In a metal junction box with 27 cubic inches containing six 12 AWG wires, what is the maximum number of 10 AWG conductors that may be added?

To determine the maximum number of 10 AWG conductors that can be added to a metal junction box with 27 cubic inches containing six 12 AWG wires, we need to consider the box fill calculations as per the National Electrical Code (NEC) guidelines.

For box fill calculations, each type of conductor has a specific volume allowance. Typically, a 12 AWG wire requires 2.25 cubic inches of space, while a 10 AWG wire requires 2.5 cubic inches.

First, we calculate the total volume occupied by the existing six 12 AWG wires:

• Volume for six 12 AWG wires = 6 wires × 2.25 cubic inches/wire = 13.5 cubic inches.

Now, subtract this volume from the total available volume of the box:

• Remaining volume = 27 cubic inches (total box space) - 13.5 cubic inches (occupied by 12 AWG wires) = 13.5 cubic inches.

Next, we can determine how many 10 AWG conductors can fit into this remaining space. Each 10 AWG wire requires 2.5 cubic inches of space, so we calculate:

• Maximum number of 10 AWG