16 mm² copper is rated about 85 A installed per Method C (clipped direct, 70 °C thermoplastic) and drops 2.8 mV/A/m (single-phase figure, matching BS 7671 Appendix 4 within rounding). The chart shows how far it runs before the drop exceeds the limits.
| Load | 230 V @ 3% | 230 V @ 5% | 400 V 3Ø @ 5% |
|---|---|---|---|
| 6 A | 409 m | 681 m | 1369 m |
| 10 A | 245 m | 409 m | 821 m |
| 16 A | 153 m | 256 m | 513 m |
| 20 A | 123 m | 204 m | 411 m |
| 32 A | 77 m | 128 m | 257 m |
| 40 A | 61 m | 102 m | 205 m |
| 63 A | 39 m | 65 m | 130 m |
Computed with ρ ≈ 0.0225 Ω·mm²/m (copper at operating temperature), matching BS 7671 Appendix 4 mV/A/m values within rounding. Grouping, insulation type and installation method change the amp rating — treat 85 A as the Method C reference figure.
The nearest equal-or-larger AWG size is 4 AWG — see the gauge converter for exact areas.
About 85 A for copper clipped direct (Method C). Enclosed in conduit in insulation it derates substantially — always check the installation method column in BS 7671 Appendix 4.