Running power to a detached shed involves more than choosing the right wire size. The feeder must be correctly sized for the load and distance, suitable for underground installation, buried at the required depth, and connected to a properly grounded shed subpanel.

This guide covers the complete setup for a typical detached shed 100 to 200 feet from the house with a 60- to 100-amp feeder, including wire sizing, voltage drop, burial, grounding, and panel requirements.

This guide covers the whole chain. It is written for the most common project we see: a detached shed 100 to 200 feet from the house, fed at 60 to 100 amps.

Quick answer: To run electricity to a shed, install a 240V feeder from a 2-pole breaker in the main panel to a subpanel in the shed. Use wet-rated conductors (UF-B, URD, mobile home feeder, or THWN-2/XHHW-2 in conduit), bury them at NEC Table 300.5 depth, run four wires (two hots, neutral, ground), keep neutral and ground separated in the shed panel, and drive a grounding electrode at the shed. Size the wire for both ampacity and voltage drop. A small shed with lights and a couple of receptacles can instead use a single 20-amp GFCI-protected branch circuit.

NEC references in this article follow the 2023 edition. Confirm the edition your jurisdiction enforces before you buy materials.

Step 1: Decide How Much Power the Shed Needs

The choice of the cable for the shed depends on the expected load. Start here.

NEC 225.30 allows a detached building to be supplied by only one feeder or branch circuit. That rule answers a question we hear often: "Can I run two 20-amp circuits to my shed?" Not as two separate circuits. You can run one multiwire branch circuit (which counts as one circuit under 225.30), or run a feeder to a subpanel and split circuits inside the shed. For most sheds with any real use, the subpanel is the better choice. It lets you add more circuits or electrical loads later without digging a second trench.

Shed Wiring Diagram: How Power Moves From the House to the Shed

A code-compliant shed electrical installation follows this path:

1. Main panel: a 2-pole breaker sized to the feeder conductors.

2. Feeder: two hots, one neutral, one equipment grounding conductor (EGC).

3. Exit from the house: conductors protected in the raceway from the enclosure down to the trench, per NEC 300.5(D)(1).

4. Trench: direct burial cable or conduit at Table 300.5 depth.

5. Riser at the shed: conduit from the trench up to the shed panel. Use Schedule 80 PVC wherever the riser is exposed to damage (NEC 352.10(F)).

6. Shed subpanel with a main breaker: this serves as the building disconnect required by NEC 225.31 and 225.32.

7. Inside the shed panel: neutral bar isolated from the enclosure, ground bar bonded to it. Remove the bonding screw or strap (NEC 250.32(B)(1)).

8. Grounding electrode system: a grounding electrode conductor from the shed panel ground bar to ground rods (NEC 250.32(A)). Two rods at least 6 feet apart are the common approach (NEC 250.53(A)(2) and (A)(3)).

9. Branch circuits: lights and receptacles, with GFCI protection on 125V through 250V receptacles in the accessory building (NEC 210.8(A)).

Wire Size for a Shed: Amps and Distance

Shed wire size depends on both ampacity and voltage drop, especially on long runs.

The table below shows the minimum conductor size that passes both tests. Assumptions: 240V single-phase, 75°C-rated wet-location conductors (THWN-2, XHHW-2, USE-2, URD) on 75°C terminations, full breaker load, and a 3% maximum voltage drop per the informational notes to NEC 215.2(A). Use the 75°C ampacity column for conductors terminated on 75°C-rated breakers and panel lugs, even when the wire insulation is rated 90°C.

Note: UF-B ampacity is limited by its 60°C rating. Shed feeders also do not qualify for the dwelling sizing allowance in NEC 310.12; size them using Table 310.16.

Cables Used to Wire a Shed

Underground wiring is considered a wet location, including wiring inside conduit. Use wet-location-rated conductors; avoid cable types that are not approved for underground or wet-location use.

UF-B Underground Feeder Cable

UF-B is copper, direct burial rated, sunlight resistant, and simple to terminate. It is the most common choice for a shed. The 60°C ampacity limit and copper price make it best for shorter runs and smaller loads. Under NEC 240.4(B), 6/3 UF-B (55 amps) can be protected by a 60-amp breaker when it feeds a subpanel.

