( CNN ) -- A day after Sunday 's 35-minute power outage during the Super Bowl game in New Orleans , officials were vowing to fix whatever the cause may have been , but no one was saying just what that was . `` We 're going to work very closely with SMG to get to the root of the problem , '' said Charles Rice , president of Entergy New Orleans Inc. , referring to the company that manages the dome . `` We both made excellent preparations for an event like this , and then the system worked the way it was supposed to work . '' `` We 've spent millions of dollars upgrading our equipment , including our electrical feeders , and we 've never had this issue before , '' said Doug Thornton , an SMG executive who was in NFL control at the time of the incident . The interruption in service occurred in a substation that supplies the stadium with power , he said . A piece of equipment in the substation `` detected some abnormalities and it did what it was supposed to do -- it opened a switch , basically a breaker , which shunted the power that we were receiving from Entergy and de-energized the building . '' He noted that electricians and electrical consultants were on site and pitched in immediately . A fire alarm that was hit prior to halftime appears to have had nothing to do with the outage , nor did the halftime show , Thornton said . The halftime presentation was run on generated power , `` which means it was not on our power grid at all , '' he said . Any electrical issues identified in the probe will be addressed , he promised . `` These are fixable problems , '' he said . `` Obviously , for me , it 's a disappointing moment , but when you 're relying on systems , it 's not a human error , it 's an equipment error . We 'll get to the root cause of it and we 'll find out what it is . It 's very disappointing . '' NFL Executive Vice President Eric Grubman praised the fans for remaining calm . `` They acted with the belief that the game was going to come back on , just as you or I would have acted in their seats , and that 's what you and I did . '' Though the investigation has just begun , `` There is no indication at all that this was caused by the halftime show , absolutely none , '' said NFL Commissioner Roger Goodell , referring to Beyonce 's power-packed performance . `` That is not the case from anything we have at this point . '' The company completed upgrades to the stadium 's electrical equipment on December 21 , but that may have had nothing to do with Sunday night 's problem , said Entergy spokesman Philip Allison . `` Since then , we 've had three major events -- the New Orleans Bowl , the Panthers-Saints game and the Sugar Bowl -- `` with no issues . '' On Monday , CBS aired video shot from inside a stadium control room as the outage occurred . `` All right , we lost lights , '' says a man as the room darkened . Moments later , a man says , `` Frank , we lost the A feed . '' `` What does that mean ? '' he is asked . `` It means that we have to do the bus tie . '' `` What does that mean ? '' `` It means about a 20-minute delay . '' The CEO and director of research for Zpryme , a market intelligence and analysis firm for the utility and smart grid industry , said someone appears to have made a mistake in their estimate of how much energy the building 's electrical infrastructure could handle . `` Someone made that decision not to invest , saying , 'We can handle this , ' '' said Jason Rodriguez . `` Come to find out that their load was just much higher than anticipated . '' He continued , `` You can say it 's the electrical infrastructure but , at the end of the day , there 's a human component to it , a decision that had to be made . '' But Bill Squires , a sports facility consultant , was not persuaded anyone was to blame . `` I would be very reluctant to ever point a finger , knowing what I know now , at an individual ; I just think it was one of those things , '' he said . `` I 've got to believe that those guys do the preventive maintenance . '' Besides , Squires said , the outage was no more than an inconvenience . `` Nobody got hurt ; everybody was safe . '' And James Fama , vice president for energy delivery at the Edison Electric Institute , said the system appears to have worked well , given that the lights came back on and the circuitry was not damaged . `` The bottom line for any utility or any electric planner would be -- protect your equipment so that you can re-energize it . And it appears to be exactly what happened . '' CBS , citing ratings figures from The Nielsen Company , said Sunday 's game between the 49ers and the Ravens reached a total of 164.1 million viewers , making it the most-viewed show in U.S. history . Figures were tallied from 6:32 p.m . ET until 8:41 p.m . ET and from 9:11 p.m. until 10:47 p.m . The average number of viewers was put at 108.4 million , which ranked it third .
` ` These are fixable problems , '' says management exec . ` ` It 's not a human error , it 's an engineering error , '' he adds . Video from inside a control room shows the situation unfolding . ` ` We do n't have a lot of details to share , '' an official voice says .