The majority of outages during inclement weather are caused by falling or damaged trees. Limbs, branches and weak or diseased trees can bring down wires if they fall in any kind of weather. In fact, trees and falling limbs are the top causes of unscheduled outages on clear days as well. Electrical service can be interrupted for thousands of customers due to a fallen limb that damages a power line. An effective, responsible tree maintenance program is critical to our successful and safe delivery of electric service. The tree trimming and removal work we perform is required by regulations that mandate minimum clearances between trees and power lines.
We implement our tree maintenance program because safety is one of our top priorities. When trees come in contact with a high voltage power line, they can also become energized which could potentially result in sparks or fires that could cause harm to people, animals, homes or buildings. Our tree maintenance program reduces risk and minimizes outages caused by falling trees, branches or limbs, and improves the reliability and safety of your electric service. By trimming and removing trees around power lines, we can reduce the chance of trees, branches or limbs falling on power lines.
Our tree maintenance program is a proactive way to prevent trees, branches or limbs from falling on power lines. Depending on the tree species, sometimes it is necessary to remove trees and plants regardless of height. Some tree species can grow up to 10 feet per year and can grow close to power lines in a very short time. Any tree that can grow within an unsafe distance from lines creates a safety hazard and could cause a power outage for thousands of customers. This is especially true along high-voltage power lines that affect large areas and have greater consequences if damaged.
It depends on the type of trees but some species can grow up to eight to ten feet in a year. It is important to proactively remove them before they cause damage to the system or a safety risk. Certified arborists review each tree to determine what action, if any, is necessary.
Each tree is examined individually by certified arborists and the determination is made based on a variety of factors including the species, the direction branches are growing and how much of the tree must be pruned. If it is necessary to trim more than 25 percent of a tree, state law requires utilities to remove the entire tree. In many cases, it is because your neighbor’s trees meet or exceed clearance specifications and do not threaten power lines.
Our tree trimming is performed in accordance with the standards and practices outlined by the American National Standards Institute (ANSI) Publication A300. This standard for line clearance is followed by nearly all electric utilities in the United States. We also work with the DC Department of Transportation, Urban Forestry Administration and the Maryland Department of Natural Resources to comply with their tree-pruning practices.
The Public Service Commission oversees our tree maintenance work.
Rule Making No. 43 refers to the vegetation management regulations adopted by the Maryland Public Service Commission (PSC) to increase reliability. RM 43 requires utilities to be more comprehensive in their tree trimming around electric facilities including power lines, poles, transformers, substations and rights of way. The vegetation management standards, which took effect in 2012, were developed by a panel that included representatives from consumer advocacy groups, the PSC, the Office of People's Counsel, various counties and power utilities serving customers in Maryland,. We immediately made changes to our process in order to comply with the new regulations, which include pruning to a four-year growth cycle next to and under most power lines. High-voltage lines will require clearances of 15 feet below and beside lines and "blue sky" clearance above, which means that there must be total clearance above the line. Maryland law requires the removal of trees when more than 25 percent of the tree canopy must be pruned. Under the regulation, we are required to notify owners or occupants at least seven and no more than 120 days before we plan to begin work on their property.
Trimming cycles are dictated by states. Our cycle in Maryland and Delaware is based on a four-year rotation, meaning that approximately one quarter of the public space trees are maintained each year. Each tree’s size, shape and growth rate are taken into consideration in our tree maintenance program. Maintenance may include pruning or removing branches that are too close to power lines or, in some cases, removal of entire trees.
The amount of pruning or trimming varies based on a tree’s relative location to the power lines as well as the type, growth habits and health of the tree. Maryland regulations set clearances based upon the voltage of an electric utility’s equipment. The following diagrams illustrate examples of minimum tree clearance required for certain facilities.
Tree pruning near electric power lines can result in severe injury or death. There are specific mandates for how tree pruning must be done around power lines. You should not attempt to prune any tree or vegetation growing near or through power lines. You are required by law to call us at 202-833-7500 in Maryland or 800-375-7117 in Delaware if you plan to work within 10 feet of power lines or utility poles.
Our tree maintenance program is consistent with electric utility best practices and complies with national tree care industry and utility vegetation management standards. RM43 specifically mandates that we use a four-year-growth clearance schedule in our Maryland service area. Our tree pruning contractor trims, and in some cases removes, trees that could potentially come in contact with power lines or other electrical equipment. Certified arborists evaluate tree growth around each pole in order to create an effective work plan for tree crews. They look for trees and vines that could eventually develop a conflict with the electric equipment. They also look for dead, dying or hazardous trees and tree conditions that could interfere with power lines and cause power outages.
Customers will receive at least one form of notification depending on the scope of the work. Notifications vary and could include letters, door hangers and knocks on the door. If a tree poses an imminent safety hazard or impact to the reliability of the electrical system, we will take reasonable steps to obtain consent from the owner or occupant of the property before any trimming or tree removal work is done. The safety of our customers and employees are most important.
Each tree is examined individually by certified arborists and the determination is made based on a variety of factors including the species, type of energized facility, the direction branches are growing and how much of the tree must be pruned. If it is necessary to trim more than 25 percent of a tree, state law requires utilities to remove the entire tree. We have enhanced our tree and vegetation management efforts since 2012 to meet the standards set by RM 43. These regulations have altered some of our previous practices in that some trees we would not have pruned in the past now have to be trimmed or removed in order for us to comply with the revised regulation.
