The union representing the workers says the university refuses to negotiate certain pay scales and raised health care premiums during bargaining.

For the second time in just a little over a month, tens of thousands of University of California workers represented by a pair of unions went on strike Tuesday amid continuing contract negotiations.

Citing what they say are unfair labor practices, union workers plan to stage a one-day strike Tuesday at University of California medical and academic campuses statewide, including UC San Diego. UC San Diego Health said Monday that it expects little impact to patients from the strike with all facilities expected to remain “open and operational.