Electrical wiring is made of copper wire 200m long and 10mm2. What is her resistance?

| April 21, 2021 | education

Electrical wiring is made of copper wire 200m long and 10mm2. What is her resistance? What is the cross-section of the aluminum wire that must be selected so that its resistance is the same?

1 task) Given: l (length of copper wire for electrical wiring) = 200 m; S (section) = 10 mm2; ρm (specific electrical resistance of copper; t = 20 ºC) = 0.017 Ohm * mm2 / m.

Electrical wiring resistance: R = ρm * l / S = 0.017 * 200/10 = 0.34 Ohm.

Answer: The resistance of copper electrical wiring is 0.34 ohm.

2 task) Given: R (resistance of aluminum wiring) = 0.34 Ohm; l (length of aluminum wire) = 200 m; ρa (specific electrical resistance of aluminum; t = 20 ºC) = 0.028 Ohm * mm2 / m.

Required cross-section of aluminum wire: S = ρa * l / R = 0.028 * 200 / 0.34 = 16.47 mm2.

Answer: The selected aluminum wire will have a cross-sectional area of ​​16.47 mm2.



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