Which factor must be considered when determining the ampacity of conductors installed in a raceway?

When determining the ampacity of conductors installed in a raceway, ambient temperature is a crucial factor to consider. Ampacity refers to the maximum amount of electric current a conductor or device can carry before reaching a specific temperature. The ambient temperature surrounding the conductors affects their ability to dissipate heat. If the ambient temperature is high, it can lead to a lower ampacity rating for the conductors, as they may overheat under heavy current loads.

Standards set by electrical codes outline derating factors for various temperatures to ensure safety and efficiency in electrical installations. Properly accounting for ambient temperature is essential to prevent overheating and potential failures in the electrical system.

Other factors like conduction type, voltage level, and the physical size of the raceway may influence the overall design and performance of an electrical installation, but they do not directly affect the ampacity as significantly as ambient temperature does.