Eskom has escalated load shedding to Stage 6 between 4pm and 5am until further notice.
Stage 4 load shedding will also be implemented between 5am and 4pm during the day.
The power utility had been implementing various stages of rolling power cuts since the beginning of the year.
“Seven units tripped [on Tuesday], of which three have returned to service. In addition, the return to service of three other units has been delayed.
“Unit 1 of the Matla Power Station will be shut down [on Tuesday evening] to repair a boiler tube leak,” Eskom said.
The electricity supplier said it will communicate “as soon as there are any significant changes” to the power grid.