A fire at a 40-unit apartment building on Gauvin Road in Dieppe started in the attic of the north end of the building.
District Chief Marc Cormier says investigators have determined the fire was not caused by a human act.
Cormier says the apartments and balconies below the fire were ruled out as possible sources.
The electrical system did sustain severe fire-related damage.
But he adds the exact point of origin remains unknown and is still under investigation.
More than 50 tenants were displaced from their homes over the weekend and the Red Cross had been helping many of them.
