Around 20,000 households in south-east Berlin remained without electricity early on Wednesday following a widespread outage, local grid operator Stromnetz Berlin said.
Power was gradually restored overnight after the outage, which began more than 24 hours earlier and is believed to have been caused by an arson attack on high-voltage cables. Originally, about 50,000 homes were affected.
Stromnetz Berlin urged residents whose electricity had returned to reduce consumption to help stabilize the network and allow technicians to reconnect additional households.
Cable repair work is scheduled for Wednesday after overnight excavation, but full restoration may not be possible until Thursday, the operator added.
The blackout also disrupted emergency services in some areas, temporarily rendering police and fire emergency numbers 110 and 112 unreachable.
Numerous schools in the affected area were closed on Wednesday.
