Wire Size Tables & Dimensions

Comprehensive wire size tables with cross-sectional areas for all common AWG and MCM conductors. These dimensions are essential for accurate conduit fill calculations and NEC compliance.

📏 Measurement Note

All areas shown include insulation thickness for THWN-2 conductors, the most common wire type for conduit installations.

AWG Wire Sizes (14 AWG - 4/0 AWG)

Wire Size Bare Conductor
Area (sq in)
THWN-2
Area (sq in)
THHN
Area (sq in)
Common Uses
14 AWG 0.0041 0.0097 0.0097 15A circuits, lighting
12 AWG 0.0066 0.0133 0.0133 20A circuits, outlets
10 AWG 0.0105 0.0211 0.0211 30A circuits, A/C units
8 AWG 0.0166 0.0366 0.0366 40A circuits, electric ranges
6 AWG 0.0264 0.0507 0.0507 55A circuits, water heaters
4 AWG 0.0419 0.0824 0.0824 70A circuits, feeders
3 AWG 0.0528 0.0973 0.0973 85A circuits
2 AWG 0.0665 0.1158 0.1158 95A circuits
1 AWG 0.0839 0.1562 0.1562 110A circuits
1/0 AWG 0.1057 0.1855 0.1855 125A circuits
2/0 AWG 0.1333 0.2223 0.2223 145A circuits
3/0 AWG 0.1681 0.2679 0.2679 165A circuits
4/0 AWG 0.2120 0.3237 0.3237 195A circuits

MCM Wire Sizes (250 MCM - 2000 MCM)

Wire Size Bare Conductor
Area (sq in)
THWN-2
Area (sq in)
THHN
Area (sq in)
Ampacity (75°C)
250 MCM 0.1963 0.3904 0.3904 215A
300 MCM 0.2356 0.4536 0.4536 240A
350 MCM 0.2749 0.5242 0.5242 260A
400 MCM 0.3142 0.5863 0.5863 280A
500 MCM 0.3927 0.7073 0.7073 320A
600 MCM 0.4712 0.8316 0.8316 350A
700 MCM 0.5497 0.9453 0.9453 385A
750 MCM 0.5890 0.9887 0.9887 400A
1000 MCM 0.7854 1.2667 1.2667 455A
1250 MCM 0.9817 1.5482 1.5482 495A
1500 MCM 1.1781 1.8289 1.8289 525A
2000 MCM 1.5708 2.3479 2.3479 590A

Insulation Type Comparison

THWN-2 (Thermoplastic Heat & Moisture Resistant)

  • 90°C dry locations, 75°C wet locations
  • Most common for conduit installations
  • Nylon jacket provides durability
  • Excellent pulling characteristics

THHN (Thermoplastic High Heat Resistant)

  • 90°C dry locations only
  • Slightly smaller diameter than THWN-2
  • More conductors possible in same conduit
  • Requires separate moisture protection

Quick Reference Guide

🏠 Residential Common Sizes

  • 14 AWG: 15A lighting circuits
  • 12 AWG: 20A outlet circuits
  • 10 AWG: 30A appliance circuits
  • 8 AWG: 40A electric range
  • 6 AWG: 50A water heater

🏢 Commercial Common Sizes

  • 4 AWG: 70A feeders
  • 2 AWG: 95A feeders
  • 1/0 AWG: 125A feeders
  • 4/0 AWG: 195A feeders
  • 250 MCM: 215A feeders

⚡ Service Entrance

  • 2/0 AWG: 100A service
  • 4/0 AWG: 200A service
  • 250 MCM: 200A+ service
  • 350 MCM: 260A service
  • 500 MCM: 320A service

© 2024 Conduit Fill Calculator. All rights reserved.

Professional electrical conduit fill calculations per NEC standards

© 2024 Conduit Fill Calculator. All rights reserved.

Professional electrical conduit fill calculations per NEC standards