According to the NEC (National Electrical Code), a 2-inch concrete encasement does allow you to reduce the burial depth of PVC conduit from 18 inches to 12 inches under certain circumstances.

NEC Article 300.5(D)(3) (Residential Branch Circuits Rated 120 Volts or Less with GFCI Protection and Maximum Overcurrent Protection of 20 Amperes)

This section specifically allows for a reduced burial depth of

12 inches for PVC conduit containing residential branch circuits rated 120 volts or less, protected by GFCI devices, and with a maximum overcurrent protection of 20 amperes. Crucially, this is contingent on the conduit being encased in at least 2 inches of concrete.Important Considerations



Read and understand the NEC

This response is based on a general understanding of the NEC. Always consult the latest edition of the NEC and your local electrical codes for the most accurate and applicable requirements. Your local codes may be stricter than the NEC.

Type of Load

The reduction to 12 inches is often tied to specific types of circuits (e.g., residential branch circuits with GFCI protection as mentioned above). If it's not that type of circuit, the 18-inch depth might still be required, even with concrete encasement.

Location

Burial depth requirements can vary depending on the location (e.g., under driveways, roadways, or areas subject to heavy vehicular traffic).

Physical Protection

While the concrete provides physical protection, consider the overall environment. If the area is subject to unusual stress or potential damage, additional protection might be necessary.

Inspection

Ultimately, the final authority on whether a particular installation meets code requirements rests with the electrical inspector.

In summary:

While a 2-inch concrete encasement can* allow you to reduce the burial depth of PVC conduit under specific conditions (like residential branch circuits with GFCI protection and limited amperage), it's not a universal rule. Always consult the NEC, local codes, and your electrical inspector to ensure compliance. Don't assume that concrete automatically allows for a depth reduction without verifying the specific requirements for your situation. Flag for review