How many 16 gauge conductors are permitted in a 4 x 1 1/2 inches square box?

How many 16 gauge conductors are permitted in a 4 x 1 1/2 inches square box?

• A. 8
• B. 14
• C. 10
• D. 12

Answer: (D)

Box fill calculations determine how many conductors a box can hold. Each conductor that originates outside the box and terminates or is spliced inside counts as one conductor toward the box’s volume, and all equipment-grounds together count as one conductor, with any internal clamps or device yokes adding extra counts as specified. For this size, the box is rated at 15 cubic inches of internal volume. A 16-gauge conductor requires 1.25 cubic inches of space for box fill. Dividing the box volume by the per-conductor volume gives 15 ÷ 1.25 = 12. Therefore, twelve 16-gauge conductors are permitted in this box. If there are grounding conductors, clamps, or a device yoke, those could add to the count and slightly reduce the number that can fit, but in this standard calculation the limit is twelve.

Box fill calculations determine how many conductors a box can hold. Each conductor that originates outside the box and terminates or is spliced inside counts as one conductor toward the box’s volume, and all equipment-grounds together count as one conductor, with any internal clamps or device yokes adding extra counts as specified. For this size, the box is rated at 15 cubic inches of internal volume. A 16-gauge conductor requires 1.25 cubic inches of space for box fill. Dividing the box volume by the per-conductor volume gives 15 ÷ 1.25 = 12. Therefore, twelve 16-gauge conductors are permitted in this box. If there are grounding conductors, clamps, or a device yoke, those could add to the count and slightly reduce the number that can fit, but in this standard calculation the limit is twelve.