NASHVILLE (AP) - The National Labor Relations Board on Wednesday granted the United Auto Workers petition for a union vote for skilled trades workers at the German automaker's lone U.S. plant in Tennessee.

The workers responsible for maintaining and repairing machinery and robots at the Chattanooga facility are now scheduled to hold a two-day vote on representation by the United Auto Workers starting on Dec. 3.

There are about 162 skilled trades workers at the plant, making up about 12 percent of the total blue-collar workforce. Volkswagen had argued that the maintenance workers shouldn't be allowed to negotiate union agreements separately from the remaining 1,200-member production team, and that the union was seeking to carve out a group of workers more likely to vote for the UAW after the union lost an acrimonious election among all hourly employees on a 712-626 vote last year.

Volkswagen also questioned the timing of the effort to hold an election amid the fallout of the diesel emissions cheating scandal that has engulfed the company.

But the UAW argued that the maintenance workers share unique sets of interests, including enhanced electrical and mechanical skills and training requirements, varying shift schedules, and even different uniforms than their colleagues working in assembly, body welding or the paint shop.

Gary Casteel, the secretary-treasurer of the UAW, criticized Volkswagen for trying to block the vote by skilled trades workers.

"Volkswagen's attempt to sidestep U.S. law was a waste of employees' time and energy, and a waste of government resources," Casteel said in a statement. "Looking ahead, our hope is that the company now will recommit to the values that made Volkswagen a great brand - environmental sustainability and true co-determination between management and employees."

"We have no doubt that Volkswagen can make a comeback in the U.S. and around the world, but the company needs to refocus on its core principles," he said.

Volkswagen Chattanooga spokesman Scott Wilson said the company is reviewing the decision and "considering its options."

Groups like the U.S. Chamber of Commerce decry efforts by unions seeking to create smaller collective bargaining units as being the labor equivalent of political gerrymandering, where the most favorable lines are drawn to gain entry into businesses where the total workforce might lean against union representation. But recent NLRB decisions have gone in favor of such "micro units," including by cosmetics and fragrance workers at a Macy's department store in Massachusetts and certified nursing assistants at a nursing home in Alabama.

The UAW has been thwarted for decades in its bid to represent workers at a foreign-owned auto plant in the South. The February 2014 vote at the Volkswagen plant in Chattanooga was seen as the union's best chance because of strong labor influence o n the German automaker's board.

But anti-labor groups and Republican officials raised concerns that a successful union vote could hurt future expansion plans at the plant, imperil a lucrative state incentive package and dissuade other manufacturers and suppliers from investing in the state.

The UAW dismissed those statements as scare tactics, but were unable to stem the tide against the union in the election. Following that crushing loss, the union created Local 42 in Chattanooga to renew efforts to represent all blue-collar workers at the plant.