Chart Australia: Cable Size

While you must use the chart, here is a general guide for standard domestic circuits (assuming a short run and enclosed in a wall):

For the licensed electrician, the cable size chart is a legal document. For the homeowner, it’s a warning: never downsize a cable to save $20 . In Australia’s harsh climate, the copper is cheap—the fire is expensive. cable size chart australia

Always refer to the latest for copper cables, and when in doubt, go up a size. The 6.0mm² you install today is a problem you will never have tomorrow. While you must use the chart, here is

15 Amps. Step 2: Apply derating. Roof insulation (Method C, buried) = factor 0.57. 15A / 0.57 = 26.3A required capacity. Step 3: Look at chart. A 2.5mm² cable is rated 20A (too small). A 4.0mm² is rated 32A (sufficient for 26.3A). Step 4: Check voltage drop. Using the chart, 4.0mm² over 45m at 15A yields a drop of roughly 2.8% (acceptable). Conclusion: You need 4.0mm² TPS, not 2.5mm². Always refer to the latest for copper cables,