Working around overhead power lines can be dangerous and even deadly to workers. Contact with power lines has been identified by the Occupational Safety and Health Administration (OSHA) as one of the most frequent causes of electrical injuries. Utility linemen risk falls, electric shocks, burns, and other injuries with some of these incidents causing fatalities. Other job categories where employees are at potential risk from working near overhead power lines include drill rig operators, crane operators, hoist operators, arborists, construction workers, and painters.
Every day, four construction workers die on the job in this country. The leading cause of construction worker deaths is from falls, but the second leading cause is from electrocution.
The primary cause of construction electrocutions is contact with overhead power lines. The Department of Labor's Bureau of Labor Statistics' data indicate that of the 279 workplace electrocutions in 1996, 116 were from contact with overhead power lines. OSHA data indicate that in 1998 and 1999, 277 workers died from contact with overhead power lines. The National Traumatic Occupational Fatalities (NTOF) database indicates that the average annual fatality rate for power line workers is 56.3 deaths per 100,000 employees.
Electrocutions occur when workers using cranes, metal ladders, scaffolds, conveyors, front-end loaders, dump trucks, or other equipment or materials contact an overhead power line. Most workers electrocuted by contacting overhead power lines are working with cranes, working on scaffolds, or using ladders. Too often, workers die during what appears to be an accident-proof activity such as unloading supplies from a truck, moving ladders from the side of a structure, adding the final touches to a roofing job—all while near power lines. Poor planning and a moment's inattention may lead to contact with high-voltage power lines and result in serious injury or death. Employers should determine whether overhead power lines near workers are live, determine the distances separating workers from the identified high-voltage lines, and whether the employees could encounter them when working on elevated equipment or structures.
In the United States (U.S.), OSHA addresses the health and safety of workers potentially working near overhead power lines under the General Industry scenario in 29 Code of Federal Regulation (CFR) Part 1910.269 “Electrical Power Generation, Transmission, and Distribution” , and under the Construction Industry scenario in 29 CFR Part 1926 Subpart V “Electric Power Transmission and Distribution” . Effective July 10, 2014, OSHA revised the construction standard for electric power line work to make it more consistent with the corresponding general industry standard so that the same rules apply generally to the same kinds of work. The compliance deadline for some provisions on fall protection, minimum approach distances, and arc-flash protection was April 1, 2015.
OSHA based its revisions on the latest consensus standards and improvements in electrical safety technology. The final rule includes new or revised requirements for fall protection, minimum approach distances, electrical protective equipment, and arc-flash protection, and for host employers and contract employers to exchange safety-related information. The reader is referred to these citations for detailed information addressed by the regulations, and for potential use in preparing a Job Hazard Assessment (JHA) or Job Safety Assessment (JSA). Nonetheless, some the significant changes to these regulations are summarized in the following sections.
- The degree of training must be determined by risk to the worker for the hazard involved.
- Qualified workers must have training to recognize and control or avoid electrical hazards present at the worksite.
- Line-clearance tree trimmers must have training to distinguish exposed live parts and to determine the voltage on those parts, and they must have training in minimum approach distances and how to maintain them.
- It is no longer necessary for employers to certify that workers are proficient in safe work practices.
Host Employers and Contractors
- Host and contract employers must share information with each other on safety-related matters and must coordinate their work rules and procedures.
- On and after April 1, 2015, qualified workers must use fall protection when climbing or changing location on poles, towers, or similar structures unless climbing or changing location with fall protection is infeasible or creates a greater hazard than climbing or changing location without it.
- Fall arrest equipment must be capable of passing a drop test after exposure to an electric arc with a heat energy of 40±5 calories per centimeter squared (cal/cm 2 ) if the workers using the fall protection are exposed to flames or electric arc hazards.
- On and after April 1, 2015, work-positioning equipment must be rigged so that workers can free fall no more than 0.6 meters (2 feet).
- Revised minimum clearance distances became effective on April 1, 2015. These minimum clearance distances are based on the voltage (in kilovolts [kV]) of the overhead power lines and are summarized in Table A:
Table A—Minimum Clearance Distances
Minimum clearance distance
up to 50
(as established by the utility owner/operator or registered professional engineer who is a qualified person with respect to electrical power transmission and distribution).
Note: The value that follows "to" is up to and includes that value. For example, over 50 to 200 means up to and including 200kV.
Before work begins in an area of overhead power lines, the local utility company or owner of the power lines should be contacted to determine the maximum voltage of the lines, so that these minimum clearance distances can be appropriately maintained during work activities.
Protection from Flames and Electric Arc Hazards
- The employer must assess the workplace to identify workers exposed to flame or electric arc hazards.
- No later than January 1, 2015, employers must estimate the incident heat energy of any electric-arc hazard to which a worker would be exposed.
- No later than April 1, 2015, employers generally must provide workers exposed to hazards from electric arcs with protective clothing and other protective equipment with an arc rating greater than or equal to the estimated heat energy.
De-energizing Transmission and Distribution Lines and Equipment
- Multiple crews working together on the same lines or equipment must either:
(a) coordinate their activities under a single worker in charge and work as if all of the employees formed a single crew; or
(b) independently comply with the standard and, if there is no system operator in charge of the lines or equipment, have separate tags and coordinate de-energizing and re-energizing the lines and equipment with the other crews.
- Employers may use insulating equipment other than a live-line tool for placing grounds on or removing grounds from circuits of 600 volts or less under certain conditions.
- Information on protective grounding for de-energized lines appears in appendices to the standards.
Electrical Protective Equipment
- The Electrical Protective Equipment for Construction standard applies to all construction work, not just electrical power generation, transmission, and distribution work. That standard also replaces the existing construction standard’s incorporation of out-of-date consensus standards with a set of performance-oriented requirements that is consistent with the latest revisions of the relevant consensus standards.