Shop 6/3 UF-B Stranded Copper Underground Feeder Cable

THWN-2 and XHHW-2 Single Conductors in Conduit

Individual conductors in PVC give you the most flexibility. You choose the exact size for each conductor, you can pull out and upsize later without a new trench, and conduit only needs 18 inches of cover. THWN-2 copper and XHHW-2 aluminum are both wet rated. Keep total bends between pull points at 360° or less (NEC 352.26).

Shop THWN-2 building wire · Shop XHHW-2 aluminum

Aluminum Mobile Home Feeder (2-2-2-4 and 2-2-4-6)

A mobile home feeder is a four-conductor aluminium cable with two hots, a neutral, and a ground. It is direct-burial-rated and can be a cost-effective choice for long shed runs.

Note: For a shed feeder, 2-2-2-4 aluminum cable must be protected by a 90A breaker, even when connected to a 100A-rated subpanel. A full 100A feeder requires larger conductors.

Which 2-2-2-4 Cable For a Shed?

• 2-2-2-4 Aluminum Mobile Home Feeder: the standard pick for a shed feeder.

• Shop 2-2-2-4 Aluminum Mobile Home Feeder Cable

• Dyke 2-2-2-4 Aluminium URD: also direct-burial rated with XLPE insulation. It works well when the jacket carries a USE-2 marking, and the fourth conductor is re-identified as the ground at each end.

A 2-2-2-4 SER cable is a different product and does not belong in the trench at any point.

Aluminum URD Quadruplex and Triplex

URD (underground residential distribution) cable is designed for utility secondaries, and its XLPE insulation performs well in direct burial. Quadruplex styles, such as Tulsa 4-4-4-4 and Dyke 2-2-2-4, provide all four conductors for a shed feeder. A triplex URD has only three conductors, so a shed feeder with 120V loads also requires a separate equipment-grounding conductor in the trench if you choose to use it.

Shop Aluminum URD Cable

NM-B (Romex): Inside the Shed Only

NM-B is for dry locations. It cannot go underground or in an underground conduit because that raceway is a wet location. Inside a dry shed, NM-B works for branch circuits. Protect it wherever it is exposed to damage, which in an unfinished shed usually means running it in conduit or behind a finished surface.

SER Cable: Not for Underground Runs

We regularly get questions like "Can I run SER in conduit to my shed?" The answer for the underground portion is no. NEC 338.12(A)(2) prohibits SE cable underground, with or without a raceway. SER is a good choice above ground, for example from a meter to a panel or along an interior wall, but the buried section needs one of the wet-rated options above.

How to Run Power to a Shed, Step by Step

1. Pull a permit and call 811. Most jurisdictions require a permit for a new feeder. Call 811 at least a few business days before you dig so utility lines get marked.

2. Choose direct burial or conduit. NEC Table 300.5 sets minimum cover depth:

24 in. — Direct-burial cable (UF-B, URD, MHF).

18 in. — PVC conduit listed for direct burial.

6 in. — Rigid metal conduit or IMC.

12 in. — 120V residential branch circuit, 20A maximum, with GFCI protection.

A shallower trench is cheaper to dig, which is why many DIYers put direct burial cable inside PVC anyway. Warning tape 12 inches above the cable is inexpensive and worth it. Where frost heave is a concern, provide slack or expansion fittings at the risers (NEC 300.5(J)).

3. Protect the conductors where they leave the ground. NEC 300.5(D)(1) requires raceway protection from the trench up to the enclosure or at least 8 feet above grade.

4. Pick and pull the cable. Match the conductor size to the table above and the cable type to your trench.

5. Set up the shed panel. Install a subpanel with a main breaker serving as the building disconnect at the nearest point of entrance (NEC 225.32). Separate neutral and ground, and connect the ground bar to the grounding electrodes. The one exception to the electrode requirement is a shed fed by a single branch circuit that includes an equipment grounding conductor (NEC 250.32(A) Exception).

6. Wire the inside. Install GFCI-protected receptacles per NEC 210.8(A). Any shed receptacle outdoors must be weather-resistant and housed in a cover that remains weatherproof while in use (NEC 406.9).

7. Arrange an inspection before backfilling. The inspector may need to verify the burial depth and wiring method while the trench is still open.

