What Size Wire for a Microwave?
Wire and breaker sizing for a Microwave — the typical 120V circuit, plus the code details (NEC 310.16) that change the answer.
Calculations are built on the 2023 National Electrical Code (NEC) and cross-checked against the published code tables. How we verify. Last reviewed June 2026.
On a 20A 120V circuit at 75°C terminations.
Protected by a 20A breaker (NEC 240.6).
GFCI required. The 2023 NEC (210.8(D) for specific appliances, 210.8(A) for kitchen/outdoor receptacles) requires GFCI protection here. Verify the code edition your jurisdiction has adopted.
Microwave Circuit Details
- Countertop and over-the-range microwaves use a dedicated 120V 20A circuit (12 AWG).
- A typical 1,000–1,200W microwave draws 10–13A.
- A dedicated circuit prevents nuisance trips when other kitchen loads run.
Long run to your microwave?
Over distance, voltage drop can require a larger wire than the table above. See the 20A wire size by distance:
Size it for your exact install
Open the calculator pre-filled with 20A at 120V to add distance, material and temperature.