Which box size is suitable for installing three 10 AWG conductors and three 6 AWG conductors?

To determine which box size is suitable for installing three 10 AWG conductors and three 6 AWG conductors, it’s necessary to consider the fill capacity of each box based on the NEC (National Electrical Code) requirements.

The NEC provides a set of guidelines for box fill calculations. Each conductor and device inside an electrical box occupies a certain amount of space or volume, which means that the overall size of the box must accommodate this volume without exceeding the rated fill capacity.

For conductors, 10 AWG conductors typically have a fill capacity of 2 cubic inches, whereas 6 AWG conductors usually have a fill capacity of 3 cubic inches. Therefore, for three 10 AWG conductors, the total volume needed is 3 conductors x 2 cubic inches = 6 cubic inches. For three 6 AWG conductors, this amounts to 3 conductors x 3 cubic inches = 9 cubic inches. The total volume necessary for the box is thus 6 + 9 = 15 cubic inches.

In this context, the chosen box size of 4 11/16 in. × 2 1/8 in. square box is appropriate because it has a volume that exceeds