Basic Electrical Installation Work

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49 6 7.10 1.66 16 1.5 25.02 4 9.454 2.91 10 3.5 12.07 35 1.98 – 16 2.911 1.40 35 0.5 1.28 Reproduced from the IEE Site Guide kind permission the Institution Electrical Engineers. Ω The total earth fault loop impedance therefore: ZS 702 202 .84 50 0.20 and therefore the cable resistance under fault conditions will be: 0 585 702 .Overcurrent, short circuit and earth fault protection 249 Table 12.877 – 25 1.674 2.64 50 1.51 2.524 0.69 6 6.5 7.51 50 0.5 12.1 Table the IEE Site Guide: Value Resistance/Metre for Copper and Aluminium Conductors and per Metre 20°C in Milliohms/Metre Cross-sectional area (mm2 ) Resistance/metre (R1 R2)/ metre (mΩ/m) Phase conductor Protective conductor Copper Aluminium 1 18.727 1.82 25 0.16 10 1.10 1 36.557 – 25 1.71 4 2.5 10.5 30. this case the factor 1.5 2.41 2.20 1.22 6 3.5 14.23 – 16 2.251 2.91 16 4.774 1.5 1.20 25 2.20 1.114 1. Ω.08 6 2.44 10 4.83 10 6.5 24.15 1.387 0.20 2.61 4 1.78 35 1.87 35 1.82 4 4.5 19.5 16. .51 2.74 50 0.048 1. given Table the Site Guide. .30 3