The allowable ampacities listed in the NEC are based on an ambient temperature that does not exceed which temperature?

The allowable ampacities listed in the National Electrical Code (NEC) are based on an ambient temperature that does not exceed 86 degrees Fahrenheit. This temperature is important because electrical conductors and equipment are rated for specific temperatures to ensure safe and efficient operation. If the ambient temperature exceeds this limit, it can lead to overheating, which increases the risk of insulation damage, decreased performance, and potential fire hazards.

Thus, the NEC standards assume that the electrical equipment will operate within this temperature range to ensure the reliability and safety of electrical systems. This standardization helps in providing a clear guideline for installations, ensuring that electrical systems can handle the load without exceeding the thermal limits of the materials.