Which conduit type is thick-walled and suitable for direct burial?

• A. Thin wall, requires concrete encasement
• B. Thick wall, direct buried
• C. Ultraviolet and flame resistant
• D. Not used for straight line conduit

Answer: (B)

Direct burial requires a conduit that can withstand soil pressure and potential impacts without additional protection. Thick-walled conduit provides the mechanical strength to be buried directly, meeting the soil-load and protection needs without needing concrete encasement. Thin-walled conduit, by contrast, often requires extra protection such as concrete encasement to handle the same burial conditions, making it less suitable for direct burial in standard installations. Material properties like ultraviolet resistance aren’t the deciding factor for burial since buried conduit isn’t exposed to sunlight. And conduit is indeed used for straight-line runs, so that claim isn’t accurate.