SA is currently on loadshedding level 6, Eskom said in a statement minutes ago.
There are leaks in boiler tubes of at least 50% of electricity generating units (5).
The electricity utility also said a delay in returning 3 units due to their maintenance, exacerbated the situation.
Unplanned outages currently account for 17, 798 Megawatts.
Units out for maintenance are at 6, 653 Megawatts (MW).
Peak electricity tonight is expected at around 25,087 Megawatts. Eskom said its teams are at work to try and restore at least 2,400 MW to the system by Monday morning.
It is not clear what caused such a huge leak to so many generating units, simultaneously.