The outage started at 8:30 a.m. and is expected to last for up to eight hours.
The areas affected include, numbers 162 to 223 Curling Street, Byrne's Avenue, O'Rourke's Avenue and numbers 1 and 2 Leggo's Avenue.
In conjuction with the repairs, Curling Street will be closed to traffic from the intersection of the Lewin Parkway to the intersection of Sheppard's Avenue.