Basic Electrical Installation Work

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51 50 0.30 3.557 – 25 1.44 10 4.07 35 1.5 24. this case the factor 1.114 1. Ω.41 2.877 – 25 1.5 14.40 35 0.5 10.78 35 1.91 16 4.66 16 1.674 2. given Table the Site Guide.91 10 3.5 16.51 2.87 35 1.5 7.1 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 18.20 and therefore the cable resistance under fault conditions will be: 0 585 702 .5 12.83 10 6.524 0.49 6 7.5 19.454 2.20 2.71 4 2.911 1. .16 10 1.51 2.20 1.774 1.74 50 0.22 6 3.048 1.28 Reproduced from the IEE Site Guide kind permission the Institution Electrical Engineers.10 1 36.15 1.10 1.02 4 9.23 – 16 2. .98 – 16 2.387 0.69 6 6. Ω The total earth fault loop impedance therefore: ZS 702 202 .5 1.82 4 4.5 2.82 25 0.5 12.84 50 0.61 4 1.5 25.5 1.08 6 2.251 2.20 1.727 1.20 25 2.64 50 1.Overcurrent, short circuit and earth fault protection 249 Table 12.5 30