Journeyman Electrician Practice Exam

What is the volume that must be counted for an unbroken size 12 AWG conductor looped inside a junction box with over 12 inches of free conductor?

1. 2.00 cubic inches

2. 3.50 cubic inches

3. 4.50 cubic inches

4. 5.50 cubic inches

The correct answer is: 4.50 cubic inches

When calculating the volume required for conductors in a junction box, it's important to understand the National Electrical Code (NEC) guidelines regarding conductor fill. For a size 12 AWG (American Wire Gauge) conductor, the NEC states that each conductor typically requires a specific volume allowance based on its size, which contributes to the overall box fill calculation. For conductors like the 12 AWG, the volume specified is 2.00 cubic inches per conductor. In the case presented, since the conductor is looped and there is over 12 inches of free conductor, it is treated as one continuous length for the purpose of volume calculation. This often leads to additional volume being added due to the 'free' section in the box, which accounts for the loops and serviceability of the conductor. By taking one AWG 12 conductor and a potential allowance for the free length, the total calculated volume comes to 4.50 cubic inches. The statement advocates for including the entirety of the conductors as well as considering the applicable allowances for free conductor lengths in junction boxes, confirming the answer of 4.50 cubic inches is appropriate since it aligns with the practice and code established for such scenarios. This is why the correct assessment of 4