Which table is used to determine minimum box size when all conductors in the box share the same AWG size?

• A. Table 314.16(A)
• B. Table 314.27
• C. Table 310.15
• D. Table 400.102

Answer: (A)

Box fill calculations determine the minimum box size by summing the space needed for every conductor and any required components inside the box. When all conductors share the same AWG size, you can use a single per-conductor volume from the table that lists cubic inches per conductor for that gauge. Multiply that volume by how many conductors there are, and the box must have at least that much internal volume. This is why that table is used in this scenario—it provides the uniform per-conductor fill value, making the calculation straightforward.

If you had different gauges, you’d need to add up volumes using the appropriate per-conductor values for each size, which is why other tables that cover mixed sizes or different aspects of box design aren’t the right fit for this specific case.