Originally published September 8, 2011 at 4:24 p.m., updated September 9, 2011 at 7:43 a.m.
SAN DIEGO Power was fully restored to San Diego County after electricity was cut to millions due to human error at a power line switching station in Arizona.
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But despite the restoration, public schools will remain shuttered in San Diego County today, along with federal courts, consistent with announcements made Thursday, when SDG&E reported the outage would likely continue one more day. And the utility asked customers to restrict their electricity usage today because the system remains fragile.
The sudden outage plunged the region into chaos as people were stuck in elevators and traffic signals were out at almost all of the intersections in the county, causing major traffic jams. There were no significant reports of injuries due to the outage and no major reports of disturbances.
The major transmission line supplying power to Southern California went down at about 3:38 p.m., leaving the sprawling region without power.
A worker conducting a procedure at an electric switching plant in Central Arizona - where major electricity transmission lines connect - caused a short circuit triggering the outage, officials said. At one point, the power was out as far north as Orange County, south into Mexico and as far east as Phoenix.
The outage was exacerbated when workers tried to reconnect the transmission line and it failed, officials said.
"This is an event that has not ever occurred in the system before," said Mike Niggli, CEO of San Diego Gas and Electric, at a news conference late Thursday night. "Unfortunately, it happened...in another state."
After that event, the two units at the San Onofre Nuclear Generating Station went offline, which severed the electricity connections from the north. That left the entire SDG&E network without any power, leaving all of San Diego County without electricity.
Operating and protection protocols typically would have isolated the resulting outage to the Yuma area. The reason that did not occur in this case will be the focal point of an investigation now under way.
San Diego police Officer David Stafford said downtown's Gaslamp Quarter was particularly busy Thursday night into early this morning as many residents and tourists flocked to bars to pass the time.
There were several burglaries reported around the city throughout the night, but Stafford said early today it was too soon to tell if the outage was the reason.
Authorities issued a statement advising the public that the county had declared a local emergency, meaning that any looting would be treated as a felony.
City News Service contributed to the information in this report.