- The final rule recognizes a new class of electrical protective equipment, Class 00 rubber insulating gloves.
- The standards adopt new requirements for electrical protective equipment made of materials other than rubber.
- In addition to revising the Electric Power Generation, Transmission, and Distribution, and the Electrical Protective Equipment standards, OSHA also revised the General Industry Foot Protection standard to clarify that an employer must ensure that workers use protective footwear as a supplementary form of protection when the use of protective footwear will protect the workers from electrical hazards, such as static-discharge or electric-shock hazards, that remain after the employer takes other necessary protective measures.
As previously indicated in this article, most workers electrocuted by contacting overhead power lines are working with cranes, working on scaffolds, or using ladders. Construction employers and workers must pay particular attention to distances separating them from high-voltage lines when working on elevated equipment or structures. The following provides a closer look at working with cranes, scaffolding, and ladders near overhead power lines. In each scenario, employers should establish emergency procedures to follow if contact with an overhead power line occurs. These procedures might include keeping all unauthorized personnel away from the work area and having workers trained in cardiopulmonary resuscitation (CPR) and first aid available on-site. Workers could be reminded of the hazards and minimum clearance distances during tailgate or toolbox meetings before the start of each workday.
An employer could provide a “competent person” to observe work activities near overhead power lines to ensure that safe work practices are followed, and minimum clearance distances are maintained. A competent person, by way of training and/or experience, is knowledgeable of applicable standards, is capable of identifying workplace hazards relating to the specific operation, is designated by the employer, and has authority to take appropriate actions (see 29 CFR 1926.32(f)). Some OSHA standards add additional specific requirements that must be met by a competent person.
Using cranes near overhead power lines can be a hazard to crane operators and associated workers. OSHA data from 1984 through 1994 show that 87 electrocutions occurred to crane operations personnel. Tall equipment such as a crane with a mobile extension arm can quickly close the safe distance separating it from overhead power lines. OSHA requirements for operating cranes near overhead power lines call for specific clearance distances between work and lines of various electrical loads (see Table A), safety devices such as boom guards, insulating links or proximity warning devices, and observers, among other things. All employers and employees need to consider that all power lines as energized unless the owner of the line or electric utility company indicates otherwise.
Any crane operator and persons who work around cranes must be fully aware of the hazards of operating cranes near overhead power lines. Contact by a crane with an energized overhead power line is not only a danger to the crane operator but also to person working near the crane. Employers can increase worker awareness of the risk of injury by posting signs at the crane operator's station and outside the crane warning that failing to maintain safe minimum clearances could result in electrocution. Clearance between the power lines and cranes should be continuously monitored by a "competent person" assigned to observe the clearance and warn others if the minimum distance is not maintained.
Workers using scaffolding face hazards like those using cranes. When the worker is elevated, the safe distance between the work and energized overhead power lines is shortened. Erecting scaffolds, relocating them, and working on the platform itself all require workers to maintain safe distances from power lines. Clearance between the power lines and scaffolds should be continuously monitored by a "competent person" assigned to observe the clearance and warn others if the minimum distance is not maintained.
In addition to the scaffolding, conductive tools used by workers on scaffolds also contribute to electrocutions. When scaffolds, conductive tools, or other materials contact overhead power lines, workers receive serious and often fatal injuries. Brick masons, carpenters, painters, construction laborers, plasterers, and others who use scaffolding may risk contact with energized overhead power lines.
OSHA regulations set forth specific distances that workers on scaffolds must maintain to separate them from power lines. As indicated in 29 CFR 1926.451(f)(6), the following minimum clearances must be maintained between scaffolds and exposed, energized power lines:
- 3 feet for insulated power lines of less than 300 volts.
- 10 feet for insulated power lines of between 300 volts and 50 kV.
- For insulated power lines of more than 50 kV, 10 feet plus 0.4 inches for each kV over 50 kV.
- 10 feet for uninsulated power lines of less than 50 kV.
- For uninsulated power lines of more than 50 kV, 10 feet plus 0.4 inches for each kV over 50 kV.
In addition to maintaining safe distances, employers can help their workers using scaffolds avoid overhead power line contact by replacing electrically conductive tools and materials with non-conductive ones. Manufacturers or purchasers of scaffolds can also help by attaching conspicuous decals to each scaffold section warning about the hazards of contacting overhead power lines.
Another frequent contributor to electrocutions is ladders. Whether made of metal, fiberglass, or wood, ladders extend the reach of workers and the potential for closing the minimum safe distance between workers and energized power lines.
OSHA regulations for safely using ladders around overhead power lines require the following:
- Prohibiting the use of conductive ladders near energized lines.
- Clearly marking conductive ladders by attaching tags or stickers reading "Caution, do not use around electrical equipment."
- Using only tools designed to withstand indicated voltages.
- Keeping ladders at least 10 feet away if the overhead power line is 50,000 volts (50 kilovolts) or less. For higher voltages, keeping ladders at least 35 feet away.
In conclusion, the following information is from the OSHA Alert “Working Safely Near Overhead Power Lines” that summarizes safe work practices that should be followed to help with avoiding the dangers associated with working near overhead power lines (download PDF).
- Conduct a hazard assessment to identify and address potential safety hazards before work begins.
- Ask the electric company to de-energize and ground overhead power lines.
- Educate workers on safety procedures and requirements.
- Know the safe working distance for workers and equipment.
- Use non-conductive wood or fiberglass ladders.
- Wear personal protective equipment, such as rubber insulating gloves and insulating sleeves, and industrial protective helmets.
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