Groundbreaking Underground Electric Transmission Line Installed in California

Burns & McDonnell has completed construction of Southern California Edison’s Mira Loma-Vincent 500kV Underground Transmission Project in Chino and Chino Hills, California.  

The project was one of the world’s first 500kV transmission lines ever installed underground and is the final link in Southern California Edison’s effort to deliver electricity from new wind farms in Central California to the Los Angeles Basin.

“The successful completion of this project has allowed us to continue delivering safe, reliable, renewable energy to our customer base of more than 15 million,” says Roman Vazquez, senior project manager at Southern California Edison. “Burns & McDonnell delivered a cost-effective solution, on time and under budget — we couldn’t be happier with the results and their overall support.”

The project won an Honor Award in the American Council of Engineering Companies of California’s (ACEC California) Engineering Excellence Awards competition. The high-profile award contest recognizes the best engineering and construction projects in Californiain a number of different categories. The project was also honored with an ACEC National Recognition Award.

“We’re proud our work with Southern California Edison is being recognized among some of the most innovative and creative engineering solutions in our industry,” said Travis McKinney, Burns & McDonnell Construction/Design-Build department manager in Southern California. “Our focus is always on making our clients successful and producing sustainable solutions to support our communities. Facing many unique regulatory, civic, design and construction challenges, our team was able to come up with a first-of-its-kind solution so our client could expand renewable energy and enhance regional power grid reliability.”

The 3.7-mile, 500kV underground transmission project crossed two major thoroughfares, several minor roadways, a shopping center, two flood-control channels and two holes of a golf course. One-third of the alignment was on a 15 percent average grade, with slopes as steep as 35 percent in some locations. In all, the project involved the installation of approximately 17,000 linear feet of duct bank and numerous horizontal drills ranging from 800 to 2,100 feet in length.