Power Cut

Load shedding, or load reduction, is done countrywide as a controlled option to respond to unplanned events to protect the electricity power system from a total blackout. While we generally use the word blackout loosely to mean “no lights” in our local area, a country-wide blackout has much more serious consequences, which can occur when there is too much demand and too little supply, bringing the power system into an imbalance – tripping the power system in its entirety.

http://loadshedding.eskom.co.za/LoadShedding/Description