Abstract: On March 17, 2020, a Service Technician (Employee #1), with the assistance of a second Service Technician (Employee #2), was assigned to repair a fault on an inverter system that was part of a solar power plant. They replaced an Inverter 2.2 (#6) card on the #4 DU Disconnect Switch of the deenergized system. At 5:30 p.m., the system was energized to check the reading from the inverter card inside the cabinet. They found that the card had a bad reading. The employees then started conducting a job briefing in front of the live open panel box in close proximity to energized parts, to determine the next steps of the troubleshooting. They discussed that the cable connection at the card was possibly not making good contact. They were going to disconnect and test the cable. Employee #1 reached in and inadvertently moved the inverter card that was still unscrewed. The card fell off, touching the ground on the inverter and causing an arc flash. The voltage at the system was 690 Volts AC. Employee #1 was not wearing gloves, eye or face protection. Employee #2 was standing next to him and was wearing eye protection but no gloves or face protection. They were both wearing fire resistant clothing. Employee #1 suffered serious first and second degree burns to his face, left hand, and eyes. He was admitted to the hospital for treatment for about a week. Employee #2 received minor burns to the left hand and face. He was treated without hospitalization.