There are six current-carrying conductors in a raceway that is to be installed in an area with an ambient temperature of 90°F. It is necessary to
consider the ampacity derating factor for the conductors in this scenario. The ampacity derating factor accounts for the effect of ambient temperature on the current-carrying capacity of the conductors.
To determine the appropriate derating factor, you would need to consult the National Electrical Code (NEC) or relevant local electrical codes as they vary. The NEC provides tables and formulas for determining the derating factor based on the number of current-carrying conductors in a raceway and the ambient temperature.
For example, according to NEC Table 310.15(B)(3)(a), for a raceway with six current-carrying conductors in an ambient temperature of 90°F, the derating factor is 80%. This means that you would need to multiply the ampacity of the conductors by 0.8 before determining the maximum allowable current.
Note that different cable types and insulation materials may have specific derating factors, so it is crucial to consult the appropriate codes and standards for accurate calculations.