Age, heat may be behind underground electrical vault explosions in LA, engineer says
Heat may be behind electrical vault explosions
Two underground electrical vault incidents in the Los Angeles area have sent flames and concrete into the street in recent weeks. A forensic electrical engineer says aging infrastructure is likely the underlying factor, and extreme heat can make it worse
LOS ANGELES - As Southern California swelters through a heat wave, questions are growing about the underground electrical vaults buried beneath city streets.
Two recent incidents in Los Angeles sent flames or concrete into the road. A forensic engineer who spoke with FOX 11 says age and heat are a dangerous combination for underground electrical equipment.
What we know:
On Monday, Sept. 21, about 2 p.m., flames erupted from beneath the ground at West Westchester Parkway and Loyola Boulevard, near LAX. Video on social media shows the pavement lifting and fire shooting up as a car passes through the intersection.
Then, just before 4 a.m. Monday, a concrete electrical vault on Ventura Boulevard in Studio City was pushed up roughly 6 to 7 inches above the road, after what appears to have been a fire and explosion underneath.
The Los Angeles Police Department (LAPD) says as many as six cars hit the raised vault. One driver told FOX 11 he believes his car is totaled. No injuries were reported.
LAPD and Los Angeles Department of Water and Power (LADWP) crews responded to the scene.
The LADWP confirmed that this incident caused a power outage related to the underground substructure. The utility stated that the damaged electrical equipment was addressed with permanent repairs immediately following the incident and that there are no ongoing work or safety concerns currently in that area.
What they're saying:
Zacharias Macias, a licensed professional engineer and certified fire and explosion investigator with Macias Forensics, reviewed the video from the incident near LAX. He has not examined the vaults involved, but he said the flames suggest gas was involved.
Macias explained that the points where underground cables connect are a common failure point. Over time, heat and repeated heating and cooling can break down the insulation around the wires and release gases into the vault. An electrical arc can then ignite that gas.
"Age is definitely the underlying factor here," Macias said.
He said extreme heat can add to the problem. "When you have high heat in the area, you're going to have much more electrical power consumption," Macias said. "That's going to draw more current in those conductors, and that's going to accelerate any degradation that's already occurring."
Macias said the key question is whether the utility kept up with maintenance and inspections. "An investigation into their maintenance records and how they keep up their infrastructure is kind of the crux here," he said. He added that someone outside the utility should be part of that review.
Macias said these explosions are not common. As long as the utility stays on top of inspections and maintenance, he said there's no reason to panic. His advice for the public: "If you see smoke coming out from underground, or if you hear a popping or a crackling sound, stay away. Call 911."
"There was a power outage on September 21, in the Westchester area that was related to electrical equipment located in an underground substructure. The damaged electrical equipment was addressed with permanent repairs immediately following the incident. There is no ongoing work or safety concerns currently in the area," the LADWP told FOX 11 in a statement.
What we don't know:
The exact cause of either Los Angeles incident has not been officially determined by authorities.
It is also not yet clear whether the driver seen in the social media video passing over the LAX-area explosion was hurt.
The Los Angeles Department of Water and Power has deferred any questions regarding potential injuries from the September 21 incident to the Los Angeles Police Department.
What you can do:
Macias advises the public to remain vigilant around underground utility infrastructure, especially during periods of extreme heat.
"If you see smoke coming out from underground, or if you hear a popping or a crackling sound, stay away. Call 911."
The Source: Information in this report was gathered from official statements provided by the Los Angeles Police Department and the Los Angeles Department of Water and Power, as well as on-scene witness accounts and social media video footage of the incidents. Additional technical context and analysis were provided through a FOX 11 interview with Zacharias Macias, a licensed professional engineer and certified fire and explosion investigator with Macias Forensics.