A police note on Twitter said that firefighters had been alerted at 0545 GMT and had put out the fire, which also affected some 2,000 commercial entities, while mobile phone services and landlines might also be impaired, Reuters reported.
Criminal investigators were on the scene to assess the cause of several cables having caught fire, it said.
Police and emergency services were at the scene to handle the incident and respond to citizens' enquiries, it said, as the German capital endured freezing temperatures.