TABLE B.310.15(B)(2)(3) Ampacities of Multiconductor Cables

[Adnan Hasan]

in this table, for kcmil 600, the ampacity is 354 @60 C⁰ and increase to 459, 513, and 538 @ 75, 85, and 90 C⁰ respectively^{.
My understanding that as the temperature increase the Ampacity decrease but the table show the opposite} :?
^{I appreciate for clarification...thanks}

 

[GoldDigger]

in this table, for kcmil 600, the ampacity is 354 @60 C⁰ and increase to 459, 513, and 538 @ 75, 85, and 90 C⁰ respectively^{.
My understanding that as the temperature increase the Ampacity decrease but the table show the opposite} :?
^{I appreciate for clarification...thanks}

For a bare wire, the resistance (usually) increases as the temperature increases, so the voltage drop for a given current will increase, or the current for a given voltage drop will decrease. But that is not what this table is about.

The ampacity of a wire given in this table is limited by the insulation on the wire. What this table shows is what current load a wire can take and not get any hotter than the column temperature. Clearly the hotter you allow the wire to get, the more current it can carry before reaching that temperature.