US Energy Secretary Spencer Abraham has promised a thorough investigation into last week's worst ever power failure in North America, ahead of the first meeting of the joint US-Canadian task force.
Blackouts threw New York into chaos
"Like me, President Bush recognises that we owe the nation a full investigation and determination of what happened," Mr Abraham told a news conference in Columbus, Ohio.
The meeting of the joint panel - to be co-chaired by Mr Abraham and Canada's Minister for Natural Resources Herb Dhaliwal - was due to begin later on Wednesday in Detroit.
About 50 million people in eight north-eastern US states and the Canadian province of Ontario suffered the massive blackout on Thursday, which took down several regional power grids.
The exact cause of the failure is yet to be established, but regional power firms have said they are checking their records of conversations with Ohio-based FirstEnergy about problems in the hours ahead of the blackout.
A series of failures in four transmission lines - three of them owned by FirstEnergy - have come under suspicion as the power failure's possible starting point.
However, the company is adamant that it should not be blamed for the outages.
The joint task force is expected to sketch out how to proceed with the inquiry of the massive blackout that shut down parts of the cross-border grid within three minutes.
Some Toronto shop owners kept an overnight vigil at their stores
Experts will examine computer logs detailing the failures preceding the power loss when the panel takes over several separate investigations already under way.
Mr Abraham promised to "investigate why the blackout occurred, how it spread to such a large area and... to make sure such an event never happens again".
Officials have said that an interim report could be ready by mid-September, although a final report may be released several months later.
Some experts have already said that the task force may not find a single event the triggered the cascade of power shutdowns.
The meeting in Detroit comes as US and Canadian cities have been continuing their efforts to restore services, amid fears that a new surge in demand could strain the power grid.
In Canada, experts have warned of possible new blackouts, as surging temperatures - above 30C - were set to test the capacity of a power network.
Earlier, the premier of Ontario, Ernie Eves, has appealed to people to cut electricity consumption in half until electricity supplies were stable.
"I really would like to reinforce the conservation message," Mr Eves told reporters.