The ampacity of conductors is derated when the ambient temperature exceeds ___ºF.

Ampacity refers to the maximum amount of electrical current a conductor or device can carry before sustaining immediate or progressive deterioration. When determining the ampacity of conductors, various factors, including ambient temperature, play a crucial role.

When the ambient temperature exceeds 86ºF, the ampacity of conductors is derated. This derating is necessary because as temperature increases, the electrical resistance in the conductors changes, and they may not be able to safely carry the rated current without overheating. Conductors are often specified by their ampacity at a standard temperature, and exceeding that temperature necessitates reducing the current capacity to prevent potential safety hazards, such as melting insulation and the risk of fires.

This derating requirement helps ensure the safe operation of electrical systems, especially in environments where high temperatures may be prevalent. Therefore, knowing the threshold at which derating occurs is crucial for electricians and engineers to maintain safety standards in electrical installations.