Basic Electrical Installation Work

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5 12.5 10.20 1.20 1. given Table the Site Guide.66 16 1.91 10 3.20 25 2.557 – 25 1.524 0.51 2.87 35 1.114 1.02 4 9.877 – 25 1. .5 25.40 35 0.674 2.30 3.69 6 6. this case the factor 1. Ω The total earth fault loop impedance therefore: ZS 702 202 .51 50 0.82 25 0.44 10 4.74 50 0.5 19.Overcurrent, short circuit and earth fault protection 249 Table 12.20 2.251 2.78 35 1.5 24.727 1.774 1.23 – 16 2.41 2.5 16.15 1.20 and therefore the cable resistance under fault conditions will be: 0 585 702 .387 0.71 4 2.64 50 1.51 2. .28 Reproduced from the IEE Site Guide kind permission the Institution Electrical Engineers.10 1 36.5 7.84 50 0.10 1.91 16 4.5 12.454 2.16 10 1.5 1.1 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 18.5 2.5 1.83 10 6.5 14.22 6 3.49 6 7.82 4 4.048 1.61 4 1.98 – 16 2.5 30. Ω.07 35 1.08 6 2.911 1