Vegetation such as trees, shrubs, vines and brush can create serious safety hazards and costly repairs for utility companies when overgrowth encroaches on power lines or energized equipment. When vegetation  grows onto live lines, it can cause major damage and power outages. In drier areas, we are well aware that trees coming into contact with power lines can spark wildfires. Therefore, vegetation management and tree trimming operations are crucial to maintaining power and the integrity of energized equipment.

According to utility company Southern California Edison, “Vegetation management is a broad term that describes work to minimize the impact trees and vegetation have on providing safe and reliable electric service. It includes hazard tree assessments, tree pruning and removal, brush removal, and weed abatement. In support of safety, we regularly trim or remove trees that are dead, dying, or diseased, or growing near or under power lines.”

Rules and standards

However, tree trimming and line clearance operations come with their own safety hazards. Since too many people doing this work are killed and injured each year, the Occupational Safety and Health Administration has standards in place addressing tree trimming and line clearance safety.

Paragraph (R) of the electric power generation, transmission, and distribution (CFR 1910.269) standard addresses line clearance personnel, equipment requirements and minimum approach distances (MAD) for tree trimming operations. MAD for electrically unqualified workers is outlined in the OSHA standard 1910.333(c)(3)(i). The agency has three different qualification levels for tree trimmers: unqualified employees, 269-qualified employees and line-clearance tree trimmers.

Unqualified employees are required to maintain MAD of at least 10 feet from overhead power lines, and 269-qualified employees are required to use specialized skills and procedures to safely trim trees. Line-clearance tree trimmers have received specific training that allows them to work within 10 feet of energized power lines and equipment. According to the OSHA eTool Line-Clearance Tree Trimming Operations, these workers are required to:

Determine the voltage(s) of any lines that may pose a hazard before work begins. Alternatively, all lines must be considered as operating at the voltage of the line with the highest voltage.

Ensure their body parts and any ladders, platforms or aerial devices being used remain outside the minimum approach distance from any energized part.

Use only insulated tools and equipment to remove branches and limbs that are in contact with, or are within the minimum approach distance of, energized parts.

Not work during adverse weather conditions (high winds, icing, thunder and lightning, etc.) that make the work hazardous.

These workers need to be trained and recertified at least annually. All workers involved with line clearance and vegetation management must wear appropriate PPE, which may include approved fall protection, leg protection or chaps, goggles or safety glasses, a face shield and hearing protection. These employees should also be familiar with MAD, aerial lift and ladder safety.

Keep tools used for line clearance clean and dry. The chainsaw is the most common tool used to trim branches, and workers must follow all manufacturer’s instructions, keep the engine off when carrying and refueling and keep away from ignition sources with the engine off.  When cutting, workers must keep their hands and feet away from the wood, never operate the saw above the chest and prevent kickback by inserting the saw fully and not cutting with the upper section of the bar. Tree trimmers should always stand at an angle with firm balance to avoid getting hit in the neck or head, in the event kickback does occur.

When cutting, workers should ensure that limbs are lowered with a rope if they can’t be dropped safely. Partially cut branches should never be left in a tree and need to be dropped or lowered to the ground. Workers on the ground should never turn their backs on a tree when branches are being cut. If an entire tree needs to come down, employees should use the two-tree rule. This means that the area of two tree lengths is clear of people or things.

Finally, since line clearance and tree trimming work is done outdoors, it is imperative that employers and employees are aware of environmental hazards and take steps to avoid heat or cold stress and exposure to dangerous plants, insects and other wildlife.   //

For more on tree trimming, read “Smart Choice” from the March 2021 issue of Line Contractor.