Master Electrician Practice Exam

What should be used if rigid PVC conduit has to transition to an underground installation safely?

1. Plastic fittings

2. Threaded rigid metal conduit (RMC)

3. Flexible conduit

4. Standard PVC fittings

The correct answer is: Threaded rigid metal conduit (RMC)

When transitioning from rigid PVC conduit to an underground installation, it is essential to ensure a secure and reliable connection that protects against various environmental factors. Using threaded rigid metal conduit (RMC) is advantageous in this scenario because it offers superior strength and durability compared to other materials. This type of conduit is robust enough to withstand mechanical stress and is less susceptible to damage from external pressures, such as soil movement and compressive forces. Additionally, RMC is suitable for underground installations as it is designed to be watertight when properly installed, providing an appropriate level of protection against moisture and the elements. This material can help prevent rusting and corrosion, which is particularly important in buried applications where exposure to water and soil conditions can affect the integrity of electrical conduits over time. Other options, while potentially usable in certain contexts, may not provide the same level of strength or moisture protection required for a safe and long-lasting underground installation, making threaded rigid metal conduit the ideal choice for such transitions.