Fast food workers in several chains planned to walk off the job this morning as part of a national protest calling for higher wages in the $200 billion industry.

The workers at the McDonald's, Wendy's, Burger King and KFC stores are part of what's expected to be a 100-city strike in support of wages of $15 an hour and union representation. The first such strike was one year ago.

Workers in Philadelphia are not expected to join in, though some students at the University of Pennsylvania are expected to hold a solidarity rally.

In Delaware, workers, among other places, plan to walk off the job at the Wendy's on Concord Pike and the McDonalds on W. 4th Street. The state has 11,200 fast-food workers making a median wage of $8.57 an hour, according to information supplied by 32BJ SEIU, a union representing service workers.

However, it's not clear what the actual turnout will be, how many of the participants are workers and what impact they'll have on restaurant operations.

The actions could mark the largest showing yet over the past year. At a time when there's growing national and international attention on economic disparities, labor unions, worker advocacy groups and Democrats are hoping to build public support to raise the federal minimum wage of $7.25, or about $15,000 a year for full-time work.

The Associated Press contributed to this report.