POLICE believe an electrical fault involving power lines sparked Saturday's fire at Glenormiston.
Detective Sergeant Andy Raven, of the Warrnambool police crime investigation unit, said investigations had been carried out and were now completed.
The fire, on land bordered by Glenormiston Road, Wallaces Lane and Castle Carey Road, started about 3pm Saturday and burnt about 31 hectares of land, an unoccupied house and a hay shed containing hundreds of bales.
Detective Sergeant Raven said a 12-year-old youth had also been cautioned in relation to a fire at Warrnambool's Bromfield Street last week.
The small grass was deliberately lit at Warrnambool’s Bromfield Street on Wednesday afternoon.
Detective Sergeant Raven said the 12-year-old had not been in trouble with police previously and was therefore eligible for a caution.
That caution came after another 12-year-old Warrnambool boy had been charged with seven counts of arson relating to a string of fires in Warrnambool public toilets.