For this to occur, the electrical line must be energized at the time that fire hits it.
Several other factors affect the locations where electrical faults occur.
The elevation of an electrical line has a strong effect on its exposure to heat, since temperatures in a fire are generally highest near ceiling level, except in the immediate vicinity of the point of origin.
("Energized" usually refers to a conductor being connected to hot power, as opposed to neutral.
Investigators distinguish between electrical arcing and copper that melted due to the high temperatures of the fire.