An apartment with 18 houses is situated on Thomas Street in Kadaperi near Tambaram. A transformer was erected inside the apartment by the electricity board to provide a better power supply.

On Monday morning, the transformer blasted and the bikes and a car which were parked near it caught fire. Police said at the same time an AC outdoor unit also blasted in a house in the apartment.

The residents rushed outside the house in fear and the Tambaram fire and rescue team who visited the spot doused the fire. The Tambaram police have registered a case and further inquiry is on.