The fire began at 5:49 a.m. in the 1600 block of Harrison Street.
When firefighters arrived, they saw flames shooting out of a vacant two story building.
The fire was under control within a few minutes, but rescuers had to call PECO to shut off the power during that time.
37 homes were affected, of which 14 had to be evacuated because they have electric heat.
Power was restored by 10:00 a.m. and everyone was allowed back home.