The blaze in an underground utility vault on Saturday night did extensive damage to the area's electrical infrastructure, cutting power to roughly 1,900 customers with meters in 112 residential and commercial buildings in the downtown west end.
The area was re-energized at 5 a.m. MT, several hours ahead of the midday timeline officials had set earlier in the week.
Crews with the city’s utility company, Enmax, have been working round the clock to replace about 3.5 kilometres of electrical cable destroyed by the fire.
Residential property managers are being asked not to allow tenants to re-enter until their buildings' systems have been inspected.
The city expects most affected businesses and other buildings, such as the Calgary Courts Centre, will be up and running on Friday.