Aurora Energy is investigating a fault that left more than 3000 customers without power on Sunday night in Dunedin.
Aurora Future Network and Operations general manager Matt Settle said a fault response crew was trying to find the cause of a sub-transmission cable fault that connected 3379 customers to its zone substation in Kaikorai Valley.
The power supply for Balaclava, Belleknowes, Bradford, Brockville, Dunedin Central, Glenross, Kaikorai, Kenmure, Maryhill, Mornington, Mount Grand and Roslyn went out about 9pm on Sunday.
It was restored about 10pm for some customers and 10.30pm for the rest.
Mr Settle said specialised equipment had to be used to locate the fault before repairs could be made.
In the meantime, Aurora had reconfigured the network to supply power to customers from alternative feeders from other nearby zone substations.
Aurora typically had two sub-transmission circuits feeding its Kaikorai Valley zone substation, but the other circuit was out of service for maintenance.
"When the fault location is confirmed, our fault response crews will undertake the repairs to return the cable to service as soon as possible.
"It is uncommon for an issue like this to occur, and we apologise to customers who were affected by the power outage."