Our tree pruning is performed adhering the standards and practices outlined by the American National Standards Institute (ANSI) Publication A300. This standard for line clearance is followed by nearly all electric utilities in the United States. We also work with the DC Department of Transportation, Urban Forestry Administration and the Maryland Department of Natural Resources to comply with their tree-pruning practices.
We have a large staff of trained foresters and certified arborists who oversee the work of our contractors. Our contractors are required to adhere to tree care standards established by American National Standards Institute (ANSI) A-300. Our methodologies are based on Best Management Practices (BMPs) established by the International Society of Arboriculture (ISA). Utility vegetation management arborists are required to abide by Safety Standards set in ANSI Z133 and they are regulated by the Occupational Safety & Health Administration (OSHA).
Our contractors will remove tree limbs and debris during tree maintenance work. We are not responsible for removing trees, branches or limbs that fall or damage our power lines from events beyond our work or from storms.
Directional pruning is the process of cutting branches that grow toward power lines while leaving the ones that have grown away from them. Directional pruning attempts to guide future growth away from power lines, requiring less pruning in the future.
Wire location, limb size or branch configuration may make it necessary to remove limbs back to the tree’s trunk. The tree species, its position in relation to our electric facilities, and line voltage are all factors in determining how much limb removal is required. Figures 3 and 4 show the basic forms that lateral pruning can take depending upon where the tree is in relation to the power lines. When trees are planted directly beneath power lines, branches must be cut back until a fork (crotch) in the tree is reached (see Figure 3). This is a natural junction that allows the arborist to direct new growth away and permits large trees to coexist with power lines. If the tree is next to power lines, then lateral cuts are made to direct the tree growth back and away from the power lines (see Figure 4). Branches above the power lines are directed up and back, while those below the power lines are directed down and back or removed to the trunk. Next season’s growth is then concentrated in the direction of the lateral cuts and away from the wires. Future pruning refines this procedure and improves the shape of the tree. These methods usually mean cutting fewer branches but achieving better electrical service reliability for our customers and it is healthier for the trees.
When a tree that grows too large or too tall is planted under or near electrical power lines, it can cause power outages, property damage or even injury to people or animals. The Arbor Day Foundation advocates a policy of “Right Tree in the Right Place,” under which all trees are planted where they can thrive and will not interfere with essential public infrastructure such as electric power lines. Pepco advocates this policy as well and has been certified as a Tree Line USA Utility since 2001. For more information about this program, visit www.delmarva.com. If there is a pad-mounted transformer (green metal box) in your yard, please make sure there is a 12-foot cleared space in front of the door, free of vegetation, to permit our crews to service the transformer. It is important to call your utility locating service before any hand digging, excavating or boring occurs. This is done to ensure no underground lines are hit during the digging process. Call Miss Utility at 811.
We responsibly apply herbicides when needed. Using herbicides approved by the Environmental Protection Agency, we also use appropriate equipment and follow recommended methods.
Since we do not remove tree stumps, there should be no disruption to the soil.
Not usually, however, there are times when we do plant trees in the right-of-way. Sometimes it is the result of a permit requirement and other times it is at the request of local or county department of transportation.
We do not recommend specific contractors. We encourage our customers to confirm that contractors are licensed and insured and that they comply with all applicable laws, codes, ordinances and permits including the Occupational Safety & Health Administration (OSHA) regulations and American National Standards Institute (ANSI) standards.
According to Black’s Law Dictionary, an easement is a right of use over the property of another.
We will make all reasonable efforts to work with you before trimming or removing trees on your property and/or our easement. An effective tree maintenance program is critical to our safe and reliable delivery of your electric service. We trim and remove trees that will grow into or interfere with electric wires and other equipment. If we have an easement to perform the work on your property, we will work with you as best we can but our obligation under RM43 is to obtain the required clearances.
Sometimes trees that appear to be on a customer’s property could be in the public utility easement or public right-of-way.
If a tree on private property needs to be removed, the property owner’s permission must be obtained. We will, however, trim trees on private property where tree limbs on branches encroach on our easement. Our easements on properties along the power line route give us specific rights to maintain those rights-of-way and keep them clear of trees and vegetation that could threaten the safety and reliability of the system.
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We will only trim or remove trees from a person or business’s property if it poses a threat to an electrical power line.
We advocate the same policy as the Arbor Day Foundation – “Right Tree in the Right Place.” When selecting a tree, consider the ultimate mature height of the tree. Small trees, those less than 25 feet tall, are the only trees that should be considered for under or near power lines. Examples of small trees suitable for our area include dogwood, redbud and flowering cherry. Medium trees that grow to a height of 40 feet or less, such as honey locust, service-berry or hornbeam, should be planted at least 20 feet from power lines. Tall trees such as maple, sycamore, oak, spruce, pine and birch should be planted well away from wires – more than 50 feet to the side. Check with a local nursery for a more complete list.
We do not recommend specific contractors. We encourage our customers to confirm that contractors are licensed and insured and that they comply with all applicable laws, codes, ordinances and permits including OSHA regulations and ANSI standards.
If you received a notice hung on your front door notifying you of tree-trimming activity in your neighborhood, you should contact the arborist listed on the notice. Otherwise, you may contact us at 202-833-7500 in Maryland or 800-375-7177 in Delaware and ask to have someone in our forestry department call you.
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We will investigate requests for removal of tree limbs that may endanger our power lines. Our contractor’s inspectors will explain to the property owner if any tree work is needed and if so, whether the tree needs to be trimmed or removed. Please call 202-833-7500 in Maryland or 800-375-7117 in Delaware with any questions or concerns.