What is the ampacity for conductors installed open in free air at 30°C?

When considering the ampacity for conductors installed open in free air at 30°C, it's essential to look at the relevant tables in the National Electrical Code (NEC) that specify ampacity ratings based on installation conditions. For conductors laid out in free air, ampacity is influenced by factors such as ambient temperature and conductor size.

In this scenario, the given temperature of 30°C is significant as it falls within a standard range in which conductors typically operate effectively. The tables in the NEC list the ampacity ratings for various types and sizes of conductors based on their installation conditions. For conductors in free air, the ampacity is generally higher than conductors that are enclosed or in conduit due to better heat dissipation.

The selected ampacity of 85 A correlates with a conductor size—such as a certain gauge of copper or aluminum—when installed under these conditions, meaning it safely can handle this level of current without overheating. This rating helps ensure both safety and efficiency in electrical installations.

Other options likely represent higher conductor capabilities, suitable for different conditions or larger conductor sizes, but for the specific situation outlined, 85 A is the appropriate rating based on established code guidelines for open air installations at 30°C. Understanding