When decisions from the National Labor Relations Board and an arbitrator conflict, the board’s ruling prevails over the arbitrator’s judgment, a U.S. District Court judge decided in a case last week.In a 25-page opinion, U.S. District Judge John J. Tharp Jr. ruled that an arbitration award can be overruled when it conflicts with a NLRB decision or the arbitrator has exceeded his authority.The case at issue involved a union dispute between the staff at Columbia College Chicago, who are employed as both full-time …