What is considered the most common rigid non-metallic conduit?

Rigid PVC, or Polyvinyl Chloride, is widely recognized as the most common rigid non-metallic conduit due to its durability, versatility, and resistance to environmental conditions. It is often used in underground installations, as well as in areas where moisture and certain chemicals are present. Its strength allows it to withstand physical stresses while also being lightweight and easy to handle during installation.

Further, rigid PVC can be easily cut and joined using solvent cement, which simplifies construction processes. Additionally, it is less expensive compared to alternative materials, making it a cost-effective choice for many electrical and plumbing installations.

While other options like flexible PVC and polyethylene are used in specific applications, neither of them has the same level of prevalence and general utility in rigid conduit applications as rigid PVC. Standard PVC, which is often synonymous with rigid PVC, also does not specifically refer to a non-metallic conduit but is a broader term for various forms of PVC products.