American Wire Gauge (AWG): What is the diameter in mils (thousandths of an inch) of 22-AWG copper wire?

Introduction / Context:
Technicians frequently convert between American Wire Gauge (AWG) and physical diameter for connector selection, current-carrying capacity, and estimating resistance per length. Mils (0.001 inch) provide a convenient imperial measure of small diameters.

Given Data / Assumptions:

• Standard AWG system (Brown & Sharpe).
• Requested size: 22 AWG copper wire.
• 1 mil = 0.001 inch.

Concept / Approach:

AWG sizes follow a logarithmic relation: diameter d(n) in inches = 0.005 inch * 92^((36 − n)/39). While this formula is exact, many practitioners memorize common sizes (e.g., 20 AWG ≈ 0.0320 in, 22 AWG ≈ 0.0253 in, 24 AWG ≈ 0.0201 in). Converting inches to mils multiplies by 1000.

Step-by-Step Solution:

Verification / Alternative check:

Use the AWG formula: d(22) = 0.005 × 92^((36 − 22)/39) ≈ 0.0253 in. Tables in handbooks corroborate 22 AWG ≈ 0.0253 in (25.3 mils), cross-sectional area ≈ 642 circular mils.

Why Other Options Are Wrong:

• 10.03 mils: far too small (closer to ~30 AWG).
• 22.35 mils: somewhat smaller than true; not the standard value.
• 45.26 and 71.96 mils: much larger; correspond to far lower gauge numbers (thicker wires).

Common Pitfalls:

• Confusing circular mil area with diameter in mils; they are different quantities.
• Mixing SWG (Standard Wire Gauge) with AWG, which yields different diameters.

Final Answer:

25.30 mils