THE EE WAS ASSISTING OFFICE PERSONNEL MOVE SOME BOXES USING A DOLLEY WHICH NORMALLY IS NOT INE OF HIS DUTIES. THE DOLLEY THEY WERE USING NEEDED TO BE LIFTED UP PAST A 3"" STEP GOING INTO THE BU ILDING. THE EE REACHED UNDER THE DOLLEY AND TRIED TO LIFT IT UP PAST THE STEP BUT PULLED TOO HARD CAUSING LEFT SHOULDER TO DISLOCATE. PLACED ON RESTRICTED DUTY TWO WEEKS.