➰ Wire Size

Selecting the Right Wire Size (AWG)

Choosing the correct wire gauge is critical for safety. A wire that is too thin (too high gauge) for the current flow will overheat, potentially melting insulation and causing a fire.

Ampacity Guide (Copper Wire)

Approximate max current for common household wiring (NM cable):

• 14 AWG: 15 Amps (Lightning circuits)
• 12 AWG: 20 Amps (Outlets, Appliances)
• 10 AWG: 30 Amps (Water heaters, ACs)
• 8 AWG: 40 Amps (Electric Ranges)
• 6 AWG: 55 Amps (Subpanels, Large motors)

Factors to Consider

1. Load Current: The maximum amps the device will draw.
2. Distance: Long runs require larger wire to prevent voltage drop.
3. Temperature: Hotter environments reduce the wire's capacity to carry current.
4. Conduit Fill: Bundling many wires together generates heat, requiring de-rating.

FAQ

What does AWG mean?

AWG stands for American Wire Gauge. Note that the system is inverse: a larger number means a thinner wire (e.g., 18 AWG is much thinner than 10 AWG).