What is the minimum length for a pull box used for two runs of three-inch RMC installed adjacent to each other?

To determine the minimum length for a pull box used for two runs of three-inch rigid metal conduit (RMC) installed adjacent to each other, we refer to the standards and best practices for pull box sizing.

A pull box must be large enough to accommodate the bends in the conduit, as well as ensure that the wires can be easily pulled through without excessive strain or risk of damage. The National Electrical Code (NEC) provides guidelines for pull box dimensions, which take into account the size and number of conductors, as well as the size of the conductors’ entry into the box.

In the case of two runs of three-inch RMC, it’s common practice to measure the length of the pull box based on the interior width of the conduits and the necessary working space that would allow for easy installation and maintenance of the wires. The standard recommendation for a pull box that handles two three-inch conduits typically leads to the conclusion that a minimum length of 24 inches is needed to provide adequate space when accounting for both the conduits and the necessary pulling angles. This ensures that enough room is available to facilitate the pulling of wires through the conduits without creating a potential pinch point or causing undue wear and tear on the wires.

Thus