Arizona Public Service said Monday that a breaker on an electrical line opened, causing a big flash and a brief power outage.
APS officials say an employee came forward last weekend and informed them of the breaker opening that caused no damage to equipment and no power line replacement.
The ball of light that looked like an explosion was captured by a traffic camera on Interstate 17 around 4:45 a.m. last Thursday.
It happened to be broadcast by KSAZ-TV when the station showed footage of the roadway during a report on the morning's commute.
But until now, nobody could identify the flash's source.
