How to Cap Off Electrical Wires Safely

Put a cap on electrical wire hazards with these steps

Female electrician wiring new house
Photo: Johner Images / Johner Images Royalty-Free / Getty Images
Female electrician wiring new house
Photo: Johner Images / Johner Images Royalty-Free / Getty Images
Alison Kasch
Written by Alison Kasch
Contributing Writer
Updated May 24, 2023
SKILL LEVEL
Challenging
COMPLETION TIME
30 minutes
COST
$25–$50
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What you'll need:
TOOLS
  • Wire stripper
  • Non-contact voltage tester
SUPPLIES
  • Wire nuts/ wire connectors
  • Electrical tape (optional)
  • Blank electrical plate (if capping wires in an electrical box)

If you’re wiring a house or embarking on a major remodeling project, you’ll likely encounter exposed electrical wires that can create a serious hazard if left uncovered. Learning how to cap off electrical wires ensures the exposed ends are covered, preventing electrical shocks, short circuits, electrical fires, and possible damage to your home’s electrical system. 

As with any project involving electrical work, safety is paramount, and it’s best to hire a professional electrician rather than doing it yourself. However, if you have electrical experience, it’s possible to cap wires safely by following a few steps and using the right tools. Here’s how to cap off electrical wires safely and effectively.

Prepping to Cap Off Electrical Wires

It’s crucial to shut the power off at the circuit breaker before capping off electrical wires. This important electrical safety tip eliminates the potential for electrical shock and helps create the safest possible environment for working with the wires. 

After you’ve shut off the power, it’s also important to use a non-contact voltage tester to ensure there’s no charge in the wires you’re planning to adjust. Once your meter reads 0, you can proceed to the next steps.

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  1. Trim the Wires So They’re Flush With the Insulation

    Handyman cutting electrical wires in electrical box
    Photo: m-gucci / iStock / Getty Images Plus / Getty Images

    Once you’ve shut the power off at the breaker and double checked there is no electrical charge in the wires, use wire cutters to trim the ends of the wires until they are flush with their protective casing. This step will provide you with a straight section of conductor to work with, ensuring a secure connection.

  2. Strip the Insulation

    Technician removes electrical wire insulation
    Photo: Grigorev_Vladimir / iStock / Getty Images Plus / Getty Images

    Using wire strippers, carefully strip away roughly one inch of insulation. To strip the wire, place the wire in the appropriate stripping notch of the wire strippers, squeeze the handles, and pull the strippers toward the end of the wire. It may take a few attempts to completely strip the wire.

  3. Screw on a Wire Nut

    Electrician screws on wire nut over stripped wire
    Photo: Grigorev_Vladimir / iStock / Getty Images Plus / Getty Images

    Next, take a wire nut that corresponds with the size and quantity of the wires you’ll be capping off. Hold the stripped ends in one hand, and use the other to screw the wire nut clockwise over the stripped ends. Once the nut is in position, tug gently to ensure the wires are held together firmly.

  4. Apply Electrical Tape Over the Wire Nut

    Handyman applying electrical tape over wires
    Photo: AntonioDiaz / Adobe Stock

    To provide another layer of protection, wrap electrical tape tightly over the wire nut and connected wires. Start a few inches away from the wire nut and continue wrapping, extending it beyond the nut onto the insulated section of the wires.

  5. Repeat Until All Wires Are Capped

    Electrician installing new junction box cover
    Photo: photovs / iStock / Getty Images Plus / Getty Images

    Lastly, repeat the previous two steps for each wire until every wire is securely capped. If the capped wires are in a device box, such as an electrical outlet box or junction box, then it’s necessary to install a blank cover to comply with National Electrical Code (NEC) regulations. 

DIY vs. Hiring a Pro

When it comes to any project involving electrical wiring, it’s always best to enlist the expertise of a licensed local electrician. While capping off electrical wiring might seem like a fairly straightforward task, it can still be very hazardous, and safety should always be the top priority. 

By hiring a professional electrician, you can be assured that the job is done safely and correctly. Keep in mind that hiring an electrician costs an average of $50 to $100 per hour.

Frequently Asked Questions

Yes, covering exposed wires is necessary for several important reasons. Exposed electrical wires pose significant risks, such as electrical shocks, fires, short circuits, and potential damage to your home’s electrical system. By properly insulating and protecting the wires, you can minimize the potential for accidents, prevent electrical fires, and ensure your electrical system stays intact. 

No, you should always use proper electrical wire caps to safely cap off electrical wires. Electrical tape isn’t as durable as electrical caps and can deteriorate and separate over time, exposing the live wires. The only way to use electrical tape for this project is to wrap it around the caps themselves to reinforce them and create an even stronger connection, preventing an electrical emergency.

No, it’s extremely dangerous to cap off live electrical wires. Working with live wires puts you at serious risk of electric shock, which can cause injury or even be fatal. Whenever you need to cap off electrical wires or complete any electrical work in general, it’s essential to shut the power off at the breaker before you begin.

No. When applied properly, electrical tape is designed to be an insulating material with high resistance to electricity. It can reinforce electrical connections and act as a safeguard to help ensure the electrical current stays within its designated pathways. However, it’s important to note that it can break down over time and you should never use it as a replacement for electrical wire caps.

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Learn more about our contributor
Alison Kasch
Written by Alison Kasch
Contributing Writer
Alison is a Chicago-based writer who has spent the last seven years focusing her content on everything inside and outside the home.

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