What aspect must be ensured for the installation of nonmetallic boxes in relation to conductor entry?

For the installation of nonmetallic boxes, it is essential to ensure that these boxes must support the lowest rate of conductor. This requirement pertains to the proper sizing and selection of the box in relation to the conductors being used. The purpose of this criterion is to prevent overcrowding and ensure that there is adequate space within the box for heat dissipation, which helps to maintain safe operating temperatures for the conductors.

If the box does not support the lowest rate of conductor, it could lead to overheating, insulation breakdown, or even potential fire hazards due to insufficient space for the proper accommodation of the electrical wiring. Therefore, ensuring that nonmetallic boxes align with the appropriate conductor rating is crucial for safety and code compliance in electrical installations. This concept reinforces the importance of understanding the electrical system's specifications and usage to maintain optimal and safe functionality.