NEW ORLEANS — The company that supplied electricity to the Super Bowl says the blackout that halted the big game was caused by a device it installed specially to prevent a power failure.

But the utility stopped short of taking all the blame and said Friday that it was looking into whether the electrical relay at fault had a design flaw or a manufacturing defect.

The relay had been installed as part of a project begun in 2011 to upgrade the electrical system serving the Superdome in anticipation of the championship game. The equipment was supposed to guard against problems in the cable that links the power grid with lines that go into the stadium.

“The purpose of it was to provide a newer, more advanced type of protection for the Superdome,” Dennis Dawsey, an executive with Entergy Corp., told members of the City Council. Entergy is the parent company of Entergy New Orleans, the city’s main electric utility.

Entergy officials said the relay functioned with no problems during January’s Sugar Bowl and other earlier events. It has been removed and will be replaced.

All systems at the Superdome are now working, and the stadium was to host a major Mardi Gras event tonight, said Doug Thornton, an executive with SMG, the company that manages the stadium for the state.

Panthers

Charlotte’s City Council is backing a plan to give the Carolina Panthers nearly $144 million from a food and beverage tax hike to pay for upgrades to its downtown stadium.

The tentative deal announced Friday by Charlotte Mayor Anthony Foxx would require approval from the N.C. General Assembly for the city to increase its prepared food and beverage tax by one cent.

That part of the deal hasn’t been settled. The money would be paid over 15 years and requires the team to stay in Charlotte for that period of time.

Eagles

Philadelphia completed new coach Chip Kelly’s staff on Friday, adding Dave Fipp as special teams coordinator.

Fipp, 38, was the assistant special teams coach for Miami from 2011-12.