MARCH 16, 2015
LYNN, MASSACHUSETTS
Officials said a short circuit in an underground vault
caused a minor explosion and a fire beneath the sidewalk on Union Street
Saturday evening, prompting some evacuations but no injuries.
“It was all contained underground,” Lynn District Fire Chief
Jack Barry said Sunday evening. “We were able to flood the vault with dry
chemical extinguisher and put it out pretty quickly. We were concerned that the
fire could spread in the vault into adjacent buildings.”
Police and firefighters received a report of a disturbance
at 7:07 p.m. Saturday in the area of 180 Union St. (almost opposite Burchstead
Place) and initially heard reports of an explosion causing injuries, Barry
said.
On arrival, firefighters reported finding nobody injured;
but two grates in the sidewalk about 25 feet apart were each spewing smoke.
Barry said that the city buried utilities underground
beneath Union Street and electrical wires can be accessed in periodic vaults
beneath the pavement. Vents at each end of the vault open into the sidewalk,
kind of like a subway grate.
Barry said firefighters evacuated a restaurant and a church
service out of concern that the fire could travel through the vault into the
adjacent buildings. But the fire did not spread, and firefighters left the
scene before 8 p.m.
National Grid Spokeswoman Darlene Masse said that one
utility workers believed the rain from earlier in the evening and day flooded the
vault and caused a connection to short-circuit. Approximately a 15 customers
were without power for an hour while utility workers made repairs.
Manhole explosions
typically increase during the winter, when salt applied to roads to melt ice
can fray cables that lie beneath the city streets. After the insulation is damaged, the cables
then can short when flooded during storm events, causing sparking fires,
smoking incidents, and blasts due to the increased gas pressure inside the
vault.
Several hundred pound manhole
covers can shoot in the air from that pressure built up. Expect a significant increase in
manhole fires due to the amount of salts used to melt the ice/snow this harsh
winter. Already most areas in the
northeast have seen an increase in the number of incidents compared to previous
years.