Human Error Caused Florida Grid Outage

gustep12 writes: An 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. Unexpectedly, 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. Oops. Of course this isn't on the same scale, but disabling multiple levels of safety to run a test also was the cause of the Chernobyl disaster.