12 AWG Wire Ampacity

The workhorse of residential wiring - required for 20-amp kitchen, bathroom, and garage circuits.

12 AWG Quick Specifications

25A
Copper Ampacity
20A
Aluminum Ampacity
3.31
mm² Area
2.053
mm Diameter

Complete 12 AWG Specifications

Wire Gauge 12 AWG
Diameter (inches) 0.0808 in
Diameter (mm) 2.053 mm
Cross-sectional Area 3.31 mm² (6,530 circular mils)
Copper Resistance 5.211 Ω/1000ft (17.09 Ω/km) @ 20°C
Copper Ampacity (60°C) 20A
Copper Ampacity (75°C) 25A
Copper Ampacity (90°C) 30A
Max Circuit Breaker 20A (per NEC)

Common Applications for 12 AWG Wire

Kitchen Circuits

Required for kitchen small appliance circuits serving countertop outlets. NEC mandates minimum two 20A circuits.

Bathroom Circuits

Required for bathroom outlets. Each bathroom needs at least one 20A circuit for hair dryers and other appliances.

Garage Outlets

Garage and workshop outlets require 20A circuits to handle power tools and equipment.

Laundry Circuits

Laundry room outlets for washing machines require dedicated 20A circuits with 12 AWG wire.

Outdoor Outlets

Outdoor receptacles for lawn equipment, holiday lights, and general outdoor use.

Dedicated Appliances

Microwave ovens, garbage disposals, and dishwashers often require dedicated 20A circuits.

12 AWG vs 14 AWG: Which to Use?

Feature 12 AWG 14 AWG
Max Circuit Breaker 20A 15A
Copper Ampacity 25A 20A
Voltage Drop (50ft, 10A) 1.6V (1.3%) 2.5V (2.1%)
Cost (per 250ft) ~$80-120 ~$50-80
Required For Kitchen, bath, garage, laundry General lighting only

Pro Tip: Many electricians use 12 AWG throughout the home for future flexibility. The slightly higher cost is offset by the ability to upgrade any circuit to 20A without rewiring.

NEC Requirements for 12 AWG

  • Maximum Overcurrent Protection: 20 amps per NEC 240.4(D)
  • Required For: Kitchen countertop circuits (minimum 2), bathroom circuits, laundry circuits, garage circuits per NEC 210.11
  • GFCI Protection: Required in kitchens, bathrooms, garages, outdoors, and within 6 feet of sinks
  • Voltage Drop: NEC recommends maximum 3% for branch circuits

12 AWG Voltage Drop Calculator

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