HDPE conduit larger than what size shall not be used?

• A. 2 inch
• B. 6 inch
• C. 3 inch
• D. 4 inch

Answer: (B)

HDPE conduit is favored for underground runs because it’s corrosion-resistant and easy to pull through long trenches. But there’s a practical size limit: it is not used in diameters larger than six inches. Beyond that, pulling large cables becomes difficult, fittings and joints are harder to obtain or install, and the method for joining and sealing becomes more complex and costly. For bigger service conduits, other types of ducting (like rigid metal or concrete-encased duct) are preferred. So the maximum size you’d typically use is six inches, and anything larger isn’t used in standard practice.