ROCKLAND — Fire damaged a vacant house Wednesday morning on Camden Street. Acting Fire Chief Raymond Wooster said that the cause of the fire might have been from an electrical source. A state fire marshal and state electrical inspector were at the scene viewing the damage.

Wooster said a determination of whether the fire started from an electrical source should be known by Thursday. The point of origin of the fire was in a first-floor ceiling where wires were dangling, he said.

The Fire Department responded to the fire at 5:16 a.m. to find smoke and flames showing.

The house, owned by Harold Wiley Jr., who resides across the street, had been undergoing renovation. The entire first floor was gutted. The fire spread to the second floor, forcing firefighters to vent the roof so that it could be attacked from the interior, Wooster said.

The chief estimated that 15 or 20 percent of the structure was damaged. Because much of the interior had been removed, damage was minimal, he said. The fire damage would not be a major factor in completing the renovation project, Wooster estimated.

The city had the structure valued at $10,000, Wooster reported.