(CNN) Bernie Sanders said Tuesday he's not focusing on his upcoming Democratic primary debate this weekend, but instead on backing government workers demanding a $15-an-hour wage.

"We're doing just fine. My debate prep today is to stand with workers who are trying to get a living wage from a contractor with the United States government," Sanders told CNN as he walked back to his Senate office from a rainy rally on the issue at the Capitol. "That's the kind of debate prep that inspires me."

Sanders' appearance standing alongside a few hundred labor protesters in the rain Tuesday morning is only the latest in his history of solidarity with causes deal to labor, including attending a picket line of Verizon workers in Manhattan last month. So far, however, that hasn't yet translated into many union endorsements though he has gotten some.

"We will, we have won major union endorsements, we're gonna win more," Sanders told CNN. "But most importantly it's grassroots, working people that I think we already have. So sometimes you may have a union making an endorsement not necessarily reflective of the grassroots."

Meanwhile, on Saturday, he will be appearing in the second Democratic debate. He was knocked by pundits for giving Hillary Clinton a free pass on her email woes at the first debate.