The Cheapest Code-Compliant Way to Wire a Shed

DIYers tell us cost matters, and it should. The cheapest option that still passes inspection depends on the load:

• Light use (lights plus a few receptacles): a single 20-amp, 120V circuit in 12/2 UF-B is the lowest-cost route. With GFCI protection at the house end (a GFCI breaker or a GFCI receptacle where the circuit starts), the cable only needs 12 inches of cover. Past about 100 feet, voltage drop calls for heavier cable: 10/2 UF-B to about 150 feet, 8/2 to about 240 feet, and 6/2 at 300 feet. At that point, a small 240V subpanel usually costs less and performs better. Shop 12/2 UF-B Underground Feeder Cable

• 30A to 60A over 100 feet: aluminum usually beats copper. A 4-4-4-4 aluminum URD quadruplex often costs less per foot than 8/3 copper UF-B and carries more current. Check the breaker lug range first: many 30-amp breakers will not accept 4 AWG conductors, so match the breaker to both the wire and the panel.

• 60A to 100A: aluminum mobile home feeder or URD quadruplex is almost always the least expensive direct burial option.

Note: When powering multiple outbuildings, you can run separate feeders from the main panel or feed a second building from the first building’s subpanel, provided the upstream feeder is sized for the combined loads. Each detached building generally requires its own disconnect and grounding electrode system.

Why Shed Wiring Fails Inspection

Most shed wiring failures have little to do with feeder size. Inspectors more often flag these issues:

• Neutral bonded to ground in the shed panel.

• Missing grounding electrode system at the shed.

• Wrong cable used underground, such as NM-B or SER.

• Insufficient burial depth or missing riser protection.

• No disconnect at the shed, or one that is not readily accessible.

• Missing GFCI protection on shed receptacles.

Less common but still important: upsized conductors may require a larger equipment grounding conductor, and large aluminum conductors must fit the breaker lugs listed for them.

Your Shed Wiring Questions, Answered

These are real questions our team has received from customers wiring sheds, lightly edited. Unless a question says otherwise, the answers assume a 240V single-phase feeder, 75°C terminations, and voltage drop held to about 3% at the stated load.

Which Cable Should I Buy?

I'm running 100 amps to my shed about 110 feet away. What is the proper name of the copper wire I need?

For copper in conduit, ask for THHN/THWN-2 copper building wire: three 3 AWG conductors (two hots and a neutral) and one 8 AWG equipment ground. At 110 feet and 100 amps, 3 AWG copper keeps voltage drop near 2%. Buy dual-rated THHN/THWN-2 rather than plain THHN, because the inside of an underground conduit is a wet location (NEC 300.5(B)).

What type of cable, and how many conductors, do I need for a 100-amp service to a shed 130 feet away?

Four conductors: two hots, a neutral, and an equipment ground. In conduit, that means 3 AWG copper or 1 AWG aluminum for the hots and neutral, with an 8 AWG copper or 6 AWG aluminum ground (NEC Table 250.122). Both sizes stay under 3% voltage drop at 130 feet.

I'm running 135 feet of 1-1/2 inch PVC with one 90° and one 45° bend, on a 60-amp breaker, with #2 aluminum. Should I use THHN/THWN single conductors or aluminum mobile home feeders?

Both work. Single conductors pull more easily through conduit with bends, and your 135° of total bends is well under the 360° limit in NEC 352.26. The mobile home feeder is twisted and stiffer, but it is direct-burial rated, so the conduit provides extra protection rather than a requirement. #2 aluminium is larger than the 60 amps required, which is good for voltage drop. Because the hots are upsized, NEC 250.122(B) requires a proportionally larger ground: the 4 AWG ground in the 2-2-2-4 mobile home feeder covers that requirement. If you choose copper singles instead, 4 AWG copper is enough at this distance.

I'm going 150 feet from my house to a 60-amp shed panel. What wiring do I need, and do you also sell breaker panels?

At 150 feet and 60 amps, use 4 AWG copper or 2 AWG aluminum. Aluminum mobile home feeder (2-2-4-6 or 2-2-2-4) is the most cost-effective direct burial choice at this distance. Contact our team about panels and breakers for the project.

Can I Use SER Cable?

Can 4-4-4-6 aluminum SER be directly buried? What do you have that's 4-4-4-6 direct burial for 170 feet to a 60-amp shed with a 220-volt air compressor?

SER cannot be buried. At 170 feet and 60 amps, 4 AWG aluminum reaches about 4.3% voltage drop, which is too high with a compressor starting on the line. 2-2-2-4 aluminum mobile home feeder or 2-2-2-4 aluminum URD keeps drop under 3%. Add the compressor's full-load current to your load calculation before you choose the breaker.

