The U.S. Court of Appeals ruled yesterday that a federal judge improperly resentenced Potomac lawyer Carl P. Fogel when he added a three-to-nine-year prison term to his one-year's detention on house arrest. Fogel pleaded guilty to receiving stolen goods in the operation of the largest gold and silver fencing operation ever uncovered in Washington.

The decision was written by Circuit Judge Robert H. Bork, who has been nominated by President Reagan to the Supreme Court. He was joined by Chief Judge Patricia M. Wald and Judge Abner J. Mikva, with whom Bork often disagrees.

"We agree that the resentence violated the double jeopardy clause" of the Constititon," Bork said.

The case was remanded to U.S. District Judge John H. Pratt with instruction to correct the sentence. The decision means that Fogel, who completed his year's house arrest on Sept. 2, will not face additional imprisonment.

The judge had imposed a three-year probation period, in addition to the three-to-nine-year sentence, which he had suspended. Under that sentence, Fogel could have been ordered to serve the so-called "back-up" time of three to nine years if he had violated probation.