Bridge-Supported High-Voltage Cables

Location: Cape Hatteras, N.C.

Client: Cape Hatteras Electric Membership Corp.

Burns & McDonnell worked with Cape Hatteras Electric Membership Corporation to install one of the longest bridge-supported high-voltage cables in North America. Daily power outages in the resort area of Cape Hatteras Island required an upgrade of the 34-kV system to 115-kV before the busy summer tourist season. Burns & McDonnell engineers worked with the North Carolina Department of Transportation, Brugg Cable and area permitting agencies to design and install approximately 3 miles of single circuit 500 kcmil XLPE 115-kV cable in fiberglass ducts.

The substation that Burns & McDonnell designed for this resort area had to include design provisions for high winds and rain associated with hurricanes. The design included civil and structural design of a nearly three-mile long cable attachment to the Bonner Bridge that connects the cape to the mainland.

Other challenges faced by Burns & McDonnell included preserving wildlife refuges and national parklands, and the threat of hurricanes. Since activation in 1995, Cape Hatteras has not experienced a power outage. Burns & McDonnell won a Kansas Consulting Engineers Council Award for the Cape Hatteras Island Oregon Inlet Bridge Cable Project.