What Size Breaker for Microwave?
A microwave requires a 20A breaker with 12 AWG wire on a 120V dedicated circuit.
🔌 Wire Length & Voltage Drop Check
Microwave Wiring Guide — NEC Requirements
Built-in and over-the-range microwaves should have a dedicated 20A/120V circuit. Countertop microwaves can use a shared kitchen small-appliance circuit.
Pro Tip
💡 NEC 210.52 requires at least two 20A small-appliance circuits in the kitchen. A microwave can use one of these.
Why a 20A Breaker?
The microwave draws approximately 12A at 120V (1500W). A 20A breaker provides adequate protection.
Wire Sizing per NEC 310.16
For a 20A/120V circuit, 12 AWG copper is required per NEC Table 310.16 at 75°C. For runs over 75 feet, upsize to 12 AWG. Use our Wire Size Calculator and Voltage Drop Calculator.
Complete Parts List
To wire a microwave circuit: a 20A single-pole breaker, 12 AWG NM-B cable (Romex) for interior runs or THHN/THWN-2 in conduit for exposed runs, a NEMA 5-15 or 5-20 receptacle, cable clamps, and appropriate junction boxes.
Disclaimer: This guide is for reference only. All electrical work must be performed by or verified by a licensed electrician. Local codes may differ from NEC.