A failure in the underground power line along Middlefield Road between Loma Verde and Colorado avenues caused 1,958 Palo Alto utilities customers to lose power Tuesday, Aug. 21, according to a city utilities official.
The failure activated the Colorado No. 23 feeder breaker, a protective device that interrupts service when a failure occurs, at 9:18 a.m., Utilities Communication Manager Debra Katz said.
Katz described the Colorado feeder breaker as "very long" and said the outage affected the neighborhoods of Palo Verde, Midtown, Midtown West, Old Palo Alto, Professorville, University Park, University South, parts of the downtown area and the western part of Crescent Park.
Additional customers lost power because crews replacing 60 kilovolt conductor power lines along Alma Street had moved some of the electric load from an Alma feeder breaker to the Colorado No. 23 feeder breaker, Katz said.
Katz said the crews were not responsible for the outage. They were already switching the load back to the Alma feeder breaker when the interruption occurred.
"If anything it expedited the process because we already had a crew out there," she said.
Crews worked throughout the outage to check each major circuit to find the cause of the outage and restored power to the circuits once they verified it was safe to do so, according to the city's website.
They isolated the failed line by noon and restored power to all but 60 customers by 12:20 p.m.
Utilities workers have not yet found the portion of failed line and are still working to replace the 20-year-old cables.