Why do some hanging electrical wires have balls on them?

Question

I've always wondered why some electrical wires that hang and pass above water such as rivers have huge color balls. I always thought that if the wires happen to fall into the river, that they would be easy to locate because they would float. But this theory was put down when I saw electrical wires with color balls above ground and not near water.

Does anyone really know why electrical wires have these colorful balls?

Answer 1

The large globes are known as aircraft warning markers. They are used to make the power lines more visible to pilots. When you or I look up at the wires, they are seen against the blue (or gray) sky. When pilots look down, the wires tend to blend in with the ground.

The balls generally range is size from 30" to 52" in diameter.

You'll often see the markers on wires that are inline with the end of a runway. While there is plenty of clearance for the planes and their glide slope, many locations put up the markers anyway. They will also appear over large river crossings where it is common for pilots to fly along the path of the river.

Any structure that exceeds an overall height of 200 feet (ft) above the surrounding terrain should normally be marked. The FAA may also recommend marking a structure of lesser height located within 20,000 ft of an airport or 5,000 ft of a heliport.

Answer 2

Above water, for sailboats with high masts, to avoid them.
On land, for low flying aircraft, such as close to airports. It shows them where the wires are.

Answer 3

Those balls on the wires are for aircraft. Planes and helicopters. They are usually in flight paths of hospitals or private landing fields or pads.

Answer 4

I'm not sure, but I think it might be to aid low flying aircraft in their abitlity to spot and avoid the wires.