What is the required size of a junction box with two 4" conduits, one 2" conduit, and two 1" conduits for a straight pull?

To determine the size of a junction box required for a straight pull involving multiple conduits, it is necessary to calculate the box fill based on the size and number of conduits involved. The National Electrical Code (NEC) provides guidelines for box fill calculations to ensure adequate space for conductors while minimizing the risk of overheating and ensuring safety.

For junction boxes, each conduit occupies a certain amount of space based on its size. Straight pulls typically require a specific calculation to make sure there is enough room for the wires without exceeding the box-fill limits.

In this scenario, with two 4" conduits, one 2" conduit, and two 1" conduits, the fill calculation needs to consider the number of conductors that will be in these conduits, as well as the necessary allowances. The calculation leads to a requirement of a box size that can accommodate all of these conduits adequately, plus additional space for securing the conductors.

When performing the corresponding calculations, the total required box size comes out to be 32 inches. This takes into account not just the physical dimensions but also adherence to electrical safety standards regarding fill capacity. Therefore, the required size of the junction box for a straight pull involving the specified conduits is indeed