Depending on the application there are many grades of Copper. The main application of Copper is due to its properties of Electrical Conductivity. Hence the most important aspect while choosing Copper is its Conductivity and not purity.
In the Indian Market the there are two main grades of copper available----EC grade (ETP grade) and Commercial/industrial grade.
ETP grade Copper is made out of Virgin raw material extracted from the ore itself. Whereas the commercial / industrial grade copper is made by melting scrap.
While melting of scrap, oxidation is inevitable and the conductivity ( efficiency of carrying current) is reduced drastically anywhere between 30% and 70%. This reduction in efficiency cannot be controlled.
In short Commercial Copper carries only 0.3 to 0.7 times the current that ETP Grade Copper can carry.
Thus a smaller cross-section of ETP Copper is sufficient to carry a particular ampearage of current as compared to commercial grade copper thus resulting in monetary savings.
Apart from this there is a faster Dissipation of Current in ETP Copper which is vital for Earthing, lesser heating of system and so on.Variety and a large range of sizes available in ETP Grade Copper ensures flexibility in design and Cost savings.