CONCORD -- The city's largest union plans to show up to work Friday to protest a mandated furlough day.

Members of the Teamsters Local 856 plan to gather at 7 a.m. at the city's corporation yard at 1455 Gasoline Alley, off Bisso Lane near Highway 242, to protest the first of 13 scheduled citywide furlough days.

The protest comes amid contentious contract negotiations between the city and union leaders who want the city to end the furlough program. Negotiations have reached impasse and are headed next month for fact-finding hearings.

In a news release issued Thursday, the union said the city "intends to discipline any employee who attempts to provide public services." The union represents 150 employees, including police dispatchers and maintenance workers.

Interim City Manager Valerie Barone on Thursday said the city will respect the workers' right to protest.

"The city has no intention of interfering with the lawful right of employees to peacefully assemble," said Barone.

David DeBolt covers Concord and Clayton. Contact him at 925-943-8048. Follow him at Twitter.com/daviddebolt.