Widespread power cuts have hit Iraq at a time when the country is suffering scorching summer temperatures.
The electricity cut on Friday was caused by the failure of a major power line, local media report.
The capital, Baghdad, and southern provinces have been particularly badly affected.
Protesters have taken to the streets against the outages - anger over power cuts has previously fuelled mass street demonstrations.
Earlier this week Electricity Minister Majed Mahdi Hantoosh submitted his resignation as political pressure built over repeated power cuts across the country.
Iraq's electricity ministry has cited a number of causes for the prolonged cuts. They included terrorist attacks on electricity lines, shortages of fuel for power stations, and the suspension of energy supplies from neighbouring Iran.