The resulting short circuit at Hydro One’s Manby Transformer station — near Kipling Avenue and Bloor Street West — knocked out the lights for 120,000 customers.
“We have to ensure that a minimum clearance is always maintained, so you don’t have a flash-over effect from the high-voltage line to any object that’s beneath the line,” said Mike Penstone, vice president of transmission planning at Hydro One, the province-wide power transmission company.
A spokeswoman at Toronto Hydro confirmed a wayward pole may have been the problem.
“We need to do some further investigation,” Tanya Bruckmueller told CBC News via email. “We're now jointly investigating the potential of their lines coming in contact with ours.”
At its peak, the blackout covered an area bordered by Yonge Street, Lawrence Avenue, the Mississauga boundary, and Dupont Street according to Hydro One, though neighbourhoods further south and east were also said to have been affected.
The lights were out for roughly two hours for the hardest-hit neighbourhoods, and came back on around 11 p.m.