While current is the starting point, several environmental and installation factors modify the required size:
The selection process generally follows a logical sequence: cable sizes
| ❌ Mistake | ✅ Correct | |------------|------------| | Using speaker wire for mains power | Use approved power cable (e.g., H05VV-F, THHN, TPS) | | Ignoring voltage drop on long extension leads | Use heavier gauge for 50m runs | | Matching cable only to plug/socket rating | Check actual load current and breaker size | | Bundling many cables tightly without derating | Leave space or use larger cable | | Using aluminium cable without knowing its lower capacity | Aluminium needs ~1.6× larger mm² than copper | While current is the starting point, several environmental
A 2.5 mm² cable carries more current safely than a 1.0 mm² cable. While current is the starting point