A 4-square box with two receptacles installed adds how many additional conductors to the fill allowance?

The correct answer indicates that a 4-square box with two receptacles installed adds four additional conductors to the fill allowance. This is based on how electrical boxes are sized and filled when accommodating conductors and devices within them.

In the context of electrical installation, a 4-square box typically has a volume that accommodates various conductors based on the National Electrical Code (NEC). Each device like a receptacle adds to the total fill requirement. When installing a receptacle, you need to consider the conductors entering and exiting the box, as well as the conductors associated with each device.

For receptacles, each generally requires two conductors (one for the hot and one for the neutral), plus a ground conductor. Therefore, for two receptacles, the calculation would be:

• 2 receptacles x 2 conductors (hot and neutral) = 4 conductors

• Additionally, each receptacle usually has its ground (though grounds may be counted separately).

Thus, a total of four additional conductors is a reasonable and standard figure to account for in the fill allowance of the box, aligning with the NEC's requirements for box fill calculations.