The accident took place inside the Provincial Electricity Authority (PEA)’s Region 2 office in the northern province’s Muang district.
Construction of the 142-million-baht building began on May 20 and was scheduled to be completed on November 10 next year, Pol Colonel Pakpoom Prabsriphum, superintendent of the Muang district police station, said after inspecting the scene.
Pornpoj Juthakul, a senior engineering specialist at the Samor Khae Tambon Administrative Organisation (TAO), which has jurisdiction over the area, said the construction began before the local authorities had issued a permit.
He added that the TAO had been notified about the construction plan in a letter, but no official documents, building blueprint or application was submitted.