Which of the following factors affects the ampacity of a conductor?

The correct answer is that all the listed factors—conductor material, insulation type, and installation method—affect the ampacity of a conductor. Each of these elements plays a role in determining how much current a conductor can safely carry without overheating.

The conductor material, such as copper or aluminum, directly influences ampacity due to variations in conductivity. Copper has higher conductivity than aluminum, allowing it to carry more current for the same size conductor.

The type of insulation is also crucial, as different insulation materials can handle various temperature ratings. Insulation that can withstand higher temperatures increases the ampacity, allowing the conductor to operate safely at higher current levels without degrading the insulation.

Installation method refers to how the conductor is placed, whether it is in a conduit, buried underground, or exposed to air. Each method can affect the heat dissipation of the conductor. For instance, conductors bundled together may not dissipate heat as effectively as those installed separately, thus affecting their maximum safe current-carrying capacity.

Together, these factors must be considered to ensure compliance with electrical codes and safety standards. Therefore, all of the choices contribute to the determination of a conductor's ampacity.