Auckland city councillors will quiz Transpower as to why tens of thousands of homes and businesses lost electricity last week.
About 74,000 customers were blacked out in the eastern suburbs, as well as Newmarket, Onehunga and Manurewa, after problems at the Penrose substation.
Rolling power cuts were also imposed on more than 10,000 customers in St Heliers and Orakei to help manage demand on the network.
Councillor Aaron Bhatnagar says the blackouts were unacceptable, and Transpower chief executive Patrick Strange will appear before a committee on Thursday to explain what happened.
Mr Bhatnagar says the council is after good-quality answers, and the committee meeting will not be a Spanish inquisition.
