The Evolution of Personal Protective Grounding: Part 2

Part 1 of this article began with discussion of the first American power systems, when lineworkers initially encountered the hazards of working on de-energized lines (see https://incident-prevention.com/blog/the-evolution-of-personal-protective-grounding-part-1/). This led to early personal protective grounding (PPG) efforts using trial and error. We also reviewed Charles Dalziel’s contributions toward a greater industry understanding of dangerous current levels.

In short, Part 1 confirmed the need for PPG as a key lineworker safety precaution. In this second and final part, we will review PPG’s evolution as the industry designed and improved relevant equipment, conducted more testing and developed written standards.

1940-1970: Equipment Design and Improvements
In the 1940s, protective grounds were used sporadically depending on the utility company and the line crew foreman. It was a relatively common practice for lineworkers to make their own ground sets, using #6 soft-drawn copper and hot-line tap clamps. During this period, the industry began moving away from homemade grounding equipment in favor of equipment manufactured by companies including A.B. Chance, J.R. Kearney and Safety Live Line Co.

In the 1950s, A.B. Chance offered various PPG components. Around the same time, Safety Live Line Co. of Oakland, California, manufactured a grounding cluster that featured a removable twist-lock handle. It had been determined by this point that it is best to have the grounding conductors short-circuit the line and connect it to ground.

Further, using wood-handled sticks to install protective grounds had started to become standard. The grip-all or “shotgun stick” developed in the 1950s became popular for protective ground installation and removal. Some manufacturers made protective grounds with wood-handled sticks that were permanently attached to the grounding clamps. The sticks significantly improved safety, placing workers farther from conductors in case a hot line was grounded.

This era also saw an increased interest in testing. The “fuzzing” test procedure was included in the fourth edition of “The Lineman’s and Cableman’s Handbook,” published in 1964. The fourth edition also stated that after the test, two sets of grounds shall be placed on either side of the work area, within sight of the lineworkers.

The fifth edition of the handbook (1976) recommended using a voltage detector for testing, yet it also noted that fuzzing using “fuzz rings” could be effectively performed on higher voltages. These rings were not widely used and are now quite rare. A fuzz ring’s size and shape increased the sound level for lineworkers. It was also around this time when many power companies began providing documented rules and procedures regarding the application of personal protective grounds.

Bonneville Testing
In 1954, Bonneville Power Administration conducted comprehensive testing to evaluate the effectiveness of protective grounds in ensuring the safety of its lineworkers. The tests produced the following key findings:

• “The current practice utilized by most power companies of installing grounds on adjacent structures to the one being worked on will likely not provide adequate protection for the linemen in the event the line comes energized.”
• “The short-circuiting and grounding of all conductors at work locations, using jumpers and clamps of adequate current-carrying capacity, will likely provide sufficient protection for linemen.”

These results caused many power companies to reevaluate their protective grounding practices. Before the BPA testing, protective grounds were typically bracketed around the work location but not on the structure where the work was being done. The theory at the time was that grounds only needed to be placed between the worker and the energy source. From this point forward, the industry slowly evolved toward installing protective grounds at the work location. BPA also performed testing of personal protective grounds exposed to the high fault currents that were becoming more prevalent.

1970-1990: More Improvements
Considerable improvements were made to protective grounding equipment during this 20-year span, including equipment for use when stringing conductors and performing underground work. Manufacturers introduced equipment for testing components to ensure their capacity and reliability.

The sixth (1981) and seventh (1986) editions of “The Lineman’s and Cableman’s Handbook” listed the following requirements for effective protective grounding: a low-resistance path to earth; clean and tight connections; connections made to proper points; and adequate grounding equipment capacity.

The United States Congress enacted the Occupational Safety and Health Act in 1970, which established OSHA. Over time, OSHA issued various regulations related to protective grounding. Here’s what a couple of the first ones stated:

• “Protective grounds shall be applied on the disconnected lines or equipment to be worked on.”
• “Visual inspections or tests shall be conducted to ensure that equipment or lines have been deenergized.”

During this period, power companies gradually started moving toward worksite grounding, with “single-point grounding” and other terms surfacing. The following statement was published in the seventh edition of “The Lineman’s and Cableman’s Handbook”: “The protective grounds are installed from ground in a manner to short-circuit the conductors so that the lineman and everything in the work area will be at equal potential.” It had also been determined that by short-circuiting a line, any protective devices supplying the line would rapidly relay out if inadvertently energized.

The steady rise in fault currents was another factor affecting adequate protective grounding, increasing the need for well-made grounding components, such as clamps and cables. In 1983, ASTM F855, “Standard Specifications for Temporary Protective Grounds to Be Used on De-energized Electric Power Lines and Equipment,” was first published. The comprehensive standard covered the design, materials, ratings and design testing of clamps, ferrules, cables and ground assemblies. It was a key element in standardizing and improving the quality of grounding components.

1990-2020: Equipotential Concept
As power companies and equipment manufacturers conducted more testing, they eventually concluded that the only safe way to protect lineworkers with PPG was to place them in an equipotential zone. In 1994, OSHA issued the 1910.269 standard, which contained this text at (n)(3): “Temporary protective grounds shall be placed at such locations and arranged in such a manner as to prevent each employee from being exposed to hazardous differences in electric potential.” Companies then devised various grounding and bonding procedures to mitigate placing lineworkers between different potentials at the worksite. The industry was slow to change from conventional bracket grounding to worksite grounding as power companies felt compliance with the equipotential theory was unnecessary and would add considerable time to jobs.

Since 1994, the industry has generally accepted the use of bonding and grounding to prevent employees from being exposed to hazardous differences in electric potential.

ASTM F2249, “Standard Specification for In-Service Test Methods for Temporary Grounding Jumper Assemblies Used on De-Energized Electric Power Lines and Equipment,” was initially published in 2003. It provided guidelines for inspecting and testing protective grounds. Manufacturers including Hubbell Power Systems and Hastings developed ground component testers, line testers, simulators and other PPG improvements. Hubbell also issued its encyclopedia of grounding during this period, providing a comprehensive reference on the subject.

The IEEE 1048 standard published in 1990 provided the first comprehensive guide for protective grounding of power lines. Most recently updated in 2016, it remains an excellent source of PPG information.

This period also saw the development of several methods and types of equipment that would eliminate or minimize the potential differences lineworkers might encounter. These included significant improvements in grounding equipment and procedures for wire stringing.

Conclusion
We have come a long way from the days of pulling a chain attached to a water pipe over conductors. There is no question that the subject of PPG has become increasingly complex, with the industry’s experience and research evolving over the years. This complexity underscores the continued need for effective worker training and education. One condition, however, remains the same: PPG has always been a key element of safety for work on electric power systems. It is as important today as it was 100 years ago.

About the Author: Alan Drew began his power industry career in 1959. While working for a local utility company, he earned a bachelor’s degree in electrical engineering. Drew was hired as the general superintendent for Clallam County Public Utility District in 1991. He moved to Boise, Idaho, in 1998, where he became an instructor with Northwest Lineman College and advanced to the position of senior vice president of research and development. He is a lifetime member of IEEE and a 2008 International Lineman Museum Hall of Fame inductee. Drew’s most recent accomplishment is writing “The American Lineman,” a book that honors the evolution and importance of the U.S. lineman. He retired in 2020 and is now a part-time technical consultant for Northwest Lineman College.