Stage 6 loadshedding will be implemented from midday until further notice, Eskom announced.
"This is due to a high number of breakdowns since midnight, as well as the requirement to strictly preserve the remaining emergency generation reserves," the utility said.
Eskom has overspent its budget for diesel, which fuels gas turbines. The turbines provide emergency power to prevent loadshedding. Since 1 April, the company has spent R12-billion on diesel against a revised budget of R11.1-billion.
It has no more cash to buy new diesel stocks until 1 April next year.
Eskom has asked the National Treasury for R19.5-billion to buy diesel to fuel its emergency power plants, but last week Finance Minister Enoch Godongwana said the request will probably be denied.