The ambient air temperature considered in relation to a conductor ampacity is the temperature of the surrounding air.

• A. True
• B. False
• C. Unknown
• D. Partial

Answer: (A)

Ampacity measures how much current a conductor can carry continuously without overheating, and it depends on how heat is removed to the surrounding environment. The ambient air temperature is exactly the temperature of the surrounding air, and it’s this temperature used in ampacity calculations. When the surrounding air is hotter, heat dissipation is less effective, so the allowable current is reduced. Standard ampacity tables use a reference ambient temperature (often 30°C) and apply correction factors for higher ambient temperatures. So the statement is true: the ambient temperature considered is the temperature of the surrounding air.