How to Run Electricity to a Shed: Wiring, Trenching and Permits

An extension cord snaking across the lawn is how most backyard power projects start, and it is also how many of them end in a tripped breaker, a melted plug, or a mower-shredded cord. A shed with electricity turns a storage box into a usable workshop, potting room, or home office, but getting there safely means planning the load, choosing the right cable and burial method, and pulling a permit. Buried feeders and panel connections carry real shock and fire risk if they are done wrong.

The short version: first figure out how much power you need. A few lights and a couple of outlets can usually run on a single dedicated 120-volt circuit. Power tools, a heater, a window air conditioner, or a well-equipped insulated shed usually calls for a feeder to a small subpanel. Either way, the cable runs underground in an approved wiring method at a depth your local code requires, every receptacle needs GFCI protection, and the work gets inspected before the trench is backfilled.

Many homeowners handle the trenching, conduit, and interior layout themselves and hire a licensed electrician for the panel connections. That split saves money while keeping the highest-risk work in professional hands.

Planning a Shed With Electricity: Estimate Your Load First

Every decision flows from the load. List everything you plan to plug in and add up the wattage. Typical examples:

• LED lighting: 10 to 20 watts per fixture.
• Battery chargers and small tools: 100 to 800 watts.
• Circular saw, miter saw, or table saw: 1,200 to 1,800 watts while running, with higher startup draw.
• Portable electric heater: about 1,500 watts.
• Window or mini-split air conditioner: 500 to 1,500 watts or more.
• Air compressor: 1,000 to 2,000 watts with a significant startup surge.

A 20-amp, 120-volt circuit can supply roughly 1,900 watts of continuous load with a safety margin. If your list includes a heater plus a saw, or an AC unit plus lights and a compressor, you will outgrow a single circuit fast. An insulated shed with electricity and plumbing, such as one with an electric water heater or a small bathroom, almost always needs a subpanel. Plan for what you might add in five years, not just what you own today, because re-trenching later costs far more than upsizing the cable now.

Single Circuit vs Subpanel: Which Setup You Need

A Single Dedicated Circuit

For lights, a few receptacles, and occasional tool use, one 15- or 20-amp circuit from the house panel is the simplest and least expensive option. The circuit is protected by a breaker at the main panel, and the shed typically needs a local disconnect or a switch arrangement that meets your code. It works well for garden sheds, bike storage, and light hobby spaces.

A Feeder and Subpanel

A subpanel gives you multiple circuits in the shed: one for lights, one or two for receptacles, and dedicated circuits for a heater, air conditioner, or 240-volt tool. The feeder is sized to the total load, often 30 to 60 amps for a typical workshop. Outbuilding subpanels usually need their own grounding electrode system, such as ground rods, and the grounds and neutrals must be kept separate in the subpanel. Details like these are exactly why panel work belongs with a licensed electrician.

If you are unsure, err toward a subpanel. A small outdoor subpanel load center with a handful of breaker spaces gives you room to grow, and the incremental cost is modest compared with digging a second trench.

Wiring Methods: UF Cable vs Conduit

You have two common choices for the underground run, and your local code decides which are permitted and how deep each must go.

• Direct-burial UF cable: Underground feeder cable is rated to sit directly in soil. It is the cheapest option but typically requires the deepest trench, and it offers no protection against a future shovel. It must be protected in conduit where it emerges from the ground.
• PVC conduit with individual conductors: Schedule 40 or 80 PVC conduit with wet-rated THWN conductors inside. Conduit usually allows a shallower burial depth, protects the wires, and lets you pull larger or additional wires later. Most electricians prefer this method.
• Rigid metal conduit: The shallowest permitted depth but the most expensive material, used where digging is difficult.

Burial depths commonly range from about 6 inches for rigid metal conduit, to around 18 inches for PVC conduit, to roughly 24 inches for direct-burial cable, with some reductions allowed for GFCI-protected residential branch circuits. Requirements vary by jurisdiction and change with code updates, so confirm the exact depth with your building department before you dig. Use wire gauge matched to the breaker and the run length. Long runs over 100 feet often need a larger conductor to limit voltage drop.

