Fearful of a blackout not unlike one that marred a nationally televised San Francisco 49ers game in late 2011, officials from Entergy and the Superdome embarked on a last-minute, multimillion dollar effort to ensure such a spectacle wouldn't be repeated at this year's Super Bowl.

But the 11th-hour upgrades to the Dome's electrical system, intended to bolster the stadium's electrical reliability, may have contributed to the 34-minute power outage that left New Orleans feeling a bit sheepish in the afterglow of the big game.

In December, a little more than a month before the Super Bowl, Entergy New Orleans was in the process of completing a $4.2 million upgrade to the stadium's electrical system, changing it from "redundant" to "tertiary" — meaning the stadium would now be served by three feeder lines rather than two. With that new equipment coming online, Superdome officials tested their own power lines and found the equipment had "some decay and had a chance of failure."

An engineer hired by the Louisiana Stadium and Exposition District, the public agency that owns the Dome, warned that the stadium's main power feed was "not sufficiently reliable to support the high-profile event schedule."

"Failure of this system will result in loss of events and extreme financial liability to the State, LSED and SMG," which manages the Superdome, David Stelly of the Lafayette engineering firm Associated Design Group said in a report.

The Dome's overseers quickly authorized a rash of repairs.