The Queen Elizabeth Way was opened after being shut down on Wednesday morning.
At around 4 a.m., a transformer fire hit a hydro pole, causing wires to hang low, said Staff Sergeant Stephanie Jamieson of Halton Regional Police.
The fire also caused some power outages in the area, which affected traffic lights, she said.
The QEW was closed as a safety precaution and no injuries were reported.
OPP announced over Twitter that wires were secured and ramps were opening up around 7:15 a.m.
Agencies/Canadajournal