MIAMI -- A relatively minor glitch in Florida's electrical grid somehow triggered a chain reaction Tuesday that caused a nuclear plant to shut down and briefly cut power in patches from Daytona Beach through the Florida Keys.
Up to 3 million people -- about a fifth of Florida's population -- lost power at various points during the afternoon, though there were no safety concerns at the nuclear plant. And while many areas were hit hard, the outages were short lived and only about 20,000 people lacked electricity during the evening commute home. Most of the evening outages were due to bad weather, not the grid problem, officials said.
An equipment malfunction in a substation near Miami disabled two power distribution lines between Miami and Daytona Beach, and in response, Florida Power & Light's Turkey Point nuclear plant south of Miami stopped operating around 1 p.m., Nuclear Regulatory Commission spokesman Kenneth Clark said.
The utility was trying to determine what caused equipment failure and a fire at the substation, but the company said it was not the kind of problem that should have created the widespread blackouts.
Grid problems caused both Turkey Point reactors to shut down, said the utility's nuclear spokesman, Dick Winn.
"All the safety systems worked just like they were supposed to and both of those units are in stable condition right now," he said. Clark agreed the plant's safety was not in question.
The outages had no connection to terrorism, Homeland Security Department spokeswoman Laura Keehner said. Miami-Dade County Mayor Carlos Alvarez said the outages were technical, not criminal.
"It's a matter of just a cascading effect," he said.
Florida emergency management officials said the outages cut power to 2 to 3 million people during the heat of a day that saw temperatures reach the 80s.
The federal nuclear commission said based on reports from its resident inspectors at the plant, the initial drop in voltage came from outside Turkey Point, but the problem worsened when the two reactors shut down, the panel said.
The Federal Energy Regulatory Commission, which has responsibility for electricity grid reliability, said it wants to know whether there were any violations of federal grid reliability rules.
The sporadic outages spanned 300 miles of the peninsula but appeared to be concentrated in the southeast portion of the state, including Miami. Communities along the southwest coast, in the Florida Keys and as far north as Daytona Beach reported interruptions.
Miami International Airport, the Port of Miami and the area's rail and bus transportation were working normally, although some places briefly relied on generator power, officials said.
Several Miami-area hospitals switched to backup generators when the power went out. Miami-Dade schools were scheduled to be dismissed on time, and officials said school buses were running.
By 2 p.m., most of northern downtown Miami appeared to be back to normal operation, including a campus of Miami Dade College and numerous stores and businesses. In the Florida Keys, spokesman Andy Newman said areas were without power for about 30 minutes.
At a Starbucks in Miami's western suburb of Doral, employees began handing out sandwiches they feared would go bad.
Nelson Suarez, 35, a manager for Asia sales at World Fuel Services, enjoyed the free lunch.
"I can't work anyway since all the power is out, so at least something good came out of this," he said.