Sturgeon Bay Submarine Cable Replacement Project now complete
ATC’s three-year project to replace a half-mile, 69,000-volt submarine transmission line under the Sturgeon Bay Ship Channel is now complete. The new transmission line that connects Wisconsin’s lower and upper Door County enhances regional electric reliability and replaces a single circuit with three cables that were originally installed under the channel in the early 1980s.
To install the new circuit, ATC’s construction partner conducted horizontal directional drilling to bore an 1,883-foot-long, 3-foot-diameter hole into the rock bed, 155 feet below the channel. We then connected sections of the half-mile pipe that would contain the cable on land before pulling them through the bore hole under the channel. This required closing three different roadways in downtown Sturgeon Bay for several months, while the duct installation was connected to the termination points. The transmission cables were then pulled through the pipes and completed the splices and terminations.
The ATC project team worked closely with the city of Sturgeon Bay on road, intersection, and parking lot closures, all of which took place on both sides of the channel in downtown Sturgeon Bay. Adding to the challenge was that the city’s concurrent construction efforts to redevelop the west waterfront area in the same vicinity.
“We appreciated ATC’s efforts to include the city of Sturgeon Bay in the route and construction coordination,” Marty Olejniczak, community development director for Sturgeon Bay. “Both sides of the underground bay crossing were tight sites with a lot of activity going on. The high degree of coordination allowed the city’s waterfront construction activities to co-exist with ATC’s crews and enable all projects to move forward smoothly.”
The $14.2 million project also included installing a new riser structure on the west side of the channel and terminations at the First Avenue Substation, along with fiber optic wire at the control house.
“By placing more of the transmission line underground, it allowed the removal of the poles, riser structure and fencing within Sawyer Park and other new development sites being created in the waterfront area, thereby making it more attractive and useable,” said Olejniczak.