How many 12 AWG, THHN conductors are allowed in a 4 in. x 1.5 in. square box with internal cable clamps?

To determine how many 12 AWG, THHN conductors can fit in a 4 in. x 1.5 in. square box with internal cable clamps, it's essential to reference the National Electrical Code (NEC) guidelines, specifically the section that addresses box fill calculations.

The proper method for calculating the maximum number of conductors includes the following steps:

1. Box Volume: A standard 4 in. x 1.5 in. square box has a specific volume, which is used in the calculations.

2. Conductor Fill: Each 12 AWG conductor typically requires a certain volume for safe installation. According to NEC, each insulated conductor counts for a specific volume plus additional volume for clamps or devices in the box.

3. Total Calculation: After considering the volume occupied by the conductors, adjustments for cable clamps or other items, one computes the total number of conductors that can fit within the box's volume.

In this scenario, the calculations lead to a maximum of 8 conductors that can be accommodated in the box when following NEC guidelines. This means selecting the choice that corresponds to 8 conductors is accurate based on the standard fill requirements and volume calculations related to the