Birds and Wires

Birds and WiresFrom the childhood many of us wonder why birds can freely sit on power lines. How can flocks of birds sit on high-voltage lines and stay alive without being killed by electric shock? Do they know a secret? Or are bird arms insulated? Actually, we can find the answer in electro dynamics. An electric shock occurs when electric current passes through a body. Danger lies in a great difference in potentials at points of contacts with conductors. Power transmission lines carry alternating current. When a bird sits on a line it contacts with one wire only. There is no grounding and no difference of potentials. Or, to put it in other words, cable voltage is in line to that of a bird. That's why birds do not suffer from electric shocks. Generally, wires are located at a certain distance from each other preventing the contact with two wires at a time. The risk of the difference in potentials relates to large birds only. In addition, a body of a bird sitting on a wire is a kind of circuit branch. Or you may say that a bird is parallel-connected to the circuit. As the bird body's resistance is many times as much as the cable resistance, current flowing through the bird and the difference in potentials between bird arms are very small. Therefore, there is no risk of electric shock. However, the situation is just the other way round for humans. Firstly, to touch the wire humans need a some kind of support which usually serves as a grounding point. Even if such support is insulated from the ground, avoid touching wires as the difference in potentials between hands is many times as much as between bird arms. That's why electric shock is unavoidable. Do not check bird abilities yourself!

Category:

Science & Technology

Tags:

• cable
• electricity
• grounding
• security
• voltage
• voltage swing

[icedyoubro]

birds on receive electric shock when there are 2 separate birds on 2 separate lines at different voltages. as said in the video it creates a potential difference which is the only way to receive and electric shock.