Question

3. Explain the pros and cons of using aluminum wires instead of copper (4 points) 4. Compare the EMT and RMC raceways. When is RMC required? (3 points) 5. Calculate the voltage drop between a distribution panel supplying 120 V to an electrical device that is 200 ft. away from the panel (one circuit - one phase) if the amperage is current = 15 A and copper wires of AWG 14 are used. What is the Voltage available at this device? If this device, requires minimum 110 volt to operate, what can be done (you need to show simple calculation to prove your point) (8 points).

Answer 1

(1) Pros. / Advantage → (a) cost & In international market cost of Copper is nearly 3 times, cost of aluminium. This makes aluminium more Preferable over copper where huge amount of conductor is being used like High voltage electricity transmission, (b) Weight Conductor material required - for same current transfer is nearly 1.85 time les for aluminium compare to copper. That result in low weight Busbar/ conductor which reduce the strength required for the support structure as well as lower transportation cost. (6) Lower corona loss Transmission lines which are subjected to corona loss due to their operating voltage or surrounding environment, large coas action of conductor is required / desirable to reduce its (corona power loss) effect. As aluminium is having lower conductivity compare to copper large cross action conductor

has to be use to match its conductivity as of Copper. This large cross action helps in redusing corona power loss. (d) chemically chemically aluminium shows extremely good resistance against corrosion compare to copper, oxide form on aluminium (Aluminium oxide) is more protective compare to copper. @ Pisad vantage - (a) Conductivity Conductivity of aluminium is - nearly 0.61 times of copper. it means resistivity of aluminium conductor will be more than that of copper. (b) Heat losses As the resistivity of aluminium is high it produces more Heat loss (I²R) losses. This result in reduced efficiency of equipment as well as overheating of equipment. (C) Voltage drop Due to more resistance per unit length compare to copper, aluminium conductor is higher Voltage drop in