Step-by-step: wiring a garage outlet

Plan the circuit before you pull wire

Garage receptacles fall under NEC 210.52(G)(1): at least one 125V, 15A or 20A receptacle in each vehicle bay, not more than 5.5 feet above the floor. That outlet must be on a dedicated 20A branch circuit per NEC 210.11(C)(4), serving only the garage and any accessory buildings... no interior rooms, no exterior receptacles sharing the run unless they meet the exceptions.

Walk the space first. Note panel location, stud bays, existing boxes, and where the vehicle actually parks. A receptacle behind a tool chest is dead copper. Confirm the panel has an open 20A slot and enough neutral and ground terminations before you commit to a home run.

Verify the service type. A bonded neutral panel handles this straightforward. A subpanel with separated neutrals and grounds changes your landing, and a shared neutral on a multiwire branch requires a handle tie per NEC 210.4(B).

Materials and tool check

Garages see moisture, dust, and impact. Spec the install for the environment, not the minimum. 12 AWG copper is the floor for a 20A circuit. Use THHN/THWN-2 in conduit or 12-2 NM-B where concealed in framing and permitted by local amendment.

• 20A single-pole breaker, matched to panel brand (no classified breakers unless UL-listed for that panel)
• 12-2 NM-B with ground, or 12 AWG THHN in EMT for exposed runs
• 20A TR/WR duplex receptacle, spec grade minimum
• GFCI protection: either a GFCI receptacle at the first box or a GFCI breaker
• 4x4 metal box with mud ring for exposed block walls, or a 20 cu in plastic box in framing
• Cable staples, anti-short bushings, wire nuts rated for 12 AWG, and a weatherproof in-use cover if the location qualifies as damp or wet

Confirm torque specs on your breaker and device. Lug torque failures are the top finding in AFCI/GFCI nuisance trip calls. A calibrated screwdriver beats feel every time.

GFCI and AFCI requirements

NEC 210.8(A)(2) requires GFCI protection for all 125V through 250V receptacles, 150V or less to ground, up to 50A, installed in garages. No exceptions for dedicated appliance outlets since the 2020 cycle. If the garage receptacle also serves as a readily accessible outlet for a nearby outdoor location, it still needs GFCI.

AFCI is not required in garages per NEC 210.12, which limits AFCI to dwelling unit kitchens, family rooms, bedrooms, and similar living spaces. Dual-function breakers are fine if the homeowner wants them, but you are not obligated to install one.

Tip: if you are running a single circuit that feeds both a garage receptacle and an exterior receptacle, a 2-pole GFCI breaker at the panel is cleaner than chaining GFCI receptacles. One reset location, one test button, no confused homeowners hunting for a tripped device behind a chest freezer.

Run the cable and set the box

Mount the box at a working height. Code minimum is 15 inches to center for new work per NEC 404.8 guidance for accessibility, but most electricians set garage receptacles at 42 to 48 inches to clear workbenches and keep the outlet above typical flood lines. Confirm the 5.5 foot maximum for the vehicle bay receptacle.

Secure NM cable within 12 inches of a single-gang plastic box or 8 inches of a box without internal clamps, then every 4.5 feet along the run per NEC 334.30. In exposed locations subject to physical damage, switch to EMT or MC. NM is not rated for surface mounting on a garage wall where it can get smacked by a ladder.

1. De-energize the panel and verify with a meter, not a tester pen alone
2. Pull the home run from panel to the first garage box, leaving 8 to 10 inches of free conductor at each opening per NEC 300.14
3. Strip the jacket back so at least 1/4 inch of sheath enters the box
4. Land the grounds first, then neutral, then hot at the device
5. Torque all terminations to the device label spec, typically 12 in-lb for back-wire and 16 to 20 in-lb for screw terminals

Make up the device and terminate at the panel

Back-wire or side-wire, but never back-stab a 20A device. Back-stab terminals are rated for 15A and they loosen under garage temperature swings. Pigtail the receptacle if the circuit continues downstream so pulling the device does not break continuity to the rest of the run, consistent with NEC 300.13(B) for grounded conductors on multiwire circuits and good practice on any shared run.

At the panel, land the equipment ground on the ground bar, the neutral on the neutral bar (or ground bar in a bonded main panel), and the hot on the breaker lug. If you are using a GFCI breaker, the circuit neutral lands on the breaker's neutral lug and the breaker's pigtail lands on the neutral bar. Swap those and the breaker trips the instant you energize it.

Test, label, and close up

Energize and test under load. A plug-in tester confirms polarity and ground, but it does not prove GFCI performance. Use the test button on the device or a dedicated GFCI tester that injects a real fault current. Trip time should be well under 100 ms on a healthy device.

Tip: log the breaker number, circuit description, and install date on the panel directory the same day. Coming back in two years to troubleshoot a nuisance trip is easier when the directory says "Garage recep, bay 2, GFCI breaker, 04/2026" instead of "Garage."

Button up the box, install the cover or in-use bubble cover where required, and confirm the receptacle is TR and WR rated if the location is damp. Snap a photo of the finished work and the panel directory before you leave. That documentation closes the loop on the job and protects you if something changes downstream.