As per API 612, the condensing turbines are required to be equipped with grounding brushes. however doesn't specify the type of driven equipment! as I understand would be applicable only for generator application and not for Mechanical drives. Throw some lights please.
The act of steam condensing on the last stage(s) of a condensing steam turbine generates static electricity--hence, the requirement for a condensing steam turbine to have shaft grounding brushes, regardless of the type of equipment being driven by the condensing steam turbine.