What is the minimum length for a handhole enclosure when a run of three and one half-inch PVC is installed for a straight pull through the enclosure?

The minimum length for a handhole enclosure when dealing with three and one-half-inch PVC in a straight pull situation is determined by the need for adequate space to accommodate the bends and fittings while allowing for safe access and maintenance.

For a straight pull, the National Electrical Code (NEC) and various industry standards establish guidelines that include factors like the size of the conduit, the pull length, and the accessibility for installation and future maintenance. Specifically, the standard practice outlines that the length of the enclosure should be at least 24 inches plus an additional length to account for the conduit size and bending radius.

For three and one-half-inch PVC, the additional length required beyond the base minimum ensures that the conduit can make the necessary bends without exceeding pull tension limits and that workers have enough space to work effectively without damaging the wiring. This cumulative requirement leads to a minimum enclosure length of 28 inches, being the best fit for operational constraints and safety measures.

This makes 28 inches the correct choice, as it meets the minimum requirements while promoting safe installation practices.