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ZA-1 230kV Underground Transmission Line

A 230 kV underground transmission line project installed throughout the congested city of San Francisco.

ZA-1 230kV Underground Transmission Line

We were selected to provide engineering, procurement and construction services for the Embarcadero-Potrero 230 kV Underground Transmission Line Project. The project includes a new 230 kV XLPE cable transmission line circuit from the new Embarcadero GIS Substation to the new Potrero GIS Substation located throughout the city and county of San Francisco. 


While there were many challenges associated with the project, such as congested urban areas, unknown existing and unmarked utilities, poor soils, high-volume traffic areas, land-to-below-water HDD and large precast vaults, PG&E never lacked confidence in our proficiency and capabilities to take on this project and follow through. 

Our services were phased as follows: 

  • Phase 1: Detailed Engineering – designed underground duct bank, vaults and horizontal directional drills.
  • Phase 2: HDD Installation – installed six horizontal directional drills.
  • Phase 3: Duct Bank Construction – procurement and installation of the underground bank and vault systems.