Eskom said early indications were that a fire, which engulfed a substation in Balfour, Mpumalanga, were as a result of a lightning strike.
The incident happened on Sunday around 2pm, and Eskom was not aware of any injuries, said spokesperson Dikatso Mothae on Monday.
“Electricity supply to some 5,800 Eskom customers and the bulk supply to Dipaleseng Municipality were affected.
“Information regarding the full extent of the damage, impact and the expected restoration time must still be established,” Mothae said.
She said investigations would begin as soon as the facility was “cooled down and safe to access”. This was expected to be by mid-morning on Monday, she said.
“We place a high value on the safety of our customers, contractors and employees, for this reason, safety will be prioritised.
“Eskom will keep the customers informed of the progress and remains committed to attend to the matter urgently.”