How to Add an Outdoor Electrical Outlet: GFCI-Protected Exterior Outlet Installation (2026)

Frequently Asked Questions

Does an outdoor outlet need to be GFCI protected?

Yes. The National Electrical Code (NEC) requires all outdoor receptacles to be GFCI-protected. This can be accomplished two ways: (1) Install a GFCI outlet at the outdoor location — it protects itself and anything downstream. (2) Connect the outdoor outlet to the LOAD terminals of an indoor GFCI outlet — the GFCI upstream provides protection. Either approach is code-compliant. Never install a standard (non-GFCI) outlet outdoors.

What kind of cover does an outdoor outlet need?

Two types of weatherproof covers exist: (1) In-use covers (bubble covers) — these stay closed while a plug is inserted, protecting the connection from rain. Required by current NEC code for any outdoor outlet that may be used in wet conditions. (2) Flip covers — they protect an empty outlet but not one with a plug. Only compliant for outlets in a dry protected location (covered porch with no rain exposure). For most outdoor applications: in-use bubble cover is required. The cover and box are usually sold together.

Can I tap an existing outdoor outlet to add another one?

Yes, if the circuit has enough capacity. Check the existing outlet: is it already on a 20-amp circuit? (Look at the breaker.) Adding another outlet means adding load capacity — confirm total load on the circuit stays under 80% of the breaker rating (16 amps for a 20-amp breaker). If the outdoor outlet is the last outlet on a GFCI circuit, you can add to it. If tapping from the back of an existing outdoor GFCI: use the LOAD terminals on the GFCI to protect the new outlet, or install a new GFCI at the new location.

What wire type do I use for outdoor wiring?

For wiring through walls and conduit: THWN wire is rated for wet locations and can run inside conduit. For direct burial (running cable in the ground): use UF-B cable (Underground Feeder) — it's rated for direct burial without conduit. For surface-mounted conduit: use EMT or PVC conduit with THWN wire. For running through the wall from an indoor outlet to an outdoor box: standard NM-B (Romex) cable is acceptable when run through the wall cavity only — it cannot be exposed to the exterior. Check local code, as some jurisdictions require conduit for all outdoor wiring.

Do I need a permit to add an outdoor outlet?

Most jurisdictions require a permit for new outlet installation, even a single outlet. Cost is usually $25–$75 for a simple electrical permit. The permit process ensures an inspector verifies the work meets code. If you sell the house, unpermitted electrical work can complicate the sale. In practice, many homeowners add single outlets without permits — but getting the permit is the correct approach. Contact your local building department for requirements.

How do I run underground wiring to a shed, detached garage, or landscape lights?

Two code-compliant options: (1) UF-B cable (Underground Feeder) — bury at least 18 inches deep per NEC 300.5, or 12 inches if you lay a layer of concrete or add a plastic warning tape above the cable. (2) THWN wire inside rigid PVC conduit (Schedule 40 or 80) — only needs 12 inches of burial depth, and conduit makes it easier to pull new wire later without digging. Conduit is almost always the better long-term choice: run 3/4-inch or 1-inch PVC now so you can add circuits later without digging again. For a detached garage or shed with actual tools and loads, run a dedicated 20-amp circuit from its own breaker — a shared circuit will trip constantly.

Can I install an outdoor outlet myself or should I hire an electrician?

You can legally DIY outdoor outlet installation in most U.S. states with a homeowner-pulled permit — check your state since California, Oregon, and a few others restrict unlicensed electrical work even by homeowners. The skills required: identify the source circuit and verify breaker amperage, run cable safely through walls or conduit, connect GFCI wiring correctly (LINE vs LOAD terminals matter), and weatherproof the exterior box. If you're not comfortable with any of those steps, hire a licensed electrician — outdoor circuits and panel work are where DIY electrical errors cause fires and shock hazards. A single outdoor outlet typically costs $150–$300 professionally installed, which is reasonable for the confidence it buys.

Outdoor outlets must be GFCI-protected (or on a GFCI-protected circuit) and covered by a weatherproof in-use cover (a bubble cover that fits over a plug while it’s inserted). The simplest installation: tap an existing interior outlet on an outside wall, drill through the wall, and install a new GFCI outlet in an exterior weatherproof box.

Adding an outdoor outlet is straightforward when tapping an interior outlet on the same wall — mostly drilling and weatherproofing.

What you need

• GFCI outlet, 20-amp ($15–$25)
• Weatherproof in-use outlet cover with box ($15–$30)
• NM-B 12/2 cable (or 14/2 if tapping a 15-amp circuit)
• 1/2-inch drill bit and long drill bit for wall penetration
• Wire staples
• Non-contact voltage tester
• Weatherproof exterior caulk

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Step 1: Choose the tap location

Find an indoor outlet on an exterior wall. Turn it off at the breaker and verify power is off with a non-contact tester. Pull the outlet from the box and look for available space in the box — you need room for the additional wires.

Alternatively, install a new junction at the panel (requires a licensed electrician if adding a new circuit breaker).

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Step 2: Plan the exterior outlet location

Directly on the opposite side of the wall from the interior outlet is ideal — minimizes the hole length. Mark the spot on the exterior. Check what’s inside the wall cavity at that location: use a stud finder, and drill a small exploratory hole to confirm no obstructions (insulation is fine; blocking studs are not).

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Step 3: Drill through the wall

Drill a 1-inch hole through the exterior wall at the outlet location. Angle the drill slightly downward (toward the exterior) — this prevents water from running into the wall along the cable. Feed the cable through the hole from inside.

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Step 4: Mount the weatherproof box

The exterior weatherproof box mounts over the hole. Apply a bead of exterior caulk around the back edge of the box before screwing it to the siding. This seals the gap between box and siding. Feed the cable through the box’s cable knockouts using a weatherproof cable clamp.

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Step 5: Wire the GFCI outlet

At the outdoor box: strip cable and wires. Connect:

• Black (hot) → LINE or LOAD terminal (black/brass screw)
• White (neutral) → LINE or LOAD terminal (silver screw)
• Bare copper → green ground screw

If this is a GFCI outlet: use LINE terminals (the outlet itself provides GFCI protection). If connecting to the LOAD terminals of an upstream GFCI: use LOAD terminals and remove the “TEST/RESET” label on the receptacle face.

At the indoor outlet: connect the new cable to the existing outlet’s terminals as pigtails or directly. The indoor outlet must have a ground.

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Step 6: Seal and test

Fold wires into the exterior box. Mount the GFCI outlet. Install the weatherproof in-use cover per its instructions (most snap or screw onto the box).

Caulk around the cable entry point where it enters the exterior wall — inside and out.

Restore power. Press the TEST button on the GFCI, then RESET. Test with a plug-in tester or lamp.

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Related guides

• How to Replace an Electrical Outlet — outlet replacement basics
• How to Fix a Tripping GFCI Outlet — troubleshooting GFCI trips after installation
• How to Add an Electrical Outlet — adding interior outlets from existing circuits
• Best Home Security Cameras — top camera picks to power from your new outdoor outlet