Not as a permanent solution — and in many cases not even as an acceptable long-term temporary one. Running an extension cord to a detached shed or garage might work in a pinch for a single tool, but it’s not safe or code-compliant for ongoing use. The right answer is a dedicated electrical circuit or subpanel installed by a licensed electrician, and Done can handle that installation correctly, to code, and with the proper permits.

Why Extension Cords Are the Wrong Tool for This Job

Extension cords are designed for temporary use, not continuous or semi-permanent power supply. Running one to an outbuilding creates several real hazards:

  • Fire risk from overloading: Extension cords have current ratings far lower than what you’d draw with multiple tools, lighting, and a refrigerator running in a garage. An overloaded cord generates heat that can start a fire in an enclosed space
  • No GFCI protection: Outdoor and garage circuits are required by code to have GFCI protection. A standard extension cord provides none
  • Damage from exposure: Cords run through doors, windows, or along the ground degrade from UV exposure, pinching, moisture, and temperature cycling — Colorado’s wide seasonal swings accelerate this breakdown
  • Trip and damage hazard: Cords crossing driveways or walking paths create trip hazards and get damaged by vehicle tires and foot traffic
  • Voltage drop: Long extension cord runs reduce the voltage reaching your tools, which can damage motor-driven equipment over time

The Right Solution: A Dedicated Circuit or Subpanel

For a detached garage or shed, the correct approach is running a dedicated circuit from your home’s main panel — typically underground in conduit — to either an outlet box or a small subpanel in the outbuilding. The installation includes proper grounding, GFCI protection, and the ampacity to handle what you actually plan to run in the space.

A subpanel is the right choice if you want multiple circuits in the outbuilding — separate circuits for lighting, outlets, and potentially a 240V circuit for a welder, compressor, or EV charger. Done sizes the feeder and subpanel based on your anticipated load, not just the minimum that’s technically legal.

Permits and Code Requirements

Running power to a detached structure requires a permit in most Colorado jurisdictions, and the installation must be inspected before the trench is backfilled. The underground portion typically requires a minimum burial depth and the wiring method must meet local code. Done pulls the permit, does the work correctly, and coordinates the inspection so you’re left with a code-compliant installation and a closed permit, not a liability.

What the Project Typically Involves

Done starts with an assessment of your main panel to confirm it has capacity for the additional circuit or feeder. From there, we plan the underground route, install conduit and appropriate wiring, mount and connect the outlet box or subpanel in the outbuilding, and test the entire installation. Done provides an upfront estimate so you know what the project will cost before work begins.

Adding EV Charging or 240V Circuits to the Mix

If you park a vehicle in your garage, this is the ideal time to add a 240V circuit for an EV charger or a Level 2 charging outlet. Running the underground feeder once and sizing it correctly from the start is far more economical than returning later to upgrade. Done installs EV charging circuits as part of garage electrical projects and can combine the work efficiently into a single project.

For any detached structure electrical project, visit our panels and wiring page or our electrical installations page to learn more. Contact Done to schedule an assessment — we serve the Denver metro and Front Range with licensed electrical work and proper permitting.