The rain was finishing, the peak of the thunderstorm was far behind and it seemed like all potentially dangerous moments were over. A child was walking in the street with an umbrella and then a lightning stroke just close to him. Luckily, nothing happened to the teenager. But why? We will study this situaton in detail.
On a time-lapse video, you can see several "reverse strikes" in the form of bright flashes which create a strobing freeze effect on the video. The electrostatic charge was probably negatively charged - lightning from the cloud to the ground. Positively charged lightning is more powerful- we are talking about a billion of volts and usually strikes as one mega-charge.
After the strike, electric current is distributed over the ground in circular arcs. The voltage value of arcs reduces with the growth of distance from the strike point, and the current in the ground can distribute to the distance of 15 meters from the initial strike point. It means that the discharge with the current intensity of about 20 000 Amperes can cover the square of up to 730 square meters.
Obstacles on the ground can prevent the distribution of the discharge. In this case, the swimming pool and the concrete blinding might reduce the potential damage area.
And we should not forget about the famous folk wisdom "Luck favors the prepared". It is better to secure your house and install lightning protection system in order not to rely on luck.
Do you have questions or need to calculate lightning protection and grounding for a single-family house? Please contact our ZANDZ Technical center!