Cable Sizing & AWG: The Complete Guide for Australian Installers
American Wire Gauge (AWG) is the standard system for measuring the diameter of electrical wires. While Australia officially uses the metric system (mm and mm²), AWG appears constantly in real installs because most networking cable, imported electronics, and audio gear is specified in AWG rather than metric units.
This section gives you everything you need to convert between AWG and metric, calculate cable specifications, and select the right size for your installation.
The Key Concept: AWG is Backwards
The most important thing to remember about AWG: the higher the number, the thinner the wire. A 24 AWG wire is thinner than a 14 AWG wire. This is counterintuitive but consistent. The number reflects how many times the wire was drawn through dies during manufacturing to reduce its diameter.
The scale is also logarithmic, not linear, which means simple rules of thumb apply:
- A change of 3 AWG approximately doubles or halves the electrical resistance
- A change of 6 AWG approximately doubles or halves the wire's diameter
- A change of 10 AWG changes resistance by a factor of approximately 10
Quick Reference: Common Australian Cable Sizes
| Cable Type | AWG | Diameter (mm) | Area (mm²) |
|---|---|---|---|
| Cat5e network cable | 24 AWG | 0.51 | 0.21 |
| Cat6 / Cat6A network cable | 23 AWG | 0.57 | 0.26 |
| Slim Cat6 patch leads | 28 AWG | 0.32 | 0.08 |
| Security/alarm cable | 22 AWG | 0.64 | 0.33 |
| Speaker cable (light) | 18 AWG | 1.02 | 0.82 |
| Speaker cable (heavy) | 14 AWG | 1.63 | 2.08 |
| Mains extension lead | 14-12 AWG | 1.63-2.05 | 2.08-3.31 |
AWG Calculators & Conversion Tools
Use these tools to convert between AWG and metric, or to calculate specific cable dimensions:
- AWG Overview - what AWG is, why it matters in Australia, and key rules of thumb for quick mental conversions
- AWG to mm Conversion (by Diameter) - find AWG from a known diameter in millimetres, or vice versa
- AWG to mm² Conversion (by Area) - find AWG from a known cross-sectional area in mm²
- AWG Calculator for Stranded Wire - find equivalent AWG for multi-strand cable using the 3-step formula
- How to Calculate Cable Area - step-by-step formulas for cross-sectional area of solid and stranded wire
- How to Calculate Cable Diameter - find the overall diameter of stranded cable bundles
- AWG Reference Table - complete specifications including weight (kg/km) and DC resistance (Ω/km)
Why Cable Sizing Actually Matters
The right cable size isn't just a spec sheet detail. It directly affects:
- Voltage drop: Critical for PoE installs where cameras and access points fail intermittently when voltage drops below their operating threshold
- Current-carrying capacity: Australian standard AS/NZS 3008 specifies maximum current ratings based on conductor area in mm²
- Conduit fill: AS/NZS 3000 limits how many cables fit in a conduit based on overall diameter
- Bend radius: Minimum bend radius is typically 4-8x the cable diameter for data cable
- Compliance: Wrong cable size in a regulated installation can fail certification and create liability
For specific Cat6 vs Cat6A sizing decisions, see our Cat6 vs Cat6A guide. For ensuring you're not buying non-compliant cable, see our guide to the dangers of CCA cable.
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