I am from a city of overhead cable chaos like this.

I often come across news of people including children being electrocuted by touching overhead transmission lines while playing in the rooftop, while picking up a ball from a tin roof etc.
I feel both sorry and confused when I read these news. I have always known that electrical wires have rubber insulations around their whole body. If that is the case in general, how can people die merely from touching a live wire? Aren't there supposed to be insulation? Do the accidents take place due to uninsulated cables or worn-out insulations?

I often come across news of people including children being electrocuted by touching overhead transmission lines while playing in the rooftop, while picking up a ball from a tin roof etc.
I feel both sorry and confused when I read these news. I have always known that electrical wires have rubber insulations around their whole body. If that is the case in general, how can people die merely from touching a live wire? Aren't there supposed to be insulation? Do the accidents take place due to uninsulated cables or worn-out insulations?