Which two conduit or raceway types are exempt from certain location requirements under metal-corrugated sheet roof decking?

The exemption of certain conduit or raceway types from location requirements under metal-corrugated sheet roof decking is rooted in their structural integrity and suitability for specific environments. In the context of the choices, both Intermediate Metal Conduit (IMC) and Rigid Metal Conduit (RMC) are constructed from robust materials that provide strong physical protection and are inherently resistant to corrosion and adverse environmental conditions.

These characteristics are essential in an installation setting where roof decking may be exposed to moisture, temperature changes, and other elements that could potentially impact the longevity and effectiveness of electrical conduits. The application of IMC and RMC is suitable for outdoor or harsh environments, making them less stringent regarding placement requirements when used under metal roofing.

On the other hand, conduit types like PVC (Polyvinyl Chloride) or EMT (Electrical Metal Tubing) have different properties and may not offer the same level of protection or corrosion resistance as IMC and RMC. For example, PVC is non-metallic and may have limitations in fire resistance and impact protection, while EMT is thinner and may require more stringent placement rules to ensure safety and compliance with electrical codes when used in vulnerable locations. Thus, IMC and RMC stand out as the primary choices exempt from