Properties in Cromford were among 30,000 homes and businesses across Derbyshire to have power cut off after an explosion at an electricity substation.
Traffic lights along the A6 between Cromford and Matlock also stopped working as a result.
Firefighters were called to the explosion at the substation, on the B5056 near Winster, last Wednesday, October 12, at about 1pm. Crews from across the county had the blaze out by 5pm.
Part of the building housing the 33-kilovolt substation collapsed under the force of the blast.
Electricity network Western Power Distribution had restored power to about 20,000 customers by 5pm that day, a spokeswoman for the company said.
It ordered a demolition of the building on Friday.
An investigation into the cause of the blast was launched on the same day, but a spokesperson for Western Power said the cause would not be known for “several days”.