About 4,500 Baltimore Gas and Electric Co. customers lost power for a half-hour Friday morning after a transformer failed at the company's station on Carroll Street in Westminster.
Customers in the area, which ran east along Route 140 and included much of the city, were switched to other feeder lines until the transformer was repaired, said Peggy Mulloy, BG&E; spokeswoman.
The largest customers in the section that lost power are Carroll County General Hospital, Western Maryland College, Cranberry Mall and the Carroll County Times.
"The system is built so there is enough capacity to transfer customers to other lines," Ms. Mulloy said.
Gil Chamblin, spokeswoman for Carroll County General, said the hospital was unaffected by the power loss because an auxiliary generator "kicks in within 10 seconds after the power goes off." The hospital also has a second transformer, she said.
An automatic generator at the Westminster City Police headquarters also allowed officers to keep working, said Lt. Randy Barnes, a police spokesman.
"The generator powers major parts of the Police Department, which allows us to continue to operate," he said. "We can continue to communicate with the cars on the street."
As of yesterday afternoon, a BG&E; spokesman said he did not know what caused the transformer failure or when it would be repaired.