DO-160G and MIL-STD-461G contain requirements related to upset and damage immunity to cable induced lightning transients. The ability to quickly predict the risk of damage and/or upset early in the equipment and system development cycles is instrumental in guiding circuit and cable/connector assembly design to ensure economic and first time technical success during equipment qualification and system certification testing. This paper presents methods to predict damage and upset using circuit simulator based methods in situations ranging from simple to complex cable cross-section geometries that are common in defense/aerospace equipment qualification and certification test setups. Test data verifying the simulation process and capability is presented for situations where current waveforms are applicable. Additionally, practical aspects associated with lightning transient generators and how to account for them in simulation and analysis is presented as well.