How many 10 AWG conductors are allowed in a 4 in. x 1½ in. metal square box?

To determine how many 10 AWG conductors can be placed in a 4 in. x 1½ in. metal square box, it is essential to refer to the National Electrical Code (NEC) guidelines, specifically regarding box fill calculations.

The box fill calculation begins with understanding the volume of the box and the space taken up by the conductors. A 4 in. x 1½ in. square box has a specific volume capacity measured in cubic inches. For each conductor, there is a standard volume requirement based on its gauge.

For 10 AWG conductors, each one takes up 2 cubic inches of space. The NEC allows additional volume for devices like switches or for the volume occupied by clamps, but if we focus on the conductors themselves in a simple scenario without additional devices, we would assess the cubic volume of the box.

Calculating the volume of the box, a 4 in. x 1½ in. box holds approximately 14.5 cubic inches. Since each 10 AWG conductor occupies 2 cubic inches, you can divide the total volume by the individual conductor space to find how many can fit.

Performing the calculation: 14.5 cubic inches / 2 cubic