Fire Investigators Focus on Power Lines : Sylmar: Utility companies dispute eyewitness reports of electrical arcing near transmission towers before the blaze.

Witnesses told investigators that they saw sparks falling from power lines on a Sylmar-area hillside before a fire erupted Monday that burned 750 acres of brush and damaged several ranch buildings.

But utility companies disputed that view Tuesday, saying their equipment did not malfunction until after the fire started.

Los Angeles fire officials said the cause of the blaze remains under investigation, but electrical arcing from a power line or transmission tower emerged as a focal point of the inquiry.

Fire Capt. Steve Ruda said the fire originated on a desolate ridge above Grapevine Canyon in an unincorporated area traversed by huge transmission towers. Those towers carry numerous high-voltage lines through the Newhall Pass.

Ruda said fire investigators were told by witnesses that they saw sparks falling to the ground before the fire was reported about 12:20 a.m. Monday. Winds were gusting up to 40 m.p.h at the time and could have damaged lines or tower equipment, causing a shower of sparks to fall on parched brush below, he said.

“They said it looked like fireworks coming down,” Ruda said.

The unidentified witnesses, however, saw the arcing from varying distances in the area and fire officials have not pinpointed the exact location on the ridgeline where the fire started or located the equipment that might have malfunctioned.

Southern California Edison and the Los Angeles Department of Water and Power have high-voltage lines in the area and share some transmission towers. But officials for both utility companies said they have no indications that their equipment caused the fire.

Edison spokesman Paul Klein said none of the company’s lines in the area were energized Monday morning, meaning they were not being used to carry electrical current. He said several utility poles owned by the company were destroyed in the blaze.

DWP spokeswoman Lucia Alverlais said 11 DWP power lines in the area had malfunctions in the power relay Monday morning but that such arcing, or flashover, did not begin until after the fire was reported, and probably was caused by the effects of the fire’s heat and smoke on the lines.

“The first indication we have that lines were not relaying was at 12:43,” Alverlais said. “We don’t have anything that substantiates” electrical malfunction as a cause of the fire.

Ruda said seven investigators from the city, county and U.S. Forest Service fire departments are probing the cause of the blaze. He said they have not ruled out any possible causes, including arson.

Fire officials said the blaze moved through Grapevine Canyon and then turned east, skirting expensive homes on Saddle Ranch Road and threatening a 600-unit mobile home park. Hundreds of residents evacuated their homes as the fire approached. The blaze left three firefighters with minor injuries and destroyed structures on two ranches, where hired hands lived.

The fire was totally contained by 10 p.m. Monday, nearly 22 hours after it began. Patrols of firefighters, however, stayed in the burn area throughout the night and Tuesday to watch for flare-ups. It was declared extinguished at 4 p.m. Tuesday.

“We will keep units standing by,” Ruda said. “It is a matter of rooting out minor hot spots.”