P35.010: Live Working: Research, Techniques and Procedures

Update The Live Working Reference Guide (The Tan Book): The Tan Book is a comprehensive technical resource on live working and includes fundamentals and principles related to live working tools, equipment, methods, and training resources. The guide is designed to be used by utility personnel engaged in any aspect of live work, from transmission maintenance managers and supervisors to line workers. An updated version of the guide is published each year including new or reviewed content based on input from project members.

Evaluate Live Working Rope: Dielectric ropes are used in live work along with rigid insulating tools. EPRI has initiated evaluations of the electrical and mechanical performance of multiple makes and models of dielectric ropes. These tests include existing standard methods as well as simulated “real-world” conditions. In 2026, EPRI intends to perform additional exploratory testing and issue a technical guide on inspection and retirement of ropes intended for energized work.

Evaluate Portable Hot Stick Testing Devices: Hot stick handheld field testers are used to determine if fiber-reinforced plastic (FRP) sticks are electrically safe for contact with energized lines prior to work. Many utilities have questioned the detection effectiveness of such devices. This task intends to identify the commercially available testers and conduct tests to evaluate their performance. In 2026, laboratory testing results of some of these devices (e.g., Hubbell Wet/Dry Hotstick Tester, Hastings Hot Stick Tester, PENTA TTr2) are intended to be presented in a report.

Update the Minimum Approach Distance Calculator: This desktop software tool calculates and illustrates the minimum approach distance (MAD) for phase-to-ground and phase-to-phase clearances based on IEEE 516 and IEC 61472 formulae for utility-specific structures using line components and dimensions for that specific structure’s location. In 2026, EPRI plans to update the software with new features and bug fixes, and to start the development of a new structure model builder. This new structure module is to be designed to enable the creation of custom structures, incorporating features such as underbuilt conductors, braced post configurations, and asymmetric crossarms.

Perform Testing to Understand Insulating Tool Flashovers at Normal AC Voltages: Past industry insulating tool flashovers at normal ac system voltages have led EPRI to initiate a multi-year investigation to determine the root cause of the flashovers. Laboratory tests have been developed and performed based on hypotheses and/or numerical models to understand these occurrences. This research is part of a broader research effort that intends to investigate degradation and failure modes of insulating tools, research new materials to enhance tool performance, develop/search for new tool testing and inspection technologies, and develop reference and training materials that enhance worker safety in the use, inspection, testing, and care of insulating tools used in live work. In 2026, EPRI intends to conduct full-scale electrical testing of the hot stick flashover case studied through finite-difference time-domain (FDTD) analysis previously developed. Additionally, EPRI intends to issue a test report. These small and full-scale test results are planned to be published in the EPRI report, Understanding Insulating Tool Flashovers at Normal AC Voltages.

Evaluate Conductive Suits: This task aims to update and expand the investigation of conductive suits performed previously. It seeks to verify electrical performance of conductive suits available on the market, including shielding efficiency, current carrying capacity, and electric resistance degradation due to washing cycles. In 2026, EPRI intend to include the investigation of conductive suits intended for ac induction.

Evaluate Effects of High Temperature on Insulating Tools: This multi-year task seeks to identify mechanical and electrical effects on insulating tools, such as hot sticks and ropes, caused by contact exposure with conductors operating at high temperatures. This task is important as utilities have replaced conventional aluminum conductor steel-reinforced (ACSR) for high-temperature, low-sag (HTLS) conductors in order to increase the transmission capacity through higher temperature operation (up to 250°C).

Evaluate Performance of Insulating Tools in Realistic Environments: This task intends to perform electrical testing of lightly contaminated FRP sticks exposed to realistic scenarios, such as high humidity and light fog, in vertical and horizontal positions.

Host an Overhead Transmission Line (OHTL) Temporary Protective Grounding and Bonding Workshop: EPRI intends to host a two-day workshop on temporary protective grounding and bonding practices including laboratory demonstrations at its high-voltage laboratory facility in Lenox, Massachusetts.

Provide Tools and Resources on the Transmission Resource Center: The following calculators, tools, result summaries, and references are planned to be available on the Live Working Transmission Resource Center: