KUALA LUMPUR: Power supply has been fully restored to all affected areas in Klang Valley as of 3.02pm.
Tenaga Nasional Berhad (TNB), in a statement, said power returned to most of the affected areas in stages as early as 20 minutes after the disruption occurred.
"TNB's investigation found the power supply disruption that started at 12.39pm this afternoon was caused by a fault in one of the equipment used in one of the main entrance substations in Yong Peng, Johor.
"This has resulted in a power outage of 2.2 gigawatts (GW), which is a total of 10 per cent of the total supply demand in Peninsular Malaysia.
"We apologise for the inconvenience faced by customers due to the power supply disruption," it said.