Four fire engines around 25 firefighters were called to a fire at a row of terraced houses on London Road in Thornton Heath.
The ground floor of one terraced house was damaged by fire due to a ruptured gas main. Another two terraced houses were also damaged due to fires involving fuse boxes and a number of other properties on London Road and surrounding roads suffered a power outage.
A cordon was put in place as a precaution and around 70 people were evacuated by police. There were no reports of any injuries.
The Brigade was called at 1815 and the fire was under control by 2007. Fire crews from Norbury, Croydon and West Norwood fire stations were at the scene.
The Brigade's fire investigators believed the fire was accidental and caused by a fault in a neutral supply cable.