AWG Wire Data Reference

• 1.5–2.5 A/mm² — Continuous duty, enclosed transformers, limited cooling
• 2.5–4 A/mm² — Intermittent duty or well-ventilated designs
• 4–6 A/mm² — Short duty cycle, forced air cooling

Example: 20 AWG wire (0.518 mm²) at 2.5 A/mm² = 1.3 A max

Higher current density increases I²R losses and temperature rise. For audio chokes with DC bias, stay conservative (2–3 A/mm²) to minimize winding temperature.

Single Build (Grade 1): Minimum insulation thickness per NEMA MW1000. Suitable for most hand-wound inductors and transformers.

Heavy Build (Grade 2): Approximately 1.5× the insulation thickness of single build. Better for layer-wound coils where turn-to-turn voltage stress is higher.

Common Insulation Types:

• Polyurethane (155°C): Solderable, good for prototyping
• Polyurethane-Nylon (155°C): Solderable with better abrasion resistance
• Polyester-imide (180°C): Higher temperature, requires stripping
• Polyimide (220°C): Highest temperature rating

American Wire Gauge uses a geometric progression where every 6 gauge decrease doubles the wire diameter, and every 3 gauge decrease doubles the cross-sectional area (halving resistance).