Running electricity to a detached garage, shed, workshop, or other outdoor structure requires a dedicated circuit from your main panel, wiring that meets outdoor and underground code requirements, and proper grounding and protection at the structure. This is work for a licensed electrician — not because it’s impossibly complex, but because the code requirements are specific, the consequences of errors include fire and electrocution, and unpermitted work creates problems when you sell your home. Done!’s licensed Colorado electricians handle outdoor structure wiring routinely and pull the required permits.

Starting at the Main Panel

Every outdoor structure circuit originates at your home’s main electrical panel. The electrician evaluates whether the panel has capacity for additional circuits — both available breaker slots and available amperage. Older homes throughout the Denver metro that still have 100-amp service may be at or near capacity, particularly if electric vehicle charging, heat pumps, or other modern loads have been added. If the panel is full or undersized, a panel upgrade or subpanel installation may be part of the project scope.

The size of the circuit depends entirely on what the structure will be used for. A basic shed with a few lights and one outlet needs far less capacity than a workshop running 240-volt power tools or a garage with an EV charger. Done! sizes the circuit for your intended use — and for a reasonable degree of future flexibility — so you’re not back in two years upgrading an undersized run.

Underground vs. Overhead Runs

The two main methods for getting power from your house to the structure are underground (buried conduit or direct-burial cable) and overhead (aerial cable between structures). Underground runs are more common in residential settings and cleaner in appearance. The required burial depth depends on the wiring method:

  • Rigid metal conduit (RMC) or intermediate metal conduit (IMC) — 6 inches minimum depth
  • PVC conduit — 18 inches minimum depth
  • Direct-burial cable (UF-B) without conduit — 24 inches minimum depth

Colorado’s expansive clay soils shift significantly with freeze-thaw cycles, which is one reason conduit is often preferred over direct-burial cable — the conduit protects the wire from soil movement and makes future wire replacement possible without digging. Your Done! electrician will recommend the method best suited to your yard conditions and the distance of the run.

Overhead runs using triplex cable (service entrance cable) are an option when trenching is impractical, but clearance requirements are strict — minimum 10 feet above grade in pedestrian areas, 12 feet where vehicles may pass, and 18 feet over driveways. Most residential applications where a trench is feasible opt for underground to avoid the clearance limitations and aesthetic impact.

The Subpanel at the Structure

If the structure needs more than one or two circuits — which is typical for a workshop, finished garage, or home office — a small subpanel is installed at the structure. The subpanel receives power from the main panel feed and distributes it to the individual circuits inside the building. This gives you room to grow: adding lighting, outlets, a dedicated circuit for a compressor, or a 240-volt circuit for a welder or EV charger later doesn’t require running a new feed from the house each time.

The subpanel must be properly grounded and bonded at the structure. This is a code-specific requirement that differs from how grounding works at the main panel, and it’s one area where DIY installations frequently have errors that create shock hazards.

GFCI Protection, Weatherproof Covers, and Permits

All outdoor outlets must be GFCI-protected and housed in weatherproof in-use covers. Interior outlets in an unheated detached structure are also typically required to be GFCI-protected under current NEC code. Done!’s electricians install the correct protection throughout and ensure covers meet the in-use weatherproof standard — not just covers that snap shut when nothing is plugged in.

Permits are required for this work in virtually every Colorado jurisdiction. A permit means an inspector verifies the installation meets code before the trench is backfilled and the work is closed in — protecting you, future buyers, and your homeowner’s insurance coverage.

Learn more about what Done!’s team handles on our panels and wiring page and installations and remodels page. If you’re adding an EV charger to the structure, visit our EV charging page. Contact Done! to schedule a free estimate.