This Is Why You See Colored Balls on Power Lines

They're strung across electric wires all over the country. But just what are the balls on power lines for? We solved the mystery.

There’s something about driving that allows your mind to wander. Maybe you’re considering your dinner plans, or contemplating intriguing questions. Like: Why do you see metal wrapped around trees? Why are there colored squares on toothpaste? And what are those balls on power lines?

You might drive past the same electrical lines daily without knowing the purpose of those colorful spheres. Are they bizarre pieces of public artwork or a scale model of the solar system? Perhaps they’re there to weigh down the power lines that might otherwise blow in the wind.

We learned more about these colorful markers and why they’re strung on power lines across the country. And it turns out, there’s a simple explanation.

What Are the Balls on Power Lines?

Known as marker balls, these indicate where power lines are so low-flying aircraft can avoid them. Also called aerial marker balls or visibility markers, the Federal Aviation Administration (FAA) requires them on power lines that cross canyons, lakes and rivers, as well as those that surround airports.

But why are they different colors? The FAA found aviation orange, white and yellow offer the greatest visibility, but colors must be as conspicuous as possible against the background landscape. That means you might see other colors, depending on where you live.

So the next time your passenger asks, “Hey, what are the balls on power lines for?” you can answer that they’re saving lives.

What Are the Balls on Power Lines Made Of?

For maximum durability and color fastness, the balls on power lines are plastic. Plastic also doesn’t conduct heat or electricity, making it a good electrical insulator.

You might be surprised by their size. Much like a traffic light, these colorful markers are unexpectedly large — between 20 and 36 inches (about the circumference of a basketball). But you wouldn’t bounce anything this heavy. These weigh between 11 and 17 pounds each!

How Long Have Those Colorful Balls Been Hung on Power Lines?

Nearly 50 years.

In the early 1970s, then-Arkansas governor Winthrop Rockefeller was on an airplane with the head of the Arkansas Department of Aeronautics, Edward Holland. Just before the plane landed, Rockefeller noticed electrical wires close to the aircraft. He asked Holland to develop a way to make electrical wires more visible to pilots.

Holland enlisted an engineer named Jack Rutledge to create brightly colored balls that could be placed on electrical and telephone lines without slipping in the wind. By the 1980s, Rutledge’s company had become one of the world’s leading suppliers of visibility markers.

The invention has saved countless human lives in the decades since, but Canadian geese have also benefited. Before the markers came into common use, geese would often fly into or land on power lines. Marking the lines also helped many of our feathered friends.

Reader's Digest
Originally Published on Reader's Digest

Chloë Nannestad
Chloë is a lifestyle writer covering crafts, holidays, beauty, and amazing products for When she's not scouring the Internet or reading product reviews, she's planning her next backpacking trip and thinking about getting a dog.