OSHA Electric Power Standards – Simplified
Overhead Lines
Unique fall and electric shock hazards can occur during the installation and removal of lines and during tower and structure work. OSHA 29 CFR 1910.269(q) and 29 CFR 1926.964, both titled “Overhead lines and live-line barehand work,” address these hazards as well as the required controls for worker safety.
Note: Live-line barehand work, also found within the standard, is not addressed in this article.
Pole and Tower Failures
Pole and tower failures can easily occur due to additional or unbalanced stresses created during climbing and the installation or removal of equipment. Workers are required to check for structure safety and stability before work begins. Critical injuries and deaths have occurred when workers have been located on poles or towers that broke or collapsed.
If a pole or structure cannot withstand the imposed loads, it must be braced or reinforced to prevent failure before work begins. A pole must withstand the weight of a worker (a vertical force) and the forces resulting from the release and replacement of the overhead line (a vertical and possibly a horizontal force) when work involves removing and reinstalling an existing line on a utility pole. The additional stresses may cause the pole to break, particularly if it is rotten at its base. OSHA refers employers to Appendix D to 1910.269 and 1926 Subpart V, “Methods of Inspecting and Testing Wood Poles,” for ways to check the condition of a wood pole to determine the presence of decay or other conditions adversely affecting its strength.
Setting, Moving or Removing Poles
Ground workers have exposures to electric shock when setting, moving or removing poles near exposed energized overhead conductors. OSHA has identified electrocutions that have occurred when ground workers who were not wearing PPE were guiding poles into holes when a power line was contacted. To prevent these exposures, workers must wear electrical protective equipment or use insulating devices when handling a pole. It is important to remember workers cannot contact a pole being set, moved or removed near exposed energized overhead conductors with any uninsulated body part, so employers must ensure the methods used prevent contact.
Additionally, workers must be protected from pole holes, including during the installation and removal of poles. Pole holes must be physically guarded or attended to protect workers from falling into them. What does OSHA mean by the word “guarded”? It is important to utilize definitions found within the OSHA electric power standards to better understand the application of the standard. OSHA’s definition of “guarded” is as follows: “Covered, fenced, enclosed, or otherwise protected, by means of suitable covers or casings, barrier rails or screens, mats, or platforms, designed to minimize the possibility, under normal conditions, of dangerous approach or inadvertent contact by persons or objects.”
Installing and Removing Overhead Lines
This section of the standard addresses a multitude of requirements when overhead lines are installed or removed near exposed energized overhead conductors. When installing lines parallel to existing energized lines, employers must determine the approximate voltage to be induced in the new lines or ensure work is performed with the assumption that the induced voltage is hazardous. Additionally, the automatic reclosing feature on a protective device must be rendered inoperable when conductors being installed or removed cross over energized conductors greater than 600 volts.
The OSHA standard also requires workers to utilize a method that can prevent contact of energized parts when installing or removing overhead lines. Methods include the tension stringing method, or barriers or other equivalent methods that will prevent contact of energized parts.
The tension stringing method keeps the conductor being installed under tension to prevent it from contacting the existing energized electrical circuits, which may cross over or under or be parallel to the conductor being installed. The standard addresses areas related to the safe operation of reel-handling equipment, load ratings of stringing and pulling lines, conductor grips, load-bearing hardware, other rigging equipment and reliable communications.
Barriers, if used as a method, include rope nets and guards, which physically prevent one line from contacting another. Refer to the OSHA definition of “barrier,” which is a “physical obstruction that prevents contact with energized lines or equipment or prevents unauthorized access to a work area.”
Hazardous Differences in Electrical Potential
Workers operating equipment, performing ground duties or completing other tasks on or near energized lines and equipment during stringing operations can experience hazardous step and touch potentials should the equipment contact the energized lines. Fatalities have occurred due to ground workers walking near stringing equipment at the time of energization. OSHA requires employers to protect workers from hazards that might arise from equipment energization. Employers must be able to demonstrate that the methods in use protect each worker from the hazards that might arise if the equipment contacts an energized line. If they can’t, the measures used shall include all the following techniques:
- Using the best available ground to minimize the time the line remains energized.
- Bonding equipment together to minimize potential differences.
- Providing ground mats to extend areas of equipotential.
- Employing insulating protective equipment or barricades to guard against any remaining hazardous potential differences.
Towers and Structures
Workers cannot be positioned under a tower or structure while work is in progress unless the employer can demonstrate that the working position is necessary to assist employees working above. Additional requirements include tag lines or other similar devices used during construction to maintain control of tower sections while being raised or positioned.
Summary
It is extremely important to have a good understanding of hazardous differences of electrical potential when work is performed on or near overhead power lines. Too many electric power fatalities occur due to a poor understanding of the step and touch hazards that can be present during overhead power-line installation and removal. OSHA offers an excellent resource in Appendix C to 1910.269 and 1926 Subpart V, “Protection from Hazardous Differences in Electric Potential.” If you have not read this appendix, it provides a great overview of the hazards and mitigation required to protect workers.
About the Authors: Pam Tompkins, CUSP, CSP, is president and CEO of SET Solutions LLC. She is a 40-year veteran of the electric utility industry, a founding member of the Utility Safety & Ops Leadership Network and past chair of the USOLN executive board. Tompkins worked in the utility industry for over 20 years and has provided electric power safety consulting for the last 20-plus years. An OSHA-authorized instructor, she has supported utilities, contractors and other organizations operating electric power systems in designing and maintaining safety improvement methods and strategies for organizational excellence.
Matt Edmonds, CUSP, CIT, CHST, is vice president of SET Solutions LLC. A published author with over 15 years of safety management experience, he also is an OSHA-authorized instructor for general industry and construction standards. Edmonds provides specialty safety management services for electric power organizations throughout the U.S. He has been instrumental in the development of training courses designed for electric power organizations, including OSHA 10- and 30-hour courses and SET Solutions’ popular OSHA Electric Power Standards Simplified series.
About OSHA Electric Power Standards – Simplified: Topics in this series are derived from SET Solutions’ popular OSHA electric power course offered through the Incident Prevention Institute (https://ip-institute.com). The course is designed to help learners identify standard requirements and to offer practical ways to apply the standards.
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