1.   At certain times of the year, major transmission lines become overloaded, usually because of high demand due to extreme heat or cold in urban areas.

2.   Telephone lines are overloaded understaffed.

3.   That requires adjustments to the system so that electricity can spread evenly across the grid, rather than overload other lines, causing more disruptions.

4.   An official at the Post, Telegraph and Telephone department in Baghdad said lines were overloaded as Iraqis tried to call relatives abroad.