About 2,000 Justice Department employes received an unexpected, post-holiday paid vacation yesterday when a water pipe burst in the basement of the department building at 10th Street and Pennsylvania Avenue NW, causing a power failure.

A three-inch line to the outside lawn sprinkler system, shut off for the winter, ruptured sometime between midnight and 1 a.m. yesterday, flooding a sub-basement vault where the building's electrical transformers are kept, a Justice Department officials said.

Six inches of water covered the floor of the vault, but General Service Administration workers had pumped it out by midmorning. An emergency generator was supplying power to some areas of the building where a "handful" of employes were working.

"The water has all been pumped out," the official said. "The next question is whether we can dry out all the [electrical] circuits and get them working again."

The spokesman reported that the alternate power was being generated in random spots throughout the building. "For example," he said, "I don't have any lights but the person in the office next door does."

Most of the employes learned of their day off through early morning radio and television broadcasts, but a few who did come to work as scheduled were turned away at the door.

Power is expected to be fully restored by this morning.