry standards, the evaluation of the existing facilities, and from surveys of the many existing power generation, transmission, and distribution facilities. This course offers practical guidelines in understanding the qualitative effects of electrical current on the human body, the basic criteria for safe grounding practices, implementation of the criteria, and examples for derivation of safe exposure voltage for shock survival, protective ground cable sizing, and power plant grounding worker exposure voltage calculations.

The course materials are based entirely on the Unified States Department of the Interior, Facilities Instructions, Standards, and Techniques Volume 5-1.

This course includes a multiple-choice quiz at the end, which is designed to enhance the understanding of course materials.

Learning Objective

The purpose of this course is to provide the electrical workers and facility managers with clear and consistent instructions and procedures for temporary grounding of deenergized and isolated high-voltage equipment (over 600 volts) for the purpose of bare hand contact.

At the conclusion of the course the student will be familiar with the:

• Basic criteria for safe grounding practices;
• Electric shock hazard analysis;
• Protective grounding requirements;
• Ground cable assemblies;
• Grounding cable;
• Cable ampacity;
• Grounding cable jackets;
• Grounding clamps;
• Ground cable ferrules;
• Application of protective ground cables;
• Determination of the maximum available fault current at worksite;
• Cable size and length;
• Inspection of ground cable assemblies;
• Confirmation of de-energized status;
• Hot stick;
• Hot horn or noisy tester;
• Neon-type indicator;
• Direct-reading voltmeter;
• Clean connections;
• Grounding cable installation;
• Multiphase, worksite grounding;
• Parallel grounds;
• Arc flash hazard analysis;
• Power and pumping plant protective grounding;
  o Three-phase tee grounding
  o Double-isolation grounding
  
• Switchyard and substation protective grounding;
  o General considerations for placement of protective grounds
  o Power circuit breakers and transformers
  o Disconnect switches and bus
  o Insulated high-voltage cable
  o Cable terminations
  o Midsection and splices
  o Cable testing
  o Grounding transformers and phase reactors
  o Capacitor banks
  o Mobile equipment
  
• Power line protective grounding;
  o Grounding on metal transmission structures
  o Lattice steel structure
  o Overhead ground wire
  o Structure footing ground
  
• Grounding on wood pole transmission structures;
• Transmission line terminal ground switches;
• Grounding on distribution lines;
• Surface equipment and vehicle grounding;
• Grounding on wood pole transmission structure;
• Care, inspection, and testing of protective grounding equipment;
• Qualitative effects of electric current on the human body;
• Derivation of safe exposure voltage for shock survival;
• Protective ground cable sizing examples;
• Power plant grounding worker exposure voltage calculation examples;
• Double-isolation grounding for generators connected to a common step-Up power transformer; and
• Technical considerations in protective grounding on transmission lines, substations, and switchyards.
  

Intended Audience

This course is intended for electrical engineers and maintenance personnel involved in the design, service and maintenance of power generation, transmission, and distribution facilities, pumping stations, switchyard and substations, and safety engineers involved with training of electrical workers and linemen for work on
high-voltage equipment.

Benefit to Attendees

The student will become familiar with the general guidelines and techniques of personal protective grounding for electric power facilities and power lines. The students will learn the basic criteria for safe grounding practices, electric shock hazard analysis, protective grounding requirements, determining the maximum available fault current at worksite, grounding cable size, length, and ampacity calculations, and proposed methods of installation and testing of personal protective systems in verity of power facilities, and power lines.

Course Introduction

Temporary grounding of deenergized and isolated high-voltage equipment is necessary to ensure that electrical workers are protected from hazardous electrical shock while working on deenergized equipment or power lines. The deenergized equipment or power lines could become accidentally energized by improper switching operations, stored energy in capacitors or rotating equipment, static build-up, faulted equipment, electromagnetic coupling, or lightning strikes.

Any employee working on de-energized high-voltage equipment should be thoroughly familiar with protective grounding requirements and procedures.

This course has been developed from industry standards, the evaluation of the existing facilities, and from surveys of the many existing power generation, transmission, and distribution facilities. The course offers practical guidelines in understanding the qualitative effects of electrical current on the human body, the basic criteria for safe grounding practices, implementation of the criteria, and examples for derivation of safe exposure voltage for shock survival, protective ground cable sizing, and power plant grounding worker exposure voltage calculations.

This course offers tables, calculation methods and examples for determining grounding cable ampacity, ampacity of parallel protective ground cables, and derivation of safe exposure voltage for shock survival, minimum approach distance for electrical workers, and equipment clearance distances for operation near exposed circuits in switchyard and substations.

This course also offers detailed study of touch, step, and mesh potentials including the methods for calculating these voltages, their effect on human body, and the methods of limiting them to safe and acceptable values. This is particularly important in the design of, and the maintenance operations in switchyard and substations.

Course Content

This course contains specific examples, with practical emphasis on the installation, inspection, and testing of personal protective grounding for power facilities and power lines.

You are required to study volume 5-1, Personal Protective Grounding for Electric Power Facilities and Power Lines, published by the Unites States Department of the Interior, Bureau of Reclamation.

Personal Protective Grounding for Electric Power Facilities and Power Lines (PDF 1.6MB)

(For an electronic copy of FIST 5-1 go to http://www.usbr.gov/power/data/fist_pub.html and then click on volume 5-1)

Please click on the above underlined hypertext to view, download or print the document for your study. Because of the large file size, we recommend that you first save the file to your computer by right clicking the mouse and choosing "Save Target As ...", and then open the file in Adobe Acrobat Reader. If you still experience any difficulty in downloading or opening this file, you may need to close some applications or reboot your computer to free up some memory.

The following contains the outline of volume 5-1, Personal Protective Grounding for Electric Power Facilities and Power Lines, published by the Unites States Department of the Interior, Bureau of Reclamation:

Personal Protective Grounding for Electric Power Facilities and Power Lines (PDF 1.6MB)

Table of Contents

1- Purpose and Scope
2- Definitions and Interpretations
3- Determine Need for Personal Protective Grounding
4- Basic Criteria for Safe Grounding Practices
5- Ground Cable Assemblies
6- Application of Protective Ground Cables
7- Power and Pumping Plant Protective Grounding
8- Switchyard and Substation Protective Grounding
9- Power Line Protective Grounding
References

Appendix A - Qualitative Effects of Electric Current on the Human Body
Appendix B - Derivation of Safe Exposure Voltage for Shock Survival
Appendix C - Example Protective Ground Cable Sizing
Appendix D - Example Power Plant Grounding Worker Exposure Voltage Calculation
Appendix E - Double-Isolation Grounding for Generators Connected toa Common Step-Up Power Transformer
Appendix F - Technical Considerations in Protective Grounding on Transmission Lines, Substations, and Switchyards
Appendix G - Protective Grounding Procedure Flow Chart

Quiz

Once you finish studying the above course content, you need to take a quiz to obtain the PDH credits.

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DISCLAIMER: The materials contained in the online course are not intended as a representation or warranty on the part of PDH Center or any other person/organization named herein. The materials are for general information only. They are not a substitute for competent professional advice. Application of this information to a specific project should be reviewed by a registered architect and/or professional engineer/surveyor. Anyone making use of the information set forth herein does so at their own risk and assumes any and all resulting liability arising therefrom.

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