What is the permitted box size when containing two 10/2 with ground MC cables plus one 14/2 with ground MC cable?

The correct choice involves understanding the NEC (National Electrical Code) volume allowances for electrical boxes when accommodating multiple conductors. In this case, when calculating box fill, it’s necessary to consider the number of conductors and any additional components that will occupy space within the box.

Each 10/2 with ground MC cable counts as three conductors (two for the hot and neutral wires, plus the ground), and the 14/2 with ground MC cable counts similarly. With two 10/2 cables and one 14/2 cable, the total would be:

• Two 10/2 cables: 2 cables × 3 conductors/cable = 6 conductors

• One 14/2 cable: 1 cable × 3 conductors/cable = 3 conductors

• Total = 6 + 3 = 9 conductors

According to the NEC, each conductor requires a minimum volume of space in the box. Additionally, space must be allocated for any device (like switches or receptacles) and any internal fittings (like the wire connectors).

The chosen box option provides enough cubic inches to accommodate the total fill of 9 conductors along with allowances for devices and fittings. The size and cubic inch