Hundreds of Wollongong residents were without power for two hours on Sunday morning.
A resident reported hearing a loud bang and seeing purple smoke on Young Street about 8.45pm, a spokeswoman for Endeavour Energy said.
About 1500 customers lost power at the same time.
Endeavour Energy crews quickly restored power to half of the affected homes and businesses and had the remaining 655 back on within two hours of the incident.
More to come