The feet of the bird are not that far apart therefore the potential difference between the point of contact with the wire is not much(the usual length of a transmission line is about 60 km for a voltage of 20kv therefore the ratio of the distance between the feet of the bird and the length of the wire is very small, the same goes for the ratio of potential difference). Since the potential difference is low power dissipated is also very low (power is directly proportional to square potential difference) hence the bird survives.
However if the bird was sitting on two wires(live and neutral) with one feet on one wire and the other feet on the other wire it won’t survive. The live and neutral wires are out of phase with one another hence the potential difference is high in this case which leads to high dissipation of power


Maybe in some cases. When the bird alights on the wire near a pole and it’s wing or tail feathers touch the pole. Feathers are electrical insulators. But if wet they would become good conductors. Consequently the electrical circuit would be complete through the bird’s feet, body and feathers and the pole
One may note that pure water is a poor conductor. One assumes that the bird has not given itself a distilled water bath.


Railway wires are usually around 25000vDC
And this image shown previously is about 440000vAC
So, railway wires are not dangerous unless they touch another conductor and live wire simultaneously


The power plant uses earth as a return path.

If one were using an isolated power system eg. a generator without earth, then one would have to touch both wires of the generator to get a shock. Touching any one wire and earth will not give you a shock, subject to the breakdown voltage of the generator to earth was substantially higher than it’s operating voltage.
Breakdown voltage: Voltage at which an insualtor between two isolated live points fails.


Already posted a link on the subject matter. Specifically IEEE’s paper making the claim is deeply flawed as they merely checked DC at 25v and then linearly extrapolated to higher voltages. They have also made numerous questionable assumptions, which are pointed out in the above link.


Birds have pneumatized or “hollow” bones. This is because respiratory air sacs form air pockets within the semi-hollow bones of the bird’s skeleton. Flightless birds such as ostriches and emus have pneumatic femurs but the rest are marrow filled, similar to humans. But the bone structure of birds is not the reason that they do not get electrocuted on power lines rather has to do with the potential difference between two point.



Great explanation @jtd sir :clap::clap::clap::pray:

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Neutral wire is at zero potential. Neutral is not out of phase with the live wire.
In 3 phase systems there is a 120^{\circ} phase shift between the three phases, but none wrt ground.


Yeah that is correct my bad.


How does a cell (battery) generate electric current that illuminates a torch bulb?
And what did the latest Nobel Winners do to turn the table? Can we trace the history of chemistry to understand what is electricity (and how nerve conducts…!!!).

How we made the Li-ion rechargeable battery

Nature Electronics volume 1 , page204 (2018) | Download Citation

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Progress in portable and ubiquitous electronics would not be possible without rechargeable batteries. John B. Goodenough recounts the history of the lithium-ion rechargeable battery.