An underground electrical explosion caused 15ft flames to shoot up into the air on Newcastle's Quayside.
The blaze, which involved an 11,000 volt electrical cable, happened at just before 10pm on Saturday night.
As a result of the explosion around 500 homes in the NE1 postcode were left without power, Northern Powergrid have confirmed.
Streetlights around the city centre and the Tyne Bridge are also said to have went dark
Firefighters from Byker and Gateshead arrived at the scene at 9.53pm to find the fire had already been extinguished and used a thermal imaging camera to check for hot spots.
The area was also cordoned off to the public while engineers worked to get the power back on.
Electricity was restored to the NE1 area at around 11.30pm.