An underground transformer exploded Tuesday closing a Norwalk street, officials say.

The incident happened on North Main Street just after 9:30 a.m.

Firefighters arrived to find heavy smoke coming out of an electrical vault.

 

Officials say the explosion was so powerful that it blew the doors open on the vault.

Fire officials contacted the electric company to shut down the power so they could fight the blaze safely.

"We have a series of checks that we do, with the electric company, and they confirm, and then we go to their supervisors and they confirm and then we pass it back down to our firefighters and allow them to put water in the vault, yes. We're very cautious about that and do it in a secure fashion," Norwalk Deputy Chief Edward Presctt says.

South Norwalk Electric and Water says it has restored power to a majority of customers in downtown South Norwalk who may have been affected by the incident.
Some customers will remain without power while crews work to temporarily replace the damaged transformer.