The ampacity of a conductor must not be less than what rating?

The ampacity of a conductor refers to the maximum amount of electric current that the conductor can safely carry without exceeding its temperature rating. This means that the conductor's capacity must align with the requirements set by the overcurrent protection devices, such as circuit breakers or fuses, which are designed to prevent excessive current flow that could lead to overheating or potential fire hazards.

Selecting a conductor with an ampacity that is equal to or greater than the rating of the overcurrent device ensures that the conductor can handle the maximum current that may flow through it under normal operating conditions without tripping the device prematurely. This relationship is crucial for the safe operation of electrical systems.

In contrast, the ratings mentioned in other options, such as voltage, resistance, or even the conductor's inherent current rating, do not directly establish the safe carrying capacity of the conductor in relation to overcurrent protection requirements. These factors can influence performance and safety but do not specifically dictate the minimum ampacity standard that must be met to ensure compliance with electrical codes and safety protocols.