31 (C) now aligns with the Code's broader language (like Article 392), allowing these smaller conductors and detailing how to calculate ampacities, the number of conductors permissible in cable trays, how to size cable trays correctly by width, layering or. The updated section 690. Getting the fill. In this installment of our Code Corner series, Ryan Mayfield focuses on the 2023 National Electrical Code (NEC) changes concerning cable trays, particularly section 690. Cable Size: The diameter of the cable affects how many can fit within the available space. Allowable Fill Capacity: To maintain proper ventilation and. NEC Article 392 explains cable trays, their components, appropriate wiring methods for cable trays, and instances where they are and are not permitted for use. Here is the summary of the main points found in NEC Article. Last month's article covered the basics of cable tray installation requirements, so this month, I will provide specific information on how to determine the ampacity of cables rated at 2,000V or less installed in cable trays.
[PDF Version]