Human error cited in Fla. power failure

updated 12:22 p.m. ET March 1, 2008

MIAMI - A power failure that plunged large parts of Florida into the dark earlier this week was caused primarily by human error, the state's largest electric company said Friday.

Florida Power & Light issued a preliminary report saying that a field engineer was to blame for Tuesday's failure, which affected more than 584,000 customers, or the equivalent of more than 1 million people.

The engineer was investigating a malfunctioning switch at one of the power company's substations in west Miami when he disabled two levels of protection for the system, officials said.

While he was making measurements of the switch, a circuit shorted, making a loud noise and smoke that was reported as a fire. Normally, the protection system would have contained the consequences of the short circuit, but because both levels of protection had been removed, the problem cascaded to other parts of the system.

In total, 26 of the company's 435 transmission lines and 38 of its 600 substations were affected. Two nuclear reactors and a natural gas unit at Turkey Point south of Miami shut down protectively. Two other FPL plants were also affected.

"We don't know, still, why that particular employee took it upon himself to disable both sets of relays," FPL president Armando Olivera told reporters.

The employee, who had "significant tenure," has been put on paid leave during an investigation, Olivera said. It would have been appropriate for the employee to disable one, but not two, levels of protection while making measurements, he said.

A full investigation could take months, Olivera said.

More from msnbc.com Racist webcam? TheGrio's test says no View an interactive, HD panorama of N.Y.'s 30 Rock Insider theft a big problem for small charities British music fans celebrate 'anarchy Christmas miracle' Census workers wanted, local roots preferred Answer Desk: Gold may be riskier than it seems Send your holiday pictures to troops

MORE FROM LIFE

Life Section Front

Centenarian voter lauded by Obama dies   Dust storm leads to wrecks in Arizona Decision expected soon in Brazil custody fight Mayor blasts EMTs accused of refusing to help After snow, a race to get gifts, get home Feds impose 3-hour limit on tarmac strandings Nostalgia burns bright for old Christmas lights Mom calls 911 over son's video-game habit D.C. chief slams cop over gun at snowball fight Inquiry into deadly Coast Guard, boat crash Life Section Front   Add Life headlines to your news reader: