What is the minimum temperature rating for branch circuit conductors installed near ballasts?

The minimum temperature rating for branch circuit conductors installed near ballasts is 90° C. This rating is important because ballasts can generate significant heat during operation, and conductors must be able to withstand higher temperatures to ensure safety and reliability. The 90° C rating allows for adequate operation in environments where thermal conditions may be elevated due to the proximity to ballasts, which might occur in lighting fixtures, particularly in commercial or industrial applications.

Low-temperature-rated conductors might not be able to handle the heat produced, leading to insulation breakdown, which could result in conductor failure or even electrical fires. Therefore, the code specifies a minimum of 90° C for the conductors in this scenario to ensure they remain safe and functional over time, taking into account the heat generated by ballasts.