The Academy on Charles off-campus housing for Johns Hopkins University called Clinton Electric to check power to the elevator. Called onsite to troubleshoot as a possible electrical issue. Checked voltage at the unit disconnect and found to be correct. Opened the panel feeding the elevator and heard a loud buzzing. Found and identified a mislabeled breaker was burned on the “A” phase connecting to the “A” bus. Using a spare breaker of the same type, relocated and extended the wires to shunt. Energized the panel and tested. Checked operation of the elevator. All work was tested and completed.