During Sunday's game, the relay device triggered, signaling a switch to open when it shouldn't have, causing the partial outage.

WSJ: Super Bowl Outage Traced to Faulty Entergy Gear

In some cases, it can use one mobile device to relay power to another, keeping everything fed even if the main power hub is tied up.

ENGADGET: Sony applies for wireless power patent, wants to daisy-chain your energy

That led the relay, a kind of sensing device, to incorrectly conclude there was an electrical problem and tell a nearby electrical switch to isolate the perceived problem, reducing the flow of power to the Superdome during the game's third quarter.

WSJ: Device Setting Triggered Super Bowl Outage

Entergy told New Orleans City Council members that the company still doesn't know why the device triggered, but the relay has been removed, the dome's electrical system is ready to go and steps will be taken to ensure a malfunction doesn't happen again.

CNN: STORY HIGHLIGHTS

The relay, put online late last year, triggered unexpectedly, causing another device to stop supplying power to part of the building, Entergy New Orleans told city officials Friday.

CNN: STORY HIGHLIGHTS

On Day 44 of the trek, both a radar device meant to measure the ice thickness and a satellite communications unit to relay the data are still not working - despite being brought back to the UK for repairs and then delivered to the team last week.

BBC: Arctic team gives up on ice radar