A two-gang box contains cables connected to a duplex receptacle and a switch. What is the minimum required cubic inch volume of the box?

To determine the minimum required cubic inch volume of a two-gang box containing cables connected to a duplex receptacle and a switch, the calculation for box volume takes into account the conductors and devices that will occupy space within the box.

In this scenario, let's break down the volume requirements:

1. Device Volume: For a duplex receptacle, the NEC (National Electrical Code) typically considers that it occupies 2 cubic inches of the box volume. A switch also adds 2 cubic inches for its space.

2. Conductor Volume: For every two conductors entering or leaving the box, an additional volume of 2 cubic inches is required. Each cable typically consists of two conductors plus a ground, which can influence the count. Depending on how many cables are entering the box, the calculated volume will increase accordingly.

3. Ground Wires: If ground wires are assessed, you will need to add another cubic inch for each ground wire present.

Putting this all together, for a two-gang box accommodating a duplex receptacle and a switch, you calculate the base volume requirement as follows:

• Device volume: 2 cu. in. for the receptacle + 2 cu. in. for the switch