How do you connect FMC to RMC or EMT?

The correct method to connect Flexible Metal Conduit (FMC) to Rigid Metal Conduit (RMC) or Electrical Metallic Tube (EMT) is by using a combination coupler/connector. This type of fitting is specifically designed to accommodate the different properties of FMC, which is flexible, and RMC or EMT, which are rigid. The combination coupler allows for a secure and effective transition between the two types of conduits, ensuring that there is a solid electrical connection while also maintaining the conduit system's overall integrity.

Using a straight connector would not be suitable as it lacks the necessary design to safely connect the differing types of conduits. Soldering is not appropriate for FMC, RMC, or EMT, as these conduits are typically joined using mechanical methods rather than soldered connections. A threaded coupling is also not the right choice since it is designed for rigid connections and would not accommodate the flexibility of FMC effectively. The key to proper installation is ensuring that the connection allows for the movement and flexibility required by FMC while still providing a secure connection to the more rigid systems.