"So suppose the line had been hit by a couple of million volt lightning strike?"
The upper, high voltage lines are typically protected against lightning strikes by surge (lightning) arresters. The lower voltage lines underneath are shielded by the presence of the higher voltage line on top. Lightning hits the highest point.
But if the upper 12 kV (?) line hit a 240 V line, the 12 kV surge protectors would see no unusual voltage.
Biting the hand that feeds IT
