Connecting a flex connector involves properly securing flexible metal conduit (FMC) or armored cable (AC/BX) to an electrical box or enclosure. This ensures both mechanical stability and electrical continuity, crucial for safe wiring installations.
Understanding Flex Connectors
Flex connectors are essential components in electrical wiring, providing a secure and code-compliant method for transitioning from flexible conduits or armored cables into rigid electrical boxes. They protect wires from sharp edges, provide strain relief, and in some cases, contribute to the grounding path.
Tools and Materials You'll Need
Before starting, gather the necessary tools and materials:
- Flex Connector: Matching the size and type of your flexible conduit or armored cable.
- Flexible Metal Conduit (FMC) or Armored Cable (AC/BX): The cable you are connecting.
- Electrical Box: The destination for your cable.
- Cable Cutters: For precise cuts.
- Wire Strippers: To remove insulation from individual conductors.
- Screwdriver: For tightening set screws on the connector.
- Locknut Wrench or Pliers: To tighten the locknut on the connector.
- Anti-Short Bushing (for AC/BX): A small plastic or fiber bushing to protect wires from the cable's sharp edges.
- Utility Knife (optional): For scoring cable jacket.
- Personal Protective Equipment (PPE): Safety glasses and gloves.
Step-by-Step Guide to Connecting a Flex Connector
Follow these steps to ensure a secure and compliant connection:
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Prepare the Cable:
- Measure and Cut: Determine the required length of flexible conduit or armored cable and cut it cleanly.
- Remove Outer Sheathing: Carefully remove the outer metal sheathing of the flexible cable, exposing the insulated conductors and any bonding strip. For armored cable (AC/BX), ensure you cut the spiral armor cleanly to avoid sharp edges.
- Insert Anti-Short Bushing (for AC/BX): If using armored cable, insert an anti-short bushing between the conductors and the cut end of the metal armor. This critical step protects the wire insulation from being abraded by the sharp edges of the metal sheathing.
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Insert Cable into the Flex Connector:
- Slide the prepared end of the flexible conduit or armored cable into the opening of the flex connector.
- Ensure the cable is fully seated within the connector body.
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Secure the Cable within the Connector:
- Tighten Set Screw(s): Use a screwdriver to firmly tighten the set screw(s) on the side of the flex connector. This clamps down on the flexible cable, holding it securely in place and providing strain relief. For squeeze connectors, use a wrench or pliers to tighten the compression nut.
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Attach Connector to the Electrical Box:
- Insert into Knockout: Locate an appropriate knockout hole on your electrical box. If necessary, remove the knockout. Insert the threaded end of the flex connector through the knockout hole from the outside of the box.
- Thread the Locknut: From inside the electrical box, thread the locknut onto the threaded portion of the flex connector.
- Apply Tension (Trick!): As you thread the locknut, it's helpful to maintain gentle tension on the flexible conduit or cable itself. This helps to hold the connector firmly against the box, making it easier to fully thread and tighten the locknut securely.
- Tighten Locknut: Use a locknut wrench or pliers to firmly tighten the locknut. Ensure it's snug against the inside of the box for a stable and grounding connection.
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Final Checks and Trimming:
- Inspect Connection: Verify that the cable is securely held by the connector and that the connector is firmly attached to the electrical box.
- Trim Excess String: If you're working with armored cable that has an internal bonding strip or string for the anti-short bushing, and there's any excess string protruding after the connection is made, cut it off neatly.
Types of Flex Connectors
Flex connectors come in various designs, primarily categorized by how they secure the cable:
| Connector Type | Description | Common Uses |
|---|---|---|
| Set-Screw Type | Uses one or more screws to clamp down on the cable. | FMC, AC/BX, sometimes NM cable with appropriate bushings |
| Squeeze Type | Features a compression nut that tightens around the cable. | FMC, Liquidtight Flexible Metal Conduit (LFMC) |
| Snap-In Type | Designed for quick installation; simply pushes into the knockout. | AC/BX, often used for speed and convenience |
Safety Considerations
Always prioritize safety when working with electricity:
- Turn Off Power: Before starting any electrical work, always ensure the power to the circuit is turned off at the breaker or fuse box. Verify with a voltage tester.
- Read Instructions: Follow the manufacturer's instructions for the specific flex connector you are using.
- Local Codes: Adhere to all local electrical codes and the National Electrical Code (NEC) for proper installation.
- Proper Tools: Use insulated tools when working with electrical components.
By following these steps, you can confidently and safely connect a flex connector, ensuring a robust and compliant electrical installation.
