Electricity and trees: How close is too close?

As our neighborhoods and farmlands continue to mature, so do the trees that make up and characterize the property. Yet, this majestic flora can present danger when growing near transmission lines. Unfortunately, trees growing near power lines can cause a fire, as well as pose an electrical hazard to anyone in contact with the tree at ground level. Trees don’t have to physically touch an energized power line to be dangerous. Electricity can arc from the power line to nearby trees given the right conditions, such as a voltage surge on the line from a nearby lightning strike.

At Western, we ensure our transmission line rights of way—more than 17,000 miles of high-voltage line—are safe for our employees and the public. Our transmission lines all carry electricity at voltages 50 to more than 100 times the electricity flowing in neighborhood power lines.

To keep these lines sending power to millions of homes across the West, our line crews regularly patrol the lines to make sure the equipment is in good shape and conditions on the rights of way below are safe for maintenance and energy purposes.

So how close is too close for a tree?

The National Electric Safety Code specifies the minimum distances between power lines and nearby objects—including trees—based on the line’s voltage level. The code requires greater clearances for higher voltage lines.

A graphic demonstrating how far trees should be from transmission lines of various voltages

Call it how you see it…

So the next time you’re working on your land or strolling through your neighborhood, be mindful of trees that may be too close to the power lines. If you do find one, stay clear and call your local utility. In an emergency call 911 or your local utility.

6 Comments

  • By Wettbewerbsrecht in Köln, December 7, 2010 @ 10:51 am

    Thank you for the interesting insights. This is the first time I heard about this problem.

  • By Car Rental CostaRica, December 28, 2010 @ 9:40 am

    This is pretty interesting and good to know when you walk in the woods

  • By High Pressure Pumps, July 18, 2011 @ 9:24 pm

    Living in the south and near the gulf. I always wondered how much the electric power companies can save by being proactive and trimming a lot of the trees near power lines. All companies should follow.

  • By Tim @ Local Law, May 21, 2012 @ 10:12 am

    University of Washington scientists have discovered a new source of electricity: Trees.

    In an experiment that will seem familiar to students of the potato, the scientists stuck one electrode into a bigleaf maple, and another in the ground, and saw that the tree generated a tiny stream of electricity — a few hundred millivolts.

  • By sewa kamar orchard, June 11, 2012 @ 8:23 am

    Good info, a lot of thanks to the author. It can be incomprehensible to me now, but in common, the usefulness and significance is overwhelming. Thanks again and great luck! sewa kamar centrepoint orchard

  • By Meiman, July 9, 2012 @ 11:07 am

    I would check out several of the Department of Energy’s blogs. A good start is here: http://energy.gov/news-blog

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