What is the minimum box volume requirement for a 120/240-volt, 50-ampere range receptacle supplied by an 8-3 NM-B cable?

To determine the minimum box volume requirement for a 120/240-volt, 50-ampere range receptacle supplied by an 8-3 NM-B cable, it is essential to follow the National Electrical Code (NEC) guidelines for box fill calculations.

An 8-3 NM-B cable typically contains three conductors plus a ground wire. According to NEC rules, each conductor must be allotted a certain volume within the electrical box to ensure safe and effective operation. For non-metallic sheathed cable, the volume allowances are as follows: each conductor is typically assigned 2 cubic inches, and each additional conductor or ground wire also adds to the total volume requirement.

In this case, there are three conductors (two hot wires and one neutral) plus a ground wire, which totals four conductors. Therefore, we can calculate the volume needed:

• 4 conductors × 2 in³ per conductor = 8 in³

However, there are also additional volume allowances required for the box itself, usually adding volume for the internal box structure and devices mounted within it, such as the receptacle. Typically, the box volume requirement will also include an additional allowance for devices, often around 2 cubic inches for the recept