What are the primary criteria for selecting the size of electric cable in an aircraft?

The primary criteria for selecting the size of electric cable in an aircraft focus on ensuring that the cable can safely carry the electrical load without overheating while also maintaining effective performance throughout the system. Current-carrying capacity is crucial because it determines how much current the cable can handle without exceeding its temperature ratings, which could lead to insulation failure or fire hazards. Allowable voltage drop is also vital, as excessive voltage drop can result in insufficient voltage at the load, which can impair the performance of electrical devices or systems.

Designing aircraft electrical systems requires careful consideration of these criteria to ensure safety, reliability, and efficiency. While other options provided relate to important aspects of wiring (such as voltage and amperage, system voltage and cable length, and physical size and weight), they do not encompass the comprehensive evaluation of both current-handling capability and acceptable voltage drop, which are essential in ensuring optimal system performance and safety in aircraft operations.