What Size Wire for My Distance?

I want to run 50 feet of wire in underground conduit to a 60-amp shed subpanel. What do you recommend?

6 AWG copper THWN-2 or 4 AWG aluminum XHHW-2 for the hots and neutral, with a 10 AWG copper or 8 AWG aluminum ground. 1-inch PVC gives you an easy pull. 6/3 UF-B in conduit also works on a 60-amp feeder breaker under NEC 240.4(B).

I need a feeder from my main panel to a shed subpanel, buried, 60 feet at 100 amps. Is this wire good for that?

At 60 feet, ampacity sets the size: 3 AWG copper or 1 AWG aluminum, with an 8 AWG copper or 6 AWG aluminum ground. Any wet-rated conductor type works in conduit. For direct burial, use a cable rated for it.

Can I use 6/3 UF-B for about 100 feet to a shed home office panel?

Yes. 6/3 UF-B is rated 55 amps and can feed a subpanel on a 60-amp breaker (NEC 240.4(B)). At 100 feet, voltage drop stays around 2.5% even at full load.

I'm looking for 180 feet of #6 quadruplex for a 40-amp shed panel, direct burial.

At 180 feet and 40 amps, 6 AWG aluminum drops close to 5%. Step up to 4-4-4-4 aluminum URD quadruplex, which holds the drop near 3% at 40 amps.

I'm going 200 feet underground to a pre-wired shed with a few lights, maybe four receptacles, and a 120V mini split. I'm comparing 6/3 UF-B, 8/3 UF-B, and 6 AWG THHN in conduit.

Skip 8/3 UF-B: at 200 feet it drops close to 4% at 30 amps. 6/3 UF-B on a 40-amp feeder keeps the drop around 2.5% at a 30-amp load. 6 AWG copper singles in conduit perform about the same, provided you buy dual-rated THHN/THWN-2. For the lowest cost, 4-4-4-4 aluminum URD handles this load easily.

Long Runs

I need 300 feet of wire for a 20-amp shed circuit in conduit.

At 300 feet on 120V, 12 AWG copper drops about 16% at a 16-amp load, which is far too much. 6 AWG copper reduces the drop by about 4%, and you splice down to 12 AWG in a junction box before the receptacles. At this distance, a 240V feeder to a small subpanel is usually less expensive and performs better.

I need to run power to a shed 400 feet from my house. Regular 120V, possibly 240V, possibly 100 amps.

Distance drives the cost here. A full 100-amp feeder at 400 feet needs 3/0 copper or 250 kcmil aluminum. At 60 amps, 3/0 aluminum works. At 30 amps, 1 AWG aluminum works. Calculate the shed's real load first, because the difference in cable cost between 30 and 100 amps at this distance is substantial.

Circuits, Services, and Bigger Projects

I'm running a 60-amp breaker to a shed 107 feet away with 2 AWG aluminum XHHW-2 in buried conduit, but it didn't pass inspection. Which wire do I need?

The wire size is almost certainly not the problem: 2 AWG aluminum carries 90 amps and drops under 2% at this distance. Instead, you may have issues with a bonded neutral in the shed panel, a missing ground rod, a ground that was not upsized along with the hots, or conductors too large for the breaker lug. Ask the inspector for the specific violation before buying new wire.

Frequently Asked Questions

What size wire do I need to run 100 amps to a shed 150 feet away?

2 AWG copper or 1/0 aluminum holds voltage drop to 3% at full load. 1 AWG aluminum meets ampacity for 100 amps but runs slightly over 3% at that distance under full load.

How deep do I bury wire to a shed?

24 inches for direct burial cable, 18 inches for PVC conduit, 6 inches for rigid metal conduit, and 12 inches for a GFCI-protected 120V, 20A residential branch circuit (NEC Table 300.5).

Do I need a ground rod at my shed?

Yes, when the shed is fed by a feeder to a subpanel (NEC 250.32(A)). A shed fed by a single branch circuit with an equipment grounding conductor is exempt.

Do I need a permit to run power to a shed?

In most U.S. jurisdictions, yes. Check with your local building department before you dig.

Nassau National Cable stocks UF-B underground feeder cable,aluminum mobile home feeder, aluminum URD quadruplex and triplex, and THWN-2 and XHHW-2 building wire, cut to the length you need. Send us your amperage and run distance, and our team will confirm the conductor size and cable type before you order.