In Myrtle Beach, South Carolina, U.S., Santee Cooper is participating in a 20-year program to convert all “entry district” and “beach road district” overhead utilities to underground vaults and enclosures. The electric utility and the city have established a cost-sharing arrangement through their franchise agreement for design, procurement and installation of the underground lines.

A portion of the engineering, which is being done by the city, calls for subsurface enclosures that are hidden from view under sidewalks and streets. In most cases, all utilities are being placed out of sight in subsurface vaults. However, voltage indicators and test points are being mounted in the enclosure near grade level so service technicians can access the equipment without entering the vaults. Large windows in the tank also provide a clear view of the open gap and grounded positions from above ground.

Storm Protection

The 20-year conversion project is being done to lower vulnerability to hurricanes and improve the aesthetics of having utility lines and equipment out of site from tourists who frequent this popular destination. With a history of hurricanes, stakeholders anticipate this solution will better protect the utilities and minimize the time it takes to restore services to merchants and residences. The business community has pushed for the project based on the fact that tourism is Myrtle Beach’s leading revenue generator.

Many of the conversion projects are being coordinated with city-funded streetscape projects. In 2004, a nine-block area along Ocean Boulevard from 9th and 12th Avenues North was completed, which included new streetlighting and water, wastewater and drainage piping. Additional construction is under way to expand the streetscape improvement project to 19th Avenue North, where it will connect with another streetscape improvements targeting 21st Avenue. In most cases, Santee Cooper is working with city crews to install polymer concrete subsurface enclosures manufactured by Stongwell (Lenoir City, Tennessee, U.S.).

Switchgear

To accommodate the underground placement of its circuits, Santee Cooper is installing new switchgear equipment designed and manufactured by S&C Electric Co. (Chicago, Illinois, U.S.). The Vista underground distribution switchgear is rated at 15-kV and includes load-interrupter switches and/or microprocessor-controlled and reset-table arc-spinner or vacuum fault interrupters enclosed in a submersible, SF6-insulated, welded stainless-steel tank.