Widespread power cuts caused by an explosion at an electrical substation caused problems across Victoria on Friday night, amid a record heatwave.
All train services in Melbourne were cancelled and about 500,000 houses and businesses were left without electricity in the city's west, some parts of the CBD and western Victoria.
Full power with back-up services won't be restored until the end of the weekend, when two transmission lines are repaired, although most people affected had power again by midnight.
Earlier on Friday, power was cut to one million houses in Melbourne for an hour at a time.
High temperatures meant power usage soared as people turned up air conditioners, causing transformers and fuses to blow.
Melbourne recorded a top temperature above 43 degrees on Friday. It was the first time since records began in 1855 that the city notched up three consecutive days so hot.
The temperature reached 45.1 degrees in Melbourne at 4.27pm (AEDT).