All references are based on the 2020 edition of the NEC.
Pick Your Poison
I spotted this mess while visiting a local apple orchard. The UF cable emerging from the ground without any protection is a violation of Sec. 340.12(10). UF is not permitted to be used where subject to physical damage. The broken rigid PVC conduit is a clue that physical damage is occurring at this location. When rigid PVC conduit is installed in areas where it is subject to physical damage, Sec. 352.10(F) requires the PVC conduit to be identified for that use. Schedule 40 PVC conduit should not be used in this area. Similarly, Sec. 352.12(C) prohibits using PVC conduit where subject to physical damage unless the conduit is identified for that use. Schedule 80 PVC conduit is identified for use in areas exposed to physical damage. The broken PVC conduit can allow moisture, water, dust, insects, and all kinds of other critters and contaminants into the raceway. In my interpretation, this would be a violation of Sec. 110.12(B), which prohibits damaged parts that may adversely affect the safe operation or mechanical strength of the equipment. On a positive note, at least the installer used expansion fittings where the PVC conduit emerges from the ground to accommodate for ground movement in accordance with Sec. 300.5(J).
Honey, I Shrunk the Conduits
Unfortunately, I see this type of shrinkage problem all too often on installations of rigid PVC conduit when expansion fittings are not installed. To compensate for thermal expansion and contraction, Sec. 352.44 requires expansion fittings to be used where the conduit length change is expected to be 1/4 in. or greater in straight runs between boxes, cabinets, elbows, conduit terminations, and other securely mounted items. Table 352.44 provides information to determine the length change of the conduit. For example, a 100-ft run of conduit would experience a length change of 4.06 in. when exposed to a temperature change of 100°F. This means a 6-ft run would experience a length change of approximately 1/4 in. when exposed to that same 100° temperature swing. Where I live in New England, the seasonal temperature can easily swing 100° or more as the weather transitions from summer to winter and back to summer again. Due to this temperature swing, expansion fittings must be used for PVC conduit runs of 6 ft or more in length; otherwise, the conduit run will not survive too long before the run bends and twists, the coupling breaks, or the PVC glue fails to hold the conduit in a connector, coupling, or fitting (as shown in this photo).
