Final answer:
The allowable ampacity for a #12 TW copper conductor in a raceway with an ambient temperature of 75℉ is typically 25 amperes, as this temperature is within the standard operating range provided by the NEC.
Step-by-step explanation:
The question asks about the allowable ampacity of a #12 TW copper conductor in a raceway with an ambient temperature of 75℉. The ampacity of a conductor is determined by its physical properties and the environmental conditions in which it operates. According to the National Electrical Code (NEC), the ampacity for a #12 TW copper conductor is typically 25 amperes at an ambient temperature of 30℃ (86℉). However, the given ambient temperature is 75℉, which is within the acceptable operating range, so the ampacity remains the same since the ambient temperature does not exceed the NEC reference temperature. It's crucial to ensure that the conductor's ampacity is not exceeded to avoid overheating and potential safety hazards.