HEPCO (Hydro-Electric Power Commission of Ontario), now part of Hydro-One.

This pole is part of a heavy-duty "wishbone" line that goes for several miles and besides most of the insulators being replacements, remains mostly unmolested for the most part. This line might've been rebuilt at least once or so. There's another "wishbone" line w/o the underbuild that runs parallel across the road.

69kV for the transmission overbuild. The underbuild seems around 7,200V. Converted to Y at some point from assumed Δ. Note the glass pin-top on the left wire (converted to neutral).

src: G00gle Maps