Stripping Type UF (Underground Feeder) cable, particularly UF-B, can be notoriously challenging due to its tough, moisture-resistant thermoplastic jacket that fully encases each conductor. However, with the right technique and tools, you can efficiently prepare this cable for connections.
Understanding UF Cable and Its Challenges
UF cable is a specific type of non-metallic (NM) cable designed for direct burial and wet locations, commonly used for outdoor lighting, detached garages, or other exterior applications. Unlike standard NM-B cable where conductors are individually insulated and then wrapped in a paper or plastic sheath before the outer jacket, UF cable's conductors (including the bare ground wire) are embedded directly within a solid block of thermoplastic material. This robust construction, while excellent for protection, makes it significantly harder to strip.
The primary difficulty lies in separating the individual insulated conductors and the bare ground wire from this dense, solid jacket without damaging the insulation of the inner wires.
Essential Tools for Stripping UF Cable
Having the correct tools makes the process much safer and more efficient.
| Tool Category | Specific Tool | Purpose |
|---|---|---|
| Cutting | Utility Knife / Box Cutter | For making the initial lengthwise cut in the outer jacket. |
| Wire Cutters / Diagonal Pliers | For cutting the cable to length and trimming excess jacket material. | |
| Stripping | Wire Strippers | For accurately stripping the insulation from individual conductors. |
| Gripping/Pulling | Lineman's Pliers / Slip-Joint Pliers | Essential for gripping the ground wire and pulling it through the jacket. |
| Safety | Safety Glasses | To protect your eyes from debris. |
| Work Gloves | To improve grip and protect hands. |
Step-by-Step Stripping Process for UF Cable
The key to stripping UF-B cable efficiently involves leveraging the bare ground wire as a rip cord.
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Prepare the Cable:
- First, determine the length of the outer jacket you need to remove. For most terminal connections, this is typically 6-12 inches.
- Ensure the cable is secured, either clamped in a vice or held firmly on a stable surface.
- Safety First: Always wear safety glasses and work gloves when working with sharp tools.
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Make the Initial Longitudinal Cut:
- Carefully use a sharp utility knife or box cutter to make a cut of about 2 inches along the concave center of the cable. The concave center usually indicates the path of the bare ground wire.
- Crucial Tip: Avoid cutting too deep to prevent nicking the insulation of the inner conductors. A shallow score is often enough to start.
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Utilize the Ground Wire as a Rip Cord:
- Once the initial cut is made, you should be able to expose a small section of the bare ground wire in the center.
- Using a pair of pliers (lineman's or slip-joint work well), firmly grasp the exposed bare ground wire.
- Pull the ground wire like a rip cord. As you pull, it will separate the outer jacket, splitting it cleanly along the length of the cable. Continue pulling the ground wire until you've split the jacket as far as needed. This technique minimizes the risk of damaging the insulated conductors.
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Separate and Trim the Jacket:
- Once the jacket is split by the ground wire, you can further peel back and separate the two halves of the jacket.
- Use your wire cutters or diagonal pliers to cleanly trim off the excess jacket material at the desired length.
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Separate Individual Conductors:
- With the main jacket removed, you will now have the insulated hot and neutral wires, along with the bare ground wire, still somewhat embedded or stuck together.
- Carefully pull or twist these individual conductors apart to fully separate them. They might require a bit of force or wiggling due to the tough encasement.
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Strip Individual Wire Insulation:
- Using appropriate wire strippers for the gauge of your UF cable (e.g., 14 AWG, 12 AWG), strip the insulation from the end of each individual hot and neutral conductor to the length required for your specific connection (typically 1/2 to 3/4 inch).
- Ensure the ground wire is also cut to the appropriate length.
Safety First
- Always Disconnect Power: Before working on any electrical wiring, ensure the power is completely shut off at the circuit breaker or fuse box. Verify with a non-contact voltage tester.
- Wear PPE: Safety glasses and work gloves are essential to prevent injuries.
- Sharp Tools: Exercise extreme caution when using utility knives and other sharp tools. Always cut away from your body.
- Avoid Nicks: Be meticulous to avoid nicking the insulation of the inner conductors during the initial jacket cut or while separating wires, as this can compromise safety and lead to short circuits or ground faults.
Tips for Success
- Warm the Cable: In cold weather, UF cable becomes even stiffer. Briefly warming the section you intend to strip (e.g., in a warm room) can make it more pliable and easier to work with.
- Practice: If you're new to stripping UF cable, practice on a scrap piece first to get a feel for the depth of cut and the amount of force needed.
- Maintain Sharp Blades: A dull utility knife will make the job harder and increase the risk of slippage and injury.
- Consider a Specialty Tool: While not strictly necessary, some specialized UF cable stripping tools are available that can automate parts of this process, though they may not always handle the rip-cord method as effectively as a utility knife and pliers.
By following these steps, you can effectively strip UF cable, ensuring safe and reliable electrical connections for your outdoor and underground wiring projects.