Tools and Materials

• Trenching shovel or rented walk-behind trencher
• PVC conduit, sweeps, couplings, primer and cement, or UF cable
• Wet-rated conductors sized for the circuit
• Weatherproof boxes, in-use covers, and GFCI receptacles or a GFCI breaker
• Subpanel, breakers, and ground rods if running a feeder
• Warning tape to lay in the trench
• Non-contact voltage tester
• Fish tape, wire strippers, and cable staples

Step-by-Step: Running Power to a Shed

1. Pull the permit. Contact your building department, describe the project, and ask about burial depth, GFCI and disconnect requirements, and inspection stages. Most jurisdictions require a trench inspection before backfilling.
2. Call 811. Have public utilities mark buried gas, electric, water, and communication lines at least a few business days before digging. Private lines such as sprinkler pipes or a line to a pool pump will not be marked, so locate those yourself.
3. Plan the route. Choose the shortest practical path from the house exit point to the shed, avoiding tree roots, septic fields, and future garden beds.
4. Dig the trench. Excavate to the required depth plus a couple of inches for a sand bed. Keep the bottom free of sharp rocks.
5. Install conduit or cable. Lay the conduit with sweeping bends at each end, glue joints, and protect exposed vertical runs where the cable enters and exits the ground. Lay warning tape about 12 inches over the conduit as you backfill later.
6. Pass the trench inspection. Leave the trench open until the inspector signs off.
7. Wire the shed interior. Mount boxes, run cable or conduit to lights and receptacles, and install GFCI protection on all receptacles. Use weatherproof boxes with in-use covers on any exterior outlet.
8. Connect at the panels. This is the step to hand to a licensed electrician. Before anyone opens a panel or touches existing wiring, turn off the breaker and confirm power is off with a non-contact voltage tester. Never work on energized conductors.
9. Final inspection and backfill. Backfill in layers, tamp lightly, and schedule the final inspection before putting the circuit into regular use.

GFCI, Grounding and Safety Essentials

Outdoor structures sit on damp ground and host metal tools, which is a risky combination. Code generally requires GFCI protection for receptacles in sheds and other accessory buildings, and exterior receptacles need weatherproof in-use covers. A GFCI breaker at the source protects the entire run; GFCI receptacles protect from the device onward.

Grounding matters just as much. A subpanel in a detached building typically needs a grounding electrode system and a separate equipment ground conductor back to the main panel. Mixing grounds and neutrals in a subpanel can put current on metal surfaces, creating a shock hazard. If any of this sounds unfamiliar, that is a clear signal to bring in a pro.

Whenever you troubleshoot, turn off the breaker and confirm power is off with a non-contact voltage tester before touching any wire or device. If you need to check continuity or resistance, do it only with the power off. Never probe or test energized wiring as a DIY step.

Troubleshooting Shed Power Problems

• GFCI trips repeatedly: moisture in an exterior box, a damaged cable, or a tool with a ground fault. Unplug everything, reset, and add devices back one at a time. Persistent trips with nothing plugged in point to a wiring fault that an electrician should trace.
• Lights dim when a tool starts: voltage drop from undersized wire or a long run. The fix is usually a larger conductor or a subpanel feeder.
• Breaker trips under load: too many devices on one circuit. Spread loads across circuits or upgrade to a subpanel.
• Condensation inside boxes: seal conduit ends entering the shed and use weatherproof boxes outdoors.

Cost to Run Electricity to a Shed

Costs depend on distance, trench conditions, and the setup. A short, single-circuit run with DIY trenching may cost a few hundred dollars in materials. A professionally installed circuit commonly runs from several hundred to a couple thousand dollars. A feeder and subpanel for a workshop or insulated shed typically costs more, often in the low-to-mid thousands, especially for long runs, rocky soil, or a main panel that needs upgrading. Permit fees are usually modest by comparison. Doing your own trenching is one of the easiest ways to cut the bill.

When to Call a Licensed Professional

Hire a licensed electrician for the panel work, including installing breakers in the main panel, setting a subpanel, and establishing the grounding electrode system. You should also call a pro if your main panel is full or older, if the run exceeds 100 feet, if you want 240-volt circuits, or if the shed will include plumbing, heating, or air conditioning. Plumbing lines to an insulated shed should go to a licensed plumber, and any gas line is licensed-pro-only work. Always pull permits and schedule inspections. Unpermitted wiring can void insurance coverage and create problems when you sell your home.