How to wire an additional outlet in the garage

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Introduction

Whether you’re adding power for tools, chargers, or appliances, installing an additional outlet in your garage can make the space far more functional. Learning how to wire an additional outlet in the garage will allow you to power more devices without running messy extension cords across the floor. While this is a manageable project for many DIYers, it does involve electrical work—so safety and adherence to code are essential.

Why Adding an Outlet Matters for Your Garage

Garages are often underpowered with only one or two outlets, which can be inconvenient or even unsafe. Adding another outlet offers several benefits:

  • Convenience: Plug in tools and chargers where you need them most.
  • Improved safety: Reduces the need for extension cords that can cause tripping or fire hazards.
  • Better organization: Allows for more flexible workbench and tool placement.
  • Increased functionality: Supports higher-power tools without overloading existing outlets.

If done correctly, an additional outlet can make your garage more efficient and enjoyable to work in.

Step-by-Step Guide to Wiring an Additional Outlet in the Garage

Safety First

Important: If you’re unfamiliar with electrical wiring or your local electrical code, hire a licensed electrician. Always turn off power at the breaker before starting and verify with a voltage tester.

1. Determine the Power Source

You’ll need to tap into an existing electrical circuit. Common options include:

  • An existing garage outlet on the same wall.
  • A nearby junction box.
  • A dedicated 20-amp circuit for garage outlets (recommended for power tools).

Pro Tip: Check the circuit’s load—don’t add an outlet to a circuit that’s already near capacity.

2. Gather Tools and Materials

You’ll need:

  • New electrical outlet (receptacle)
  • Electrical box (old-work box for drywall, surface-mount box for exposed walls)
  • Wire (usually 12/2 NM-B for 20-amp, 14/2 NM-B for 15-amp circuits)
  • Wire nuts
  • Electrical tape
  • Screwdriver set
  • Wire strippers/cutters
  • Drill with spade bit (for boring through studs)
  • Voltage tester
  • Pencil and measuring tape
  • Stud finder

3. Plan Outlet Location

  • Choose a spot that’s convenient for your needs.
  • Standard outlet height is 12–18 inches from the floor, but adjust as needed for workbenches or appliances.
  • Avoid placing the outlet behind large immovable objects.

Pro Tip: For garages, consider installing outlets at counter height near work areas for tool use.

4. Turn Off Power

Shut off the breaker controlling the circuit you’ll be working on. Use a voltage tester to confirm there’s no power in the source outlet before proceeding.

5. Cut the Hole for the New Outlet

  1. Use a stud finder to locate studs and avoid cutting into them.
  2. Trace the outline of the electrical box on the wall.
  3. Cut the hole using a drywall saw (for finished walls) or mount a surface box (for exposed framing).

6. Run the Electrical Cable

If Tapping from an Existing Outlet:

  1. Remove the cover plate and outlet from the existing box.
  2. Knock out one of the punch-out holes in the box for the new cable.
  3. Drill through studs between the source and new outlet location.
  4. Feed the cable from the existing outlet to the new box location.

Pro Tip: Use wire staples to secure the cable every 4–6 feet, following code requirements.

7. Wire the New Outlet

  1. Strip about 6 inches of insulation from the outer jacket of the cable.
  2. Strip 3/4 inch of insulation from each conductor (black, white, and ground).
  3. Connect the black (hot) wire to the brass terminal on the new outlet.
  4. Connect the white (neutral) wire to the silver terminal.
  5. Connect the bare copper (ground) wire to the green grounding screw.
  6. Carefully fold the wires into the box and secure the outlet with mounting screws.

8. Connect at the Source Outlet

  1. At the original outlet, connect the new cable’s black wire to the same brass terminal as the existing black wire (or use the second screw if available).
  2. Connect the new white wire to the silver terminal.
  3. Connect the ground wire to the ground screw or splice with existing grounds using a wire nut.

9. Install Covers and Restore Power

  • Install cover plates on both outlets.
  • Turn the breaker back on.
  • Test the new outlet with a voltage tester or plug in a device to ensure proper operation.

Common Mistakes to Avoid

  1. Mistake: Overloading a circuit.
    Solution: Check the existing circuit’s amperage and load before adding an outlet.
  2. Mistake: Skipping ground connections.
    Solution: Always connect the ground wire—it’s essential for safety.
  3. Mistake: Running cable without protection.
    Solution: Use staples, conduit, or approved protection methods per code.
  4. Mistake: Using the wrong wire size.
    Solution: Match wire gauge to circuit amperage (12-gauge for 20-amp, 14-gauge for 15-amp).
  5. Mistake: Not turning off the power.
    Solution: Always shut off the breaker and test for voltage before starting work.

Extra Garage Tips & Hacks

  • Use GFCI Outlets: In most areas, garage outlets must be GFCI-protected for safety.
  • Add Multiple Outlets at Once: If you’re already running cable, consider adding more than one outlet for future needs.
  • Plan for Dedicated Circuits: If you use heavy-duty tools, dedicate a circuit to prevent tripping breakers.

For related upgrades, see our guide on How to Add Motion Sensor Lights to Your Garage to combine power access with automated lighting.

Conclusion

Adding an additional outlet in your garage can dramatically improve convenience, safety, and functionality. By planning carefully, using the correct materials, and following electrical safety practices, you can complete this project efficiently and in compliance with local codes.

Final Tip: Always check local building and electrical codes before starting—some areas require permits or professional installation for new outlets.

CTA: Bookmark this guide for your next garage improvement project and enjoy a safer, more efficient workspace with accessible power exactly where you need it.