Explosions Jar Electrical Vaults

In unrelated incidents Tuesday, a half-ton concrete-and-steel utility vault cover was blown open and a second dislodged by electrical line explosions, officials said.

The first incident, on Mira Loma Avenue in Anaheim, apparently happened when pressure from a power surge pushed off a cover that is part of the roadway and sits atop a 60,000-volt transformer, Anaheim fire officials said. Power service was not disrupted.

Separately in Irvine, an electrical explosion slightly dislodged another vault cover, authorities said. That incident, near Jamboree Road and Michelson Drive, cut power to about 10 traffic signals through the day, but no businesses or residents lost power.

Nobody was hurt, officials said.

Such explosions are rare in winter but are as common as broken water pipes during summer months, an Irvine Police Department official said. Police and fire officials said they are investigating whether high power demand might have caused the two explosions.

Southern California Edison spokesman Tom Boyd said the incidents are not related to California’s power crisis. “Power consumption now is actually down,” Boyd said. “Sometimes [vaults] just fail.”

Vaults explode “now and again” when equipment fails, such as when a wire, a switch or a transformer malfunctions, Boyd said.

The two incidents Tuesday were unrelated, he said. Edison is responsible for the vault in Irvine but Anaheim’s municipal power department is responsible for the other, Boyd said.