RICHMOND, Va. – Loud booms, blazing fires and acrid, black smoke filled a small area of downtown on Friday. The first calls came in around 11:16 a.m. on Friday, July 24.
Pictures and video of the event surfaced on social media, as concerned folks tried to assess the threat level and cause of the disturbance. Buildings lost power and workers were stuck in elevators.
“Events of this type are rare,” according to spokesperson Janell Hancock with Dominion Power.
Initially officials on scene reported that a blown transformer was the source of three to four explosions, many which were caught on video.
The power was knocked out for businesses along the 500-800 blocks of East Main Street.
“The cause of the cable failure and resulting explosion and fire remains under investigation,” Hancock said. “However, the company suspects the catastrophic failure occurred in a secondary, or lower voltage, cable rather than a transformer or high-voltage line.”
Explosions and fires from failures such as this can occur when the failed cable burns surrounding insulation, which in turn can release gas and ignite because it is in a confined spac, Hancock explained.
“Underground electrical facilities are highly reliable,” she said. “Dominion has a rigorous inspection and maintenance program.”
A Dominion Virginia Power lineman who was transported to a local hospital because of smoke inhalation has been released for full duty.
While Dominion is still investigating what exactly caused the fire, spokesman Rob Richardson said it is possible something “nicked the cable.”
Electrical contractor Greg Green with Davis and Green, Inc. has worked on Dominion’s underground power lines before. “A lot of times this stuff shorts out after being installed for 20 years,” Green said.
Green said the wires are extremely sturdy, but he said it’s very possible for them to get nicked. “A lot of times what we see when these wires go bad is there will be a little bit of a nick in the insulation,” Green said.
Green said water can often seep into the nick and corrode the wire’s insulation.
When the insulation starts to disappear the electrical current is exposed, which can lead to a fire, and ultimately, and explosion. “It could be dangerous if somebody was walking by and this type of short happened,” Green said.
This is not the first time one of Dominion’s underground power lines caused an explosion.
In early July of 2014, a wire near Broad St. and 5th St. failed causing an explosion and several manhole covers to blow off.
Green said there is really nothing that can be done to prevent this from happening. “There’s really no maintenance you do on a conductor, typically the only time it’s replaced is when it fails,” Green said.
Dominion said they inspected the area of today’s explosions last month for any problems, and did not find any issues.
Dominion is still investigating the age of this particular cable that failed Friday.