About 800 homes and businesses lost power as the fire, east of Perth Airport in Western Australia, approached properties near Maida Vale, Forrestfield, and Kalamunda.
Arson investigators charged a 19-year-old man with breach of duty after he allegedly threw a firecracker into dry grass just after midnight, igniting the blaze.
The emergency escalated on Thursday as temperatures rose and the fire threatened homes and property, before Emergency WA downgraded its warning to a watch-and-act alert.
An evacuation centre was opened at High Wycombe Community and Recreation Centre, with residents on alert, with fire conditions constantly changing.
More than 160 firefighters worked through the night to contain the blaze as it tracked westward, destroying more than 25 hectares of native bushland.
"We have got a fire break all the way around the fire, but there is still a significant risk to the community," Incident Controller Paul Postma said.
"We've had power lines burnt. We've had trees burned.
"It's still not controlled, we have the fire inside a box - contained within mineral earth brakes put in by dozers and front-end loaders, and it's going to take us a number of hours to make sure that we get the fire controlled."
Several structures, including fences and a shed were thought destroyed but no homes were reported lost in the fire, as authorities urged residents to remain vigilant.
The teenager charged over the incident was expected to front the Perth Magistrates Court on Thursday.
