WASHINGTON, Aug 2 (Reuters) - U.S. Treasury Secretary Janet Yellen on Monday took additional steps to preserve the federal government’s borrowing capacity under a reinstated debt limit, suspending some investments in government employee retirement and health benefits funds. In a letter to House of Representatives Speaker Nancy Pelosi and other congressional leaders, Yellen said she was suspending investments in the Civil Service Retirement and Disability Fund and the Postal Service Retiree Health Benefits Fund that are not immediately required to pay beneficiaries. (Reporting by David Lawder; Editing by Leslie Adler) Our Standards: The Thomson Reuters Trust Principles.