When installing cables smaller than 4/0 in a cable tray, what should the allowable cable fill area NOT be less than?

The correct answer focuses on the requirement that the allowable cable fill area should not be less than the cross-sectional areas of the cables being installed. This is a crucial guideline to ensure that there is adequate space in the cable tray for the cables to be installed safely and efficiently.

Maintaining the appropriate fill area is important for several reasons, including preventing overheating and allowing for proper ventilation and heat dissipation. If the fill area is insufficient relative to the cross-sectional area of the installed cables, it could lead to excessive heat accumulation. This can jeopardize the integrity of the insulation and the overall safety of the installation.

By adhering to the requirement that the allowable cable fill area meets or exceeds the combined cross-sectional areas of the cables, installers help ensure compliance with safety standards and regulations, maintaining reliability and performance of the entire electrical system.