A fire in Boston’s Back Bay on Tuesday night left some 12,000 without power on Wednesday as the city struggled to return to normal. A fire in a 115,000-volt transformer was reported around 6:30 p.m. in the residential neighborhood Back Bay, sending black smoke through the streets of Boston. Local power company NStar then shutdown power to avoid the spread of the fire. An estimated 800 NStar workers are currently working on restoring power to the estimated thousands who were left stranded. Around 11,000 people were still without power by noon on Wednesday, with parts of the Theatre District, Back Bay and Chinatown already restored.