Company begins replacing underwater cables damaged by anchor in Straits of Mackinac

Mackinac Bridge file photo
Posted at 9:42 AM, May 04, 2021

PEWAUKEE, Wis. (AP) — The company whose underwater power cables were damaged by an anchor strike in Michigan's Straits of Mackinac three years ago said Monday it was beginning to install replacements.

A ship anchor in April 2018 struck three of American Transmission Co.'s six cables, which moved electricity between the Lower Peninsula and the Upper Peninsula. Two were severed and another was seriously damaged.

About 600 gallons of insulation fluid leaked into the straits, a channel that connects Lake Huron and Lake Michigan.

The portions of the cables closer to shore were underground, while those in deeper waters where the strike occurred lay on the lake floor.

The company reconfigured the undamaged cables into a single circuit so the flow of electricity could continue. But two operating circuits are needed for reliability, which the $105 million replacement project will provide, the company said.

Finishing removal of the old cables and laying the new ones will take about seven months.

“Together with our contractor partners, we're committed to ensuring this project is completed safely and in an environmentally sensitive matter,” said Tom Finco, a vice president of the company based in Pewaukee, Wisconsin.

The two new cables, moving a combined 138,000 volts, will contain solid insulation with no fluids.