Shed Wiring Guide: Running Power from House to Outbuilding

Running electricity to a detached shed opens up a world of possibilities — power tools, task lighting, electric lawn equipment charging, and even climate control. While shed wiring is one of the more accessible electrical projects for DIY homeowners in many jurisdictions, it still requires permits, correct wire sizing, and proper grounding. This guide covers everything you need to know.

Planning Your Circuit Needs

Before running wire, inventory what you’ll power in the shed. Basic lighting and a few outlets for hand tools can be handled by a 20-amp, 120V circuit. A dedicated workshop with table saw, air compressor, and dust collector may need a 60-amp subpanel with multiple circuits. Plan for more capacity than you think you need — adding more later means digging up the yard again.

Subpanel vs Single Circuit

For a single 20-amp circuit, run 12/2 direct-burial cable from an existing breaker in the house panel (or a new breaker) to the shed. For multiple circuits or future expansion, install a small subpanel (60-100 amp) in the shed and run appropriate feeder cable from the main house panel. A 60-amp subpanel feeder requires 6 AWG copper or 4 AWG aluminum, while a 100-amp feeder requires 4 AWG copper or 2 AWG aluminum.

Underground vs Overhead Cable

Underground feeder (UF-B) cable is the most common choice for residential outbuildings. Burial depth requirements: 12 inches for 120V circuits in conduit, 24 inches for direct-burial UF cable at 120/240V. Overhead service entrance cable is an alternative — it must maintain 10 feet of clearance over pedestrian areas and 12 feet over driveways. Call 811 (Dig Safe) before digging to locate underground utilities.

Grounding at the Shed

Detached buildings must have their own grounding electrode — typically two 8-foot ground rods driven into the earth at the shed. This local grounding provides protection even if the grounding conductor from the house is broken. The neutral and ground buses are kept separate in the shed subpanel (bonded only at the main house panel).

Inside the Shed

Wire the shed interior as you would any room. Use weather-resistant outlets in damp areas, GFCIs near utility sinks or exterior walls, and provide adequate lighting. If the shed isn’t insulated, use outdoor-rated fixtures. A service disconnect (breaker or disconnect switch) at the shed provides a local shutoff for the entire subpanel.

Size your shed feeder correctly. Use the Wire Size Calculator on electricalcalcpro.com to verify the correct conductor size for your shed’s subpanel feeder based on amperage and run distance.