How to run power to a detached garage

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Introduction

A detached garage is a versatile space—it can serve as a workshop, storage area, hobby room, or even a home office. But without electricity, its functionality is limited. Running power to a detached garage allows you to install lighting, operate tools, charge devices, and heat or cool the space. In this guide, you’ll learn how to run power to a detached garage safely and efficiently, from planning to installation.

⚠ Important: This project involves electrical work that may require permits, inspections, and compliance with local building codes. If you’re not experienced with electrical wiring, hire a licensed electrician.

Why Running Power to a Detached Garage Matters

Adding electricity to your garage comes with big advantages:

  • Increases functionality for tools, appliances, and lighting.
  • Boosts property value by creating a more usable space.
  • Improves safety by eliminating the need for temporary extension cords.
  • Allows year-round use with heating, cooling, and lighting.
  • Supports future upgrades like EV charging stations or home offices.

Step-by-Step Guide to Running Power to a Detached Garage

1. Plan Your Electrical Needs

Start by listing what you want to power:

  • Overhead lights and workbench lighting.
  • Standard outlets for tools, chargers, and appliances.
  • 240V circuits for heavy-duty equipment or EV charging.
  • Heating and cooling units.

Pro Tip: Calculate the total amperage required. A small garage may need only a 30–60 amp subpanel, while a larger workshop may require 100 amps.

2. Check Local Codes and Permits

Before starting:

  • Contact your local building department for requirements.
  • Confirm whether underground or overhead wiring is permitted in your area.
  • Find out what type of conduit and wiring is required.
  • Apply for the necessary permits—most areas require inspection before the system is energized.

3. Choose a Power Supply Method

There are two main ways to run electricity to a detached garage:

  • Overhead Wiring
    • Less expensive and easier to install.
    • Requires poles and weatherproof cable.
    • May be limited by local codes.
  • Underground Wiring
    • Safer and more aesthetically pleasing.
    • Protected from weather and accidental damage.
    • Requires trenching and conduit installation.

4. Select the Right Wire and Conduit

  • Wire type: Use UF-B cable for direct burial (without conduit) or THWN wire for conduit installations.
  • Gauge: Match wire gauge to amperage needs (e.g., #6 AWG for 60 amps, #2 AWG for 100 amps).
  • Conduit: PVC conduit is common for underground runs; use rigid metal conduit for added protection if required.

5. Install a Subpanel in the Garage

A subpanel gives you multiple circuits and flexibility for future expansion:

  1. Choose a subpanel rated for the amperage you calculated.
  2. Include enough breaker spaces for lighting, outlets, and special circuits.
  3. Keep neutral and ground wires separate in the subpanel (as required by code).

6. Dig the Trench (for Underground Wiring)

  • Depth requirements: Typically 18–24 inches deep for conduit, 24 inches for direct burial cable (check local code).
  • Safety: Call 811 (in the US) or your local utility locator before digging to avoid hitting buried lines.
  • Lay conduit in the trench and secure it with straps as needed.

7. Run the Wiring

  • From the Main Panel: Turn off power, remove the panel cover, and connect the feeder wires to a double-pole breaker sized for the subpanel amperage.
  • Through the Conduit: Pull the wires from the house to the garage using fish tape or a pull line.
  • Into the Subpanel: Connect hot wires to the main lugs, neutral to the neutral bar, and ground to the ground bar.

8. Wire the Garage Circuits

Inside the garage:

  • Install outlets along walls (GFCI-protected for safety).
  • Add lighting circuits with switches.
  • Use proper wire gauge and breaker sizes for each circuit.

9. Ground the Garage Subpanel

Drive a grounding rod into the earth near the garage and connect it to the subpanel’s ground bar using copper grounding wire. This is often required for detached structures.

10. Test and Inspect

  • Double-check all connections for tightness.
  • Replace all panel covers.
  • Turn on the breaker at the main panel.
  • Test each circuit in the garage for correct operation.
  • Schedule an inspection if required before permanent use.

Common Mistakes to Avoid

  1. Skipping Permits
    • Problem: Could lead to fines or unsafe wiring.
    • Solution: Always check local codes and obtain permits.
  2. Using the Wrong Wire Size
    • Problem: Causes overheating and fire risk.
    • Solution: Match wire gauge to amperage load.
  3. Not Providing GFCI Protection
    • Problem: Increased shock hazard in a garage environment.
    • Solution: Use GFCI outlets or breakers.
  4. Improper Grounding
    • Problem: Can cause electrical faults or unsafe operation.
    • Solution: Install a grounding rod and connect properly.
  5. Underestimating Future Needs
    • Problem: You’ll outgrow your system quickly.
    • Solution: Plan for extra breaker spaces and capacity.

Extra Garage Tips & Hacks

  • Install Conduit Larger Than Needed: Makes it easier to pull additional wires later.
  • Add Dedicated Circuits: For high-draw tools like welders or compressors.
  • Use LED Lighting: Reduces energy use and heat output.
  • Related Tip: Check our guide on how to upgrade your garage electrical panel for more power flexibility.

Conclusion

Learning how to run power to a detached garage gives you the knowledge to plan, design, and oversee a safe, functional electrical system. With the right permits, materials, and installation process, your garage can become a fully powered workspace ready for any project.

Bookmark this guide to keep your garage powered, safe, and future-ready for all your tools and equipment.