On 2010-03-15, Limp Arbor wrote:

Three 12/2 NM cables going into a plastic box with an outlet

conductors 6
grounds 1
Oulet 3

Devices are 2 per strap. So for a single gang duplex receptacle,
that's just 2.

Total 10

Total 9, as long as you don't have any cable clamps that extend into
the box.

10 times 2.25 = 22.5 cubic inch box needed.

9 * 2.25 = 20.25

Cheers, Wayne