( V_drop = \frac\sqrt3 \times L \times I \times R_c1000 ) For exact cable sizing, refer to AS/NZS 3008.1.1:2017 – Electrical installations – Selection of cables . Summary Table for Quick Reference | Installation part | Max drop | Voltage (230V system) | |---|---|---| | Consumer mains | 2% | 4.6V | | Subcircuit | 3% | 6.9V | | Total | 5% | 11.5V |