Southern California Edison's (SCE) mismanagement, and not a malfunctioning power system, was the root cause behind electrical vault explosions and power outages that lasted for a couple of days in July, the company said in a press release Tuesday.

SCE explained that "improper operation and insufficient management oversight of the system" caused the failure of the downtown power network and resulted in the extended outages July 15 and 30. An independent report by Davies Consulting reached the same conclusion.

“We are deeply disappointed that the findings point to shortcomings in SCE’s operation of the network,” said Pete Dietrich, SCE senior vice president for Transmission and Distribution, in the press release.

The company briefed the chief of staff to Long Beach Mayor Robert Garcia Tuesday and posted the statement on its website.

Garcia said the company admitted it was unable to diagnose the problem in the electrical circuits downtown from the start.

"They were not adequately monitoring the network," Garcia said. "There were training issues; there were oversight issues; they had not mapped the network adequately."

The first outage, July 15, started when components called network connectors malfunctioned. They are supposed to keep power flowing to customers, but some were installed wrong, and power flowed back into an underground vault. That caused a bad cable splice to overheat and catch fire. The fire spread via underground conduits to adjoining vaults, causing some of the heavy metal vault covers to explode skyward. Almost 29,000 customers were without power, some as long as five days.

The outage stranded dozens of seniors without power for medical devices, refrigeration, air conditioning or elevator service in their high-rise apartments. It left some 22,000 downtown Long Beach residents without power the first day. About 6,500 were without power for a few days. An apartment house caught fire from candles being burned for light.

A second outage occurred July 30, again launching exploding vault covers, including one that damaged an apartment building. This affected more than 17,000 customers, some as long as three days.

Instagram video of explosion

In the immediate aftermath of the outages, Garcia and other Long Beach city officials criticized Edison for failing to sufficiently inform the city of the progress of repairs.

Although Garcia says the city has looked at the possibility of taking over electrical power provision for Long Beach, Edison has that right under a 60-year franchise agreement that ends in 2030. The Public Utilities Commission, which regulates investor-owned utilities, is conducting its own investigation into the outage.

"As underlying causes of these problems, SCE admits to limited understanding of its own network system prior to the outages, lack of trained staff, out of date circuit maps, lack of processes and protocols to ensure that repairs are promptly completed on the system, and a lack of overall responsibility for the network system by a single entity,” the PUC said in an emailed statement Tuesday.

Edison has paid out $1.8 million in claims from customers and businesses that sustained losses during the power outages.

The city is asking for another $500,000 in compensation for its expenses, including police, fire and city staff who responded to the outage, Garcia said. Edison is negotiating a settlement with Long Beach, but Dietrich declined to say what it was offering.

Assemblyman Anthony Rendon, who represents a portion of Long Beach and chairs the Assembly Utilities and Commerce Committee, called on utilities around the state to focus more on reliability.

"Utilities must take proactive steps to ensure this result, and the Public Utilities Commission must enforce these principles,” he said.

This story has been updated.