R
Conductor Resistance
R1+R2 values at 20°C and temperature correction factors from BS 7671 Appendix I.
R1+R2 at 20°C — Table I1
R1+R2 at 20°C — Table I1
| Line (mm²) | CPC (mm²) | R1 (mΩ/m) | R2 (mΩ/m) | R1+R2 (mΩ/m) |
|---|---|---|---|---|
| 1.0 | 1.0 | 18.10 | 18.10 | 36.20 |
| 1.5 | 1.0 | 12.10 | 18.10 | 30.20 |
| 2.5 | 1.5 | 7.41 | 12.10 | 19.51 |
| 4.0 | 1.5 | 4.61 | 12.10 | 16.71 |
| 6.0 | 2.5 | 3.08 | 7.41 | 10.49 |
| 10.0 | 4.0 | 1.83 | 4.61 | 6.44 |
| 16.0 | 6.0 | 1.15 | 3.08 | 4.23 |
BS 7671: Table I1
Temperature Correction
R1+R2 at Operating Temperature
Rₜ = R₂₀ × [1 + 0.004 × (t - 20)]
Rₜ Resistance at temperature t (Ω)
R₂₀ Resistance at 20°C (Ω)
t Operating temperature (°C)
For PVC insulated cables at 70°C, the multiplier is 1.20. Simplified: R₇₀ = R₂₀ × 1.20
BS 7671: Appendix I
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