Yes, it's typical and considered good practice to install PVC expansion fittings on conduits protruding vertically from asphalt in most situations, even if the NEC doesn't explicitly mandate it specifically for asphalt. The inspector is likely correct in their assessment.Here's why: Thermal Expansion of PVC

PVC has a high coefficient of thermal expansion. This means it expands and contracts significantly with temperature changes. Asphalt surfaces can get extremely hot in direct sunlight, especially in warmer climates. This heat will transfer to the conduit, causing it to expand.

Stress on Conduit and Connections

Without an expansion fitting, the expansion of the PVC conduit will exert significant stress on the conduit itself, the junction box, and the connections within the box. This stress can lead to: Cracking of the conduit. Disconnection of fittings. Damage to conductors and terminations. Failure of the junction box.

Ground Movement

Asphalt is not a perfectly stable surface. It can shift and settle over time. Even small movements can place additional stress on rigid conduit runs.

Code Justification (Even if not Explicit)

While the NEC may not specifically mention asphalt, consider these sections:

300.7 Expansion Fittings

"Raceways shall be provided with expansion fittings where necessary to compensate for thermal expansion and contraction." The "where necessary" is key. The inspector is arguing that in this situation, it is necessary.

300.7(B)

"Exposed raceways shall be of materials suitable for the environment in which they are installed." Asphalt is a harsh environment due to heat and potential chemical exposure.

Industry Best Practice

Even if not explicitly required by the NEC in all cases, many experienced electricians and engineers consider expansion fittings essential for vertical conduits rising from asphalt. They are a relatively inexpensive way to prevent potentially costly repairs in the future.

Inspector Authority

Inspectors have the authority to interpret the code and require practices that ensure a safe and reliable electrical installation. If the inspector is requiring expansion fittings, it's wise to comply.

Regarding your specific situation



Relocating the Box

It's highly likely you'll need to relocate the junction box to accommodate the expansion fittings. Measure the approximate total length of each exposed PVC conduit and use a PVC expansion fitting chart or calculator to determine the necessary expansion allowance for your area's temperature range.

Considerations

Think about where the expansion will be directed. Make sure the expansion fitting does not interfere with anything in the area or create a tripping hazard. Use expansion fittings with the proper size and travel range for your conduit size and climate. Follow the manufacturer's instructions for installing the expansion fittings. Ensure the junction box is securely mounted to minimize movement.

In Summary:

While the NEC might not explicitly say "you MUST use expansion fittings for conduits rising from asphalt," the thermal expansion properties of PVC and the harsh environment created by asphalt make it a very prudent and often required practice. Listen to your inspector; it's far better to comply and install the expansion fittings than to risk future problems and potential code violations. Relocating the box to accommodate the fittings is likely the best course of action. Flag for review