About 140,000 households were left without power for over 10 hours in Los Angeles amid a record heat wave in the US city.

Los Angeles: About 140,000 households were left without power for over 10 hours in Los Angeles amid a record heat wave in the US city.

The power outage from Saturday evening to Sunday morning was initiated by an electrical incident at the Los Angeles Department of Water and Power (LADWP) plant in Northridge, reports Xinhua news agency.

According to a LAPWD statement, the 230 kV equipment, which carries high voltage electricity and distributes it to customers in the surrounding area, caught fire and exploded on Saturday evening.

The fire was in an energised storage vault with more than 50,000 gallons of mineral oil, NBCLA reported.

Los Angeles Fire Department Public Service Officer Brian Humphrey said the cause of the fire was accidental and attributed it to a "mechanical malfunction".

The power outage came as much of California baked in heat that broke records.

A record that stood 131 years in Los Angeles was snapped when the temperature spiked at 36.6 degrees Celsius on 8 July.