JOHANNESBURG - Some residents of Soweto are still without power.
They were cut off when the Zola substation caught fire on Wednesday.
Eskom says a preliminary investigation shows two transformers were vandalised.
It says transformer oil was stolen from one of the units.
The utility says it will continue to assess the extent of the damage.
Dobsonville, Emdeni, Jabulani, Moletsane, Mofolo North, Naledi, Tladi, Zola and Zondi were affected.
Eskom says it continues to battle with theft and vandalism of transformers.
It's had to replace 400 of them since the beginning of the year.
eNCA's Hloni Mtimkulu is on the ground.