The minimum required depth for an outlet box that will support a device but does not enclose any conductors is:

The minimum required depth for an outlet box that supports a device but does not enclose any conductors is set at 1/2 inch. This depth is established to ensure that the device can be securely mounted while allowing sufficient space for the mounting screws and any associated hardware. A box with this depth provides adequate support for devices such as switches and outlets without the added need for extra depth that would accommodate wiring, as it is specifically noted that no conductors will be enclosed within it. This requirement ensures safety and functionality within the electrical installation standards.

Larger depths, such as 3/4 inch, 1 inch, or 1 1/2 inches, while potentially suitable for various applications involving wiring or multiple devices, aren't necessary in this specific scenario where conductors are not present. Thus, adhering to the specified minimum of 1/2 inch meets the essential needs of device support without excess material costs or bulk.