A direct current (DC) distribution circuit made with copper conductors is 2km long per distributor. Each one of the conductors has a diameter of 10mm and is suitable to carry 50A. The current carrying capacity must however be increased to 200A per conductor. Calculate the diameter of an aluminium conductor, which can be connected in parallel with copper conductor. Take the resistivity of copper to be 0.017ohm per meter and that of aluminium to be 0.028ohm per meter.