For fixtures located close to a ballast, what is the minimum temperature rating required for conductors?

The minimum temperature rating required for conductors located close to a ballast is 90°C. This requirement is stipulated because ballasts, especially in fluorescent lighting systems, can generate significant heat during operation. Conductors that are rated at 90°C are more suited to withstand the elevated temperatures without degrading over time, ensuring that they maintain their integrity and function effectively in the long term.

Using conductors with a lower temperature rating, such as those rated at 60°C or 75°C, may not provide sufficient safety margins. These lower-rated conductors could experience insulation breakdown or other failure mechanisms when subjected to the higher thermal environment created by the ballast, potentially leading to safety hazards like short circuits or electrical fires. Consequently, for installations where heat is a factor, using conductors rated at 90°C helps ensure compliance with safety standards and the reliable operation of electrical systems.