[PDF] AN INTRO TO Wiring Harnesses - Aircraft Wire Harness insulation chosen for the aircraft, wire harness design engineer select wire part number to use. Using a 3D CAD system, the wire paths are specified throughout the aircraft. In addition, connector disconnects will determine when a wire goes through a bulkhead. Each wire in a wire segment is then uniquely identified (see Chapter 4 Wire How to identify an aircraft wire or cable | Lectromec How to Identify an Aircraft Wire to Understand Aircraft Wire Degradation. If you would like additional help identifying wires, Lectromec provides both testing and consultation services. You can see an exhaustive list of tests to help you with this process on our Wire and Cable Certification Testing page.