Eskom has announced that it will implement stage 2 blackouts from 5pm on Tuesday.
The power utility says peak supply constraints are to blame.
There is also the possibility of higher stages should any breakdowns happen.
Generation units at Kusile and Arnot power stations are expected to return to service on Tuesday.
On Monday, a unit each at Arnot, Grootvlei, and Matla power stations had either tripped or were taken offline for repairs.