A technical fault has caused a Tenaga Nasional Bhd (TNB) transformer at the Bandar Baru Bangi substation to explode Thursday night, said TNB chief executive officer Datuk Seri Che Khalib Mohamad Noh. He said there was interference affecting the operation of the transformer, but power supply was restored to several nearby housing areas an hour later. \"The transformer is currently being repaired, however, residents of surrounding areas have access to electricity,\" he told reporters after launching the state-level TNB Baiti Jannati project here. The explosion and a small fire were reported at 9.20pm causing a blackout in several neighbourhoods.