Secure flexible conduit to a distribution box using the correct connector, locknut, and bushing to ensure mechanical protection and proper grounding.

Step 1: Select the Appropriate Conduit and Connector

• Flexible Metallic Conduit (FMC): Spiral-wound metal used indoors; requires a squeeze-type connector that clamps onto the conduit ribs .
• Liquid-Tight Flexible Metallic Conduit (LFMC): Metal core with a waterproof PVC jacket for wet or outdoor locations; requires a compression-style connector to seal against moisture .
• Non-Metallic Flexible Conduit (NMFC): Plastic-based conduit for dry residential areas; connectors may vary and often require separate grounding .

Step 2: Prepare the Conduit

• Measure the routing path and cut the conduit to length, adding 2–3 inches of slack for bends or movement .
• Strip the outer jacket or metal spirals if necessary to fit the connector, ensuring a clean, smooth end.

Step 3: Install the Connector

• Insert the conduit into the connector. For squeeze-type connectors, tighten the screws to clamp the conduit securely .
• For compression-style connectors, tighten the nut to compress the gasket against the conduit jacket, creating a moisture-tight seal .

Step 4: Attach to the Distribution Box

• Remove the appropriate knockout from the box.
• Insert the connector through the knockout and secure it from inside the box using a threaded locknut .
• Ensure the locknut cuts into the metal of the box to establish a low-resistance electrical bond.

Step 5: Install an Insulating Bushing

• Slide a bushing onto the connector inside the box to protect wire insulation from sharp edges .
• This step is critical for preventing chafing and maintaining long-term safety.

Step 6: Pull the Wires

• Feed the flexible wire through the conduit into the box carefully, avoiding kinks or sharp bends.
• Connect the wires to the appropriate terminals in the distribution box according to electrical codes.

Tools and Materials Needed

• Conduit cutter or utility knife
• Screwdrivers (insulated handles)
• Drill with hole saws (if needed)
• Tape measure
• Squeeze or compression connectors
• Locknuts and insulating bushings
• Flexible conduit (FMC, LFMC, or NMFC)

Safety and Compliance

• Always select connectors listed for the specific conduit type to comply with NEC Section 110.3(B) .
• Ensure a continuous grounding path by using metal boxes and properly tightened connectors.
• Avoid using rigid or EMT fittings on flexible conduit, as this can compromise mechanical integrity and safety . Following these steps ensures a secure, code-compliant, and durable connection between flexible wire and a distribution box, protecting both the wiring and the electrical system from mechanical and environmental hazards.