The incident took place around 9:35 a.m., Tuesday, Jan. 21, in front of 44 North Main Street, said Norwalk Deputy Fire Chief Edward Prescott.
According to Prescott, the vault/transformer had its door blown open with flames and heavy black smoke showing, when firefighters arrived on the scene.
Firefighters initially stood by with a hose line and checked the buildings near the vault for any smoke or fire extension, as South Norwalk Electric Works secured power at a substation, Prescott said.
When it was confirmed the power was off, the fire was quickly extinguished. There no damage to the surrounding buildings, although some shops and offices shut down due to no electricity, he added.
A woman who worked in the area was discarding some trash in the container alongside the vault when the explosion happened was uninjured in the blast.
SNEW officials responded quickly to the scene to secure power and once the fire out began work on restoring power to the area.
The buildings in the immediate area that are supplied by the transformer and equipment in the vault, will be out for at least the day, Prescott.
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