Which box/cover combination will violate the NEC?

The scenario evaluates compliance with the National Electrical Code (NEC) regarding box fill calculations, which are essential for ensuring that electrical boxes have adequate space for conductors and devices without creating a fire hazard.

In the case of the specified box sizes and cover combinations, each box has an allowable fill volume that needs to be respected based on the number of conductors and devices used within the box. When analyzing the dimensions and fill capacities:

For the option in question, a 4 x 1-1/2 square box is paired with a 5.0 in³ industrial cover. To determine if this violates the NEC, one must assess whether the volume of the box, when filled according to the code requirements (considering the number of conductors and devices), exceeds the calculation limits.

The combination of box and cover would be deemed acceptable only if the total fill does not surpass the listed capacity for the box size used. If the conductor fill calculations indicate that the box cannot safely accommodate the devices and conductors as listed in the NEC standards, then this combination would indeed violate the NEC.

The solution requires careful consideration of the specific dimensions of the boxes in relation to their fill volumes, which are determined by the number of conductors, devices, and