PG&E has released new details of damage to its electrical equipment in the area where Butte County's catastrophic Camp Fire began last month — including a broken power pole "with bullets and bullet holes at the break point."
The new information is included in a letter updating the California Public Utilities Commission on a pair of electrical incidents that occurred Nov. 8 about the same time the fire started and began to race toward the town of Paradise.
One of the incidents occurred at 6:15 a.m. on a major electrical transmission line suspended on a series of high steel towers on a steep slope above the North Fork of the Feather River. PG&E's new letter suggests that a large steel hook connecting high-voltage equipment to a tower near the utility's Poe Dam failed, causing the equipment to arc.
The fire was first reported adjacent to the line, called the Caribou-Palermo 115-kilovolt transmission line, about 15 minutes later.
PG&E's letter also discloses a series of discoveries by utility workers at a site about 2 miles to the west that may have been a second ignition point for the fire. The utility informed the CPUC last month that it had experienced a problem somewhere along a lower-voltage distribution line about 6:45 a.m. Nov. 8, or roughly 15 minutes after the blaze was reported near Poe Dam.
On Nov. 9, PG&E's new letter says, a company employee patrolling the area found a broken power pole along the line that showed evidence of having been hit by gunfire.
The worker "observed that the pole and other equipment was on the ground with bullets and bullet holes at the break point of the pole and on the equipment [that] had fallen to the ground," the letter says.
Three days later, another PG&E worker patrolling the area discovered more damage to the same line: "Wires down and damaged and downed poles at the intersection of Concow Road and Rim Road. ... At this location, the employee observed several snapped trees, with some on top of the downed wires."
The filing comes amid growing scrutiny of the state's power infrastructure and safety and maintenance practices by lawmakers, regulators and a federal judge overseeing PG&E's probation on a felony conviction for violating federal pipeline safety laws.
Cal Fire continues to investigate the cause of the fire, which killed at least 86 people and destroyed almost 14,000 homes in Paradise and the neighboring communities of Concow and Magalia.
Scott McLean, a Cal Fire spokesman reached Wednesday morning, declined to answer whether the new report is part of the agency's investigation or if it is any closer to announcing any findings in the blaze.
"Our investigators continue their work toward determining a cause of the Camp Fire," McLean said.
The PG&E letter includes new details of damage to towers on the Caribou-Palermo 115 kV transmission line. The line "relayed and de-energized" at 6:15 a.m., the letter says. Cal Fire dispatch recordings show someone at the company's Poe Dam called in the first report of the blaze about 6:30. The letter confirms that a PG&E employee made that call.
The letter focuses mostly on damage found on one of steel towers along the Caribou-Palermo line.
The document says that on the afternoon of Nov. 8, an aerial patrol found a "suspension insulator supporting a transposition jumper had separated from an arm on the tower," PG&E's letter said. "The suspension insulator and the transposition jumper remained suspended above the ground."
The following week Cal Fire asked PG&E to help it collect parts from that tower and one next to it that was also damaged, the company's letter says.
"At the time of the collection ... PG&E observed a broken C-hook attached to the separated suspension insulator that had connected the suspension insulator to a tower arm, along with wear at the connection point. In addition, PG&E observed a flash mark on (the tower) near where the transposition jumper was suspended and damage to the transposition jumper and suspension insulator."
In response to emailed questions Wednesday, UC Berkeley electrical engineering researcher Alexandra von Meier explained that suspension insulators support the electrical conductors -- high-voltage cables -- that run between transmission line towers. They prevent the conductors from coming into contact with the tower. Transposition jumpers are devices used to balance the electrical current running through the conductors.
Von Meier, an adjunct professor who is director of electrical grid research at UC Berkeley's California Institute for Energy and Environment, said the broken C-hook suggested a scenario for the fire's start.
"If one of these comes loose, you’d expect that the jumper, which is going to be energized because it’s still connected to the conductor, might swing around and come close enough to the tower to draw an electrical arc, which makes a visible flash. In that case, it would tend to leave behind a flash mark of carbon residue," von Meier said. "This is just like what happens if you stick a screwdriver into a wall outlet -- don’t try this at home! -- and it makes a spark and then leaves a black mark on the wall."
Von Meier said PG&E's report in the letter struck her as "thorough, clinical and factual."
"Without saying as much, it suggests to me a very plausible narrative about where and how the fire might have started," she said.
CPUC spokeswoman Terrie Prosper said Wednesday the new information from PG&E will be incorporated into the commission's staff investigation into the fire.
The regulatory agency is also investigating the company's safety culture.
"A new phase will be opened soon examining the corporate governance, structure, and operation of PG&E, including in light of the recent wildfires, to determine the best path forward for Northern Californians to receive safe electrical and gas service in the future," Prosper said in an email.
In a press release accompanying the report, PG&E issued a statement, repeating its emphasis on safety.
"The loss of life, homes and businesses in the Camp Fire is truly devastating. Our focus continues to be on assessing our infrastructure to further enhance safety, restoring electric and gas service where possible, and helping customers begin to recover and rebuild. Throughout our service area, we are committed to doing everything we can to further reduce the risk of wildfire," the company said.
The new PG&E disclosures came as Butte County authorities announced that the death toll in the blaze had increased to 86.
The sheriff's department said Tuesday evening that Larry Smith, 80, of Paradise, died Nov. 25 at UC Davis Burn Center. The agency said Smith was burned while trying to put out a fire that had engulfed his car.