Did PG&E tower failure spark fire?
Loose transmission line could spray molten metal over foliage, experts say
PULGA >> With winds gusting around 50 mph in the morning hours of Nov. 8, portions of a PG&E steel lattice transmission tower — exposed to the elements high on a ridgetop and originally built when Woodrow Wilson was president — failed.
As high-voltage lines got loose and whipped around, striking the metal tower, molten aluminum and metal sprayed across tinder-dry vegetation, igniting the brush. Arriving firefighters could only watch as the blaze underneath the power lines quickly spread to wild timber and brush.
That’s the horror story about the ignition of the Camp Fire that attorneys, sources and experts have begun to construct after visiting the tower and reviewing records, fire transmissions and other data.
Now a month after the blaze first roared to life along the North Fork of the Feather River, near the resort town of Pulga, sources familiar with a Cal Fire probe say investigators are zeroing in on this “transpositional” tower that helps switch power among transmission lines on the Caribou-Palermo circuit, originally built in 1919. The focus is on whether a tiny O-ring that holds up rows of discshaped insulators, or possibly fatigued steel from one of the tower’s arms, caused the accident.
“It’s there that the likely (O-ring) connection failed,” said Dario de Ghetaldi, an attorney suing PG&E on be-
half of dozens of residents who lost their homes in the Camp Fire. “It could also be corrosion on the support extension. This is high in the mountains, you get very strong winds and they had extreme winds that night.”
PG&E has reported to state regulators that at 6:15 a.m. Nov. 8, a 115,000volt transmission line malfunctioned. About 15 minutes later, fire radio transmissions indicate someone at Poe Dam, a little more than 1,000 feet away from the tower and down a steep canyon wall, reported the fire underneath the power lines amid high winds.
Within hours, the town of Paradise was nearly wiped off the map. At least 85 people died in the fire, and it has destroyed more structures than any other wildfire in this flammable state’s history.
As investigators narrow their focus on the cause, California Public Utilities Commission members next week will revisit policies involving emergency power shutdowns in advance of dangerous fire weather. PG&E had for two days repeatedly warned customers in Butte County it might shut off power the morning of the Camp Fire but decided to keep the power on.
Cal Fire also is investigating a possible second ignition point in the fire, near a PG&E distribution line that failed about half an hour after the Pulga tower malfunction, according to filings with the CPUC.
Numerous lawsuits have been filed against the utility, and its stock price has imploded. CPUC investigators also have begun investigating if PG&E’s equipment and the company’s maintenance of its equipment played a role in the fire, and how it arrived at the decision to keep electrical power on that morning. Simultaneously, a federal judge overseeing PG&E’s probation in the 2010 San Bruno pipeline explosion case is working to determine if the utility committed any crimes that may have caused the Camp Fire.
PG&E repeatedly has said it is cooperating with the investigation, but it could not comment on specifics as the cause of the fire was still being determined.
Shower of metal
On Thursday, a reporter and photographer left Pulga and drove up the winding, dirt Camp Road, namesake of the deadly fire, that snaked underneath the Caribou-Palermo transmission lines before reaching the damaged tower on a ridgeline high above Highway 70. The tower is one of three parallel structures positioned on a steep incline above the road at an elevation of more than 2,100 feet.
Loose wires dangled from the tower, severed after investigators removed various parts as evidence. Private PG&E guards were stationed at three points along the road. The remoteness and rugged terrain around the tower would make any firefight by hand crews nearly impossible.
Catastrophic fire expert Dr. John DeHaan, owner of Fire-Ex Forensics, said an arcing transmission line creates much more danger than your average residential power line atop a wooden pole.
“There’s so much energy there even green vegetation could ignite because it fries the moisture out of anything it hits,” he said. “It chars that, and then the charcoal becomes the conductor.”
DeHaan said he has seen examples where a transmission line hit the ground and transformed the sand into a glassy column, similar to a fulgurite, a form of fused soil created by a lightning strike.
“All of those towers fatigue, and they can get a fatigue crack and with high winds it can start flexing back and forth until it fails,” DeHaan said, describing what would happen when the energized line slapped into the structure or the ground. “That would melt the conductors and generate a shower of molten metal as well as the extremely hot plasma in the arc itself.”
If an O-ring hook or other structure is weakened by metal fatigue and breaks, the insulators are no longer supported and can come in contact with the lines and the tower.
De Ghetaldi said “jumper” cables, which are used to switch currents between transmission lines on the tower, as well as the transmission and distribution lines themselves, should be insulated with rubber coating, similar to a lamp cord. He said the utilities balk at the safety measure because it’s more expensive and adds weight to the lines.
“If the jumper wire had been insulated, the whole thing would’ve been prevented,” he said.
Second start
Catherine Sandoval, a former CPUC commissioner who teaches energy law at Santa Clara University, wrote an article Wednesday recommending 10 regulatory goals to help prevent utilitysparked wildfires. For the six years she served on the commission, ending last year, she warned of safety risks inherent in the maintenance and monitoring of equipment. In an interview Friday, she said she worried PG&E and other companies are “running to failure.”
“Certain conditions can lead to metal corrosion. (Investigators) will look at age and previous exposure to wind,” she said. “Making sure utilities are paying attention to aging infrastructure is absolutely imperative. They should’ve been assessing if there were risks to … the aging towers, particularly since nearby towers suffered wind damage.”
In 2012, a winter storm toppled five towers on the same transmission line. Those crumpled towers were replaced in 2016, but other towers were not, attorneys have alleged.
Sandoval called a failure on a metal transmission line “extremely unusual,” especially compared to more fragile distribution lines on wooden poles.
“Was the cross arm showing signs of stress? Should equipment have been more quickly replaced?” Sandoval asked.
Fire investigators also have retrieved a power pole and other evidence from the location of the second power line malfunction in Concow on the Big Bend 12,000-volt distribution line, about 2 miles west of Pulga. Trees and two wood power poles litter the ground near a single orange construction cone that marks the spot.
In Sandoval’s article, she included photos she took of dangerous power lines. Something must change, she concluded.
“Stemming utilitycaused wildfires is a legal and ethical imperative to protect the safety and health of the people of California,” she wrote, “and the future of our state and planet.”