The electrical current that circulates through high-voltage cables is like a river of electrons that flows at high speed and always along the easiest path, ‘preferring’ conductive materials that offer little resistance.
Since wire is a good conductor, electricity can travel great distances – from a power station to our home – in a very short time.
If the path is broken, the electrons will look for an alternative. For example, if the cable is cut with metallic scissors, the electrical flow will not be able to follow the usual path and will pass towards the scissors, from them to the person holding them, to finally arrive. to Earth.
Another fact that must be kept in mind is that when two elements with different voltages are joined, the forces tend to equalize, the flow of electrons passing through any element that is minimally conductive.
we are bad drivers
The current that passes through a person holding a cable with both hands has three components: the capacitive current (it is assumed that the human being has an effective capacitance), the resistive (the electrical resistance of the cable) and the one due to the change of phase between the two support points.
It is calculated that for a very high voltage cable (500 Kv), which is the one that connects power stations and distribution stations, the capacitive current is around 9 mA, the resistive current is 0.02 and that due to the change in 0.5mA phase. Therefore, the total current is about 9.5 mA.
Electrocution or electrical trauma is the damage that occurs when an organism becomes part of an electrical current. It is estimated that the current on a man who touches a very high voltage cable with both hands can be about 7 mA, a figure that gives him an unpleasant sensation but one that can be endured. When it rises to 16 mA, the human being is forced to release the cable and if it exceeds 30 mA, death occurs due to ventricular fibrillation.
If someone touches a high voltage cable and offers a path to another cable, or to the ground, the shock will be enormous, and since we are not good conductors of electricity, there will be a rise in temperature that will char the person.
And with the birds… the same?
Birds are generally small animals, so when they land on power lines there is little chance of simultaneously touching the ground or the other wire. Usually they are perched with their legs on a single cable.
When this happens, the electricity has two options: flow through the copper, ignoring the animal, or through its body, from one leg to the other. Because the animal is not a good conductor, the electricity “does not gain anything” by flowing through the legs, that is, it would not be able to travel the cable more quickly.
The situation would change if the bird were able to touch both wires at the same time, either by supporting itself with both legs or by touching the other wire with a part of its body, for example a wing. In such a case, the difference in potential would make the bird a good option and it would be crossed by the flow of electrons.
In conclusion, large birds are the most vulnerable to electrocution, since they can reach the two wires with different parts of their body, either by opening their wings to take flight or by leaning on power lines.