The 34.5kV Dededo Electrical Distribution Line was constructed to supply stand-by electrical service from GPA’s Combustion Turbines 1 & 2 at their Dededo power plant to Andersen Air Force Base during major outages created by typhoons or any other factors resulting in power outages for the Air Force. The project was funded in its entirety by the U.S. Air Force with AMEC, a major construction management firm out of Philadelphia, as the prime contractor. Black Construction was selected as the prime subcontractor on this project due to their experience and reliability in high voltage underground work with specific emphasis on the installation of 34.5kV underground transmission circuits.

The primary scope of the work involved the installation of approximately 85,000 linear feet of six-inch diameter and another 42,240 linear feet of four-inch Schedule 20 PVC conduit buried in the same trench. The alignment of the 34.5kV line underground line begins at the Dededo switch yard where the first primary electric manhole was located. From the CT-2 switch yard, Marine Corps Drive was crossed to the shoulder of the outbound lanes to AAFB, running parallel to Marine Corp Drive. After turning right at the Marbo electric substation road, the alignment then snakes its way through various easement locations until the line reaches Route 15. At this point, the line then parallels Route 15 until it finally reaches the back gate of Andersen AFB. From this point, the line now doubles in quantity of conduits installed due to the installation of not only the 34.5kV circuits, but also the installation of the one-each 13.8 secondary circuit – each having their own manholes. Underground lines are now located and parallel to Santa Rosa Boulevard from the back gate and eventually to the main switch yard within AAFB.