Phuket City Police were informed of the fire, in front of Pink Mansion residential building on Hongyok Uthit Rd, at about 12:05am.
Officers and firefighters from Wichit Municipality arrived at the scene to find the power cables in front of the building ablaze.
The flames had spread to the Italian restaurant Salute, which occupies the ground floor.
The firefighters soon extinguished the flames and confirmed that no people were injured or killed in the fire.
A witness to the fire told police that the fire started from the electricity transformer located in front of the building.
However, police said that officers were continuing their investigation into the fire.