Garage Electrical Wiring: Wire Selection and Code Requirements
Garage wiring is one of the most rewarding electrical projects because a properly wired garage dramatically increases its utility as a workshop, home gym, EV charging station, or hobby space. The NEC has specific requirements for garage electrical that differ from standard living space wiring, primarily around GFCI protection and circuit capacity. Here is a complete guide to wiring a garage correctly.
NEC Requirements for Garage Outlets
The NEC requires at least one 20-amp outlet circuit in an attached garage, and all garage receptacles must be GFCI-protected per Section 210.8(A)(2). This means no 15-amp circuits for garage outlets, and no bypassing the GFCI requirement. The GFCI requirement applies to all 125-volt, 15-amp, and 20-amp receptacles in garages, including those in finished garage spaces used as workshops or hobby rooms. A single 20-amp circuit with GFCI protection satisfies the minimum code requirement, but most garages benefit from multiple circuits.
Outlet Circuits: 12/2 NM-B or 12/2 MC Cable
All garage outlet circuits use 12/2 cable on 20-amp breakers. For an attached garage where the wiring runs concealed in finished walls or through framing, 12/2 NM-B is standard. For exposed garage wall and ceiling runs (the most common garage installation where studs are exposed and wiring is visible), 12/2 MC cable provides the physical protection required when NM-B is not hidden within wall cavities. MC cable snaps into metal outlet boxes with MC connectors and runs cleanly along exposed framing without requiring conduit. Plan for one outlet approximately every 6 to 8 feet around the garage perimeter to avoid extension cord dependency.
Lighting Circuit: 14/2 NM-B
Garage lighting typically runs on a dedicated 15-amp circuit using 14/2 NM-B. LED shop lights draw minimal amperage (typically less than 2 amps per 4-foot fixture), so a single 15-amp circuit can supply 10 to 15 LED shop lights without approaching the circuit capacity. Run 14/2 from the panel to the first light fixture, then continue the circuit from fixture to fixture. Three-way switch wiring (to control garage lights from both the house door and the garage door) uses 14/3 NM-B between the two switch locations.
EV Charger Circuit: 10/2 NM-B
A 30-amp Level 2 EV charger requires a dedicated 240-volt circuit using 10/2 NM-B on a 30-amp double-pole breaker. This circuit runs from the panel directly to the EV charger location and serves only the charger. If you anticipate upgrading to a 40-amp charger in the future, run 8/2 NM-B now and install a 40-amp breaker: the marginal cost of 8 AWG versus 10 AWG wire at installation is far less than replacing wire in a finished wall later.
Workshop Tools: 12/2 NM-B on Multiple Circuits
A serious workshop with table saws, compressors, dust collectors, and other motor loads benefits from multiple dedicated circuits. Each high-draw tool should ideally have its own 20-amp circuit with 12/2 NM-B to prevent nuisance tripping when two tools run simultaneously. A workshop subpanel with 4 to 8 circuits is the cleanest solution for a fully equipped shop, eliminating long wire runs from the main panel and providing expansion capacity as the shop grows.
Detached Garage: Underground Feed
A detached garage requires an underground feeder from the main house panel. Options include 12/2 UF-B direct burial for simple single-circuit feeds (minimum 24-inch burial depth), individual THHN conductors in Schedule 40 PVC conduit for multi-circuit feeds (minimum 12-inch burial depth when in conduit), or SER cable in conduit for subpanel feeds of 60 amps or larger. The detached garage must also have its own grounding electrode system (ground rods) and an isolated neutral bar per NEC Article 225.
IB Lighting carries 12/2 MC cable, 12/2 and 14/2 NM-B, 10/2 NM-B for EV charger circuits, 12/2 UF-B for underground feeds, and THHN in all standard gauges. Free freight insurance on every order. Browse our wire and cable selection or call (800) 674-9019 for a full garage wiring package quote. We also carry Generac standby generators for garages that need backup power.