Mike Dolt Enterprises
Mike Dolt Enterprises
User: curious george, Location: Chapel Hill, NC
Asked on: Wednesday, March 30, 2011 at 10:49 am EDT
Answered on: Tuesday, May 14, 2024 at 3:29 am EDT
Question: 2008 NECSection 400.5I have a situation where STOW or STOOW chord is going to be in ambient temperatures exceeding the 86 degree F default.Section 400.5 states " Where cords are used in ambient temperatures exceeding 86 degrees F, the temperature correction factors from Table 310.16 that correspond to the temperature rating of the cord shall be applied to the ampacity from table 400.5(B).How do I find the temperature rating of the cord? Table 310.16 is for conductors, not cords, and the conductors do not correspond to cords.Table 400.4 gives me the insulation type and it uses for cords, but not the temperature rating.Any help would be appreciated.Thanks -
The temperature rating of a cord is not explicitly stated in the NEC. However, it can be inferred from the insulation type. For example, a cord with a THHN insulation has a temperature rating of 90°C, while a cord with an XHHW insulation has a temperature rating of 105°C.Once you know the temperature rating of the cord, you can use Table 310.16 to find the temperature correction factor. For example, if the cord has a temperature rating of 90°C and the ambient temperature is 95°F, the temperature correction factor is 0.
82.You would then apply this correction factor to the ampacity from Table 400.5(B). For example, if the cord has an ampacity of 20 amps at 86°F, the ampacity at 95°F would be 20 amps x 0.82 = 16.4 amps. Flag for review