
In this Oct. 10, 2005 file photo, UPS delivery man Chris Carhart of South Boston, wheels packages past a store window featuring clocks at Quincy Market in Boston. Our power supply has been so precise we've set our clocks by it — but time is running out on that idea. A yearlong experiment with the electric grid may make plug-in clocks and devices like coffeemakers run up to 20 minutes fast.
Washington - A yearlong experiment with the nation's electric grid could mess up traffic lights, security systems and some computers - and make plug-in clocks and appliances like programmable coffeemakers run up to 20 minutes fast.
"A lot of people are going to have things break and they're not going to know why," said Demetrios Matsakis, head of the time service department at the U.S. Naval Observatory, one of two official timekeeping agencies in the federal government.
Since 1930, electric clocks have kept time based on the rate of the electrical current that powers them. If the current slips off its usual rate, clocks run a little fast or slow. Power companies now take steps to correct it and keep the frequency of the current - and the time - as precise as possible.
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