With state leaders seeking ways to avoid mass power shut-offs in the future, a Southern California utility company alerted regulators that an incident on its electrical equipment may be linked to the damaging Saddleridge Fire burning in Los Angeles County, officials told The Chronicle on Monday.

The cause of the fire has not been determined.

Susan Cox, a Southern California Edison spokeswoman, confirmed that her company made a report Friday to the California Public Utilities Commission.

“Out of an abundance of caution we notified the CPUC on Friday, Oct. 11, that our system was impacted near the reported time of the fire,” Cox said.

The report was similar to one made by Pacific Gas & Electric Co. last year in the days following the Camp Fire in Butte County, the deadliest and most destructive blaze in California history.

State investigators later concluded that PG&E equipment sparked the fire, a finding that put pressure on PG&E to expand its new practice of doing preemptive shut-offs during dangerous weather.

The Saddleridge Fire began Thursday night north of Highway 210 in Sylmar and by Monday morning had burned almost 8,000 acres, destroyed 17 structures and damaged 58 others. Authorities said one man died from a heart attack and three firefighters suffered minor injuries.

The first firefighters to put eyes on the blaze Thursday reported to dispatchers it was “a quarter-acre under the power lines,” according to radio transmissions reviewed by The Chronicle.

On Monday, Los Angeles Fire Department spokesman Nicholas Prange released a statement saying the area of origin had been narrowed by investigators to a 50-foot-by-70-foot rectangle under a high-voltage transmission tower.

“There is no evidence of a homeless encampment in the immediate area,” he said. “Investigators continue to work around the clock in steep terrain, thoroughly examining all aspects of the scene in an attempt to determine a cause.”

Prange added that in addition to firefighters, investigators from SoCal Edison and private insurance companies have been to the site.

Those electrical lines were apparently live, despite preemptive outages in other parts of the state. SoCal Edison has said it did not de-energize any lines in that area despite shutting off power to more than 20,000 customers the day the fire broke out.

The utility had targeted the Sylmar area earlier in the week, saying households and businesses in the community could be among more than 170,000 customers to lose power. However, Sylmar was eventually taken off the targeted list for an unknown reason. It's unclear if the power lines near the fire origin were ever in the utility de-energizing plans.

At about 9 p.m. Thursday, when the fire started one weather station just north of Sylmar in the San Gabriel Mountains recorded 29 mph sustained winds and up to 53 mph gusts. Another station in Newhall Pass to the north recorded a tinder dry 5% humidity.

In the northern part of the state, PG&E cut power last week to more than 700,000 customers as a precautionary move amid forecasts of high winds.

PG&E said its decision was validated after crews found 100 incidents of wind-related damage to power lines in its power shutdown areas, any of which could have started a fire.

“The winds we experienced, like the winds happening in Southern California, were of such a speed that it blew branches and trees into our power lines, bringing about this risk of ignition,” PG&E CEO Bill Johnson said Friday. “Had those lines been energized we’d had the potential for numerous instances of ignition, but thankfully those lines were not energized.”

PG&E took heavy criticism for its handling of its biggest-ever power shutdown, which included a website that crashed due to customers flooding the outage information page.

SoCal Edison’s website also crashed during its outage, prompting it to tell customers on social media, “Our website is experiencing intermittent issues and we apologize for any inconvenience.”

Public Utilities Commission spokeswoman Terrie Prosper said Monday that SoCal Edison’s full report of the incident related to the Saddleridge Fire was confidential and not public at this time.

She said a utility must report electrical incidents that meet certain criteria: they result in a fatality or injury involving electric facilities; they cause damage to property of the utility or others in excess of $50,000; they receive significant media coverage; or they result in an outage affecting at least 10% of the company’s service territory at a single point in time.

Prange said the Saddleridge Fire was 43% contained as of Monday morning. The blaze led to the evacuation of 100,000 residents in the San Fernando Valley.

He said investigators were reviewing evidence, including from SoCal Edison, while looking at burn patterns and talking to witnesses to try to determine what sparked the fire that was fanned by strong Santa Ana winds.

Matthias Gafni is a San Francisco Chronicle staff writer. Email: matthias.gafni@sfchronicle.com Twitter: @mgafni