The ampacity of UF cable is rated based on conductors of ___ degree C.

The correct choice reflects that the ampacity of UF (Underground Feeder) cable is typically rated based on conductors operating at a temperature of 75 degrees Celsius. This rating is crucial for determining how much current the cable can safely carry without overheating, which ensures both the safety and reliability of electrical installations.

Ampacity ratings are defined in accordance with specific temperature ratings because the temperature at which the conductors are rated directly impacts their ability to dissipate heat generated by electrical current. A higher temperature rating may allow for a greater ampacity, but UF cables are generally limited to the 75 degrees Celsius rating in most applications. Understanding this rating helps electrical workers select the appropriate cable size for their projects, ensuring compliance with safe installation practices as outlined in the National Electrical Code (NEC).

In practical terms, this means that when calculating the required ampacity for UF cable installations, electricians will refer to charts that specify the allowable current for conductors based on the 75 degrees Celsius rating, ensuring that installations can handle expected loads under typical conditions while minimizing the risk of overheating.