What are colorful Aerial marker balls and why are they used?

why aerial marker balls are used on power lines

Have you ever noticed that some colorful balls are hanging on the high-voltage power lines? While driving down the highway, there may have been many times when you noticed a series of colorful balls attached to the power lines. Almost all of us have seen those colored (mostly orange, red, yellow, and white) balls on high-voltage transmission lines. You might have a question in your mind, What are these colorful balls, and why are they hanging on these power lines? 

What if I tell you that these colorful balls are placed on those wires just to enhance the decoration of the city? I know that you won’t agree with me, and of course, This is not the actual reason. But yes, they look very beautiful to those wires.

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Well, those colorful balls are called Aerial Marker Balls, or Visibility marker balls, or simply Marker balls. They are also famous for one more name which is the Span guard ball. 

What are Aerial Marker Balls and Why Are They Used on Power Lines? 

The colorful balls used on high-voltage power lines are known as Aerial marker balls, Visibility marker balls, or Marker balls. Sometimes they are also pronounced as “Span guard balls”. They have weight around 7.7kg (17 pounds). These are colorful marker balls, and the most used color is International Danger Orange. However, Yellow, Red, and White colored balls are also used in specific situations depending on the surroundings for clear visibility. 

When any helicopter or an aircraft flies at low altitudes, it is very difficult for pilots to see the transmission lines clearly. So, to identify the wires these colorful marker balls are placed on power lines.

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Aerial marker balls are used for safety purposes only. They are placed on power lines to make the conductor crossings visible to aircraft pilots. They save lives and infrastructure by making transmission lines and communication lines visible to helicopters and low-flying aircraft. 

Generally, helicopters and aircraft fly at a high altitude, but they tend to fly at low altitudes in some locations, like rivers, hilly areas, deep valleys, highways, and runways. To protect them, these Aerial marker Balls are used on those power lines. That is the exact reason why marker balls are installed on the power lines, especially in the case of overhead High-voltage transmission lines and communication lines crossing major highways, mountain passes, deep valleys, rivers, and runways. 

Installation of Aerial Marker Balls on Power Lines 

Well, the main challenge is How these balls are installed at such heights and difficult locations on power lines. If this question arises in your mind, then you might also think about the use of cranes and lifts, but here I remind you once again that these Aerial marker balls are not used on every transmission line. They are used only in locations where helicopters and aircraft tend to fly at low altitudes and hence cranes cannot reach everywhere, especially at such a difficult location. 

installation of aerial marker balls

So, these balls are installed on power lines and also on communication lines with the help of helicopters and skilled persons as shown in the above image. These balls are made up of hard plastic and hollow from the inside. So, they are tightly screwed from both sides. 

Features of Aerial Marker Balls 

These are some key features of colored aerial marker balls: 

  • The weight of an Aerial marker ball is around 7.7 kg (17 pounds). 
  • These are hollow spherical balls made up of hard plastic material that can withstand high temperatures. 
  • Generally, the diameter of these balls is around 36 inches but for less extensive catenary wires like on rivers, and lakes, the diameter of these balls is 20 inches. 
  • Generally, Aviation orange colored Aerial marker balls are used. However, Yellow, Red, and White colored balls are also used in specific situations depending on the surroundings for clear visibility of conductors.
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Hey, I'm Satish Gupta an Engineer by profession and blogger by passion. I am writer and founder of this blog, Here I publish contents related to Electrical and Electronics Engineering..

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