"We thought it was important to get another party looking at this to make sure we were looking at everything that we need to," Entergy spokesman Chanel Lagarde said.
Tests on the electrical feeders that connect incoming power from utility lines to the stadium showed decay and "a chance of failure," state officials warned in a memo dated Oct. 15. The documents also show that Entergy expressed concern about the reliability of the service before the Super Bowl.
The memo said Entergy and the Superdome's engineering staff "had concerns regarding the reliability of the Dome service from Entergy's connection point to the Dome."
The memo was prepared for the Louisiana Stadium & Exposition District, the state body responsible for the Superdome.
Authorities subsequently authorized spending nearly $1 million on Superdome improvements, including more than $600,000 for upgrading the dome's electrical feeder cable system, work that was done in December.
"As discussed in previous board meetings, this enhancement is necessary to maintain both the Superdome and the New Orleans Arena as top tier facilities, and to ensure that we do not experience any electrical issues during the Super Bowl," said an LSED document dated Dec. 19.
Superdome commission records show a $513,250 contract to replace feeder cables was awarded to Louisiana-based Allstar Electric. Arthur Westbrook, Allstar's project manager for the job, referred all questions to the management company.
A lawyer for the LSED, Larry Roedel, said a preliminary investigation found the replacement work in December did not appear to have caused Sunday's outage.
And meters showed the 76,000-seat stadium was drawing no more electricity than it does during a typical New Orleans Saints game, according to Doug Thornton, vice president for the Superdome's management company, SMG
He also ruled out Beyonce's halftime performance. She brought her own generator.
Officials with the utility and the Superdome were quick to note that an NFL game, the Sugar Bowl and the New Orleans Bowl also were played there in recent weeks.
Both Entergy and SMG said Sunday that an "abnormality" occurred where stadium equipment intersects with an Entergy electric feed, causing a breaker to create the outage. It remained unclear what the abnormality was or why it occurred.