Calculate the earth loop impedance
A load, 100 m from a 415 V Supply Authority point is connected by a35 mm2 pvc/swa/pvc copper cable. The current rating is 119 A and thevolt drop per ampere metre is 1.1 mV. If the load current is 90 A,determine whether the volt drop at the load is within the 17th Edition ofthe IEE Wiring Regulations 5% limit. Using TABLE 1, calculate theearth loop impedance, minimum fault current (neglect the supply/earthimpedance) and select an appropriate fuse for the circuit with reference toB.S. 88 part 2 (see FIGURE 3, Lesson 4 – 4).

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