An advantage of use of copper is in addition to their high conductivity, has the advantage of being resistant to underground corrosion. Copper is cathodic with respect to other metals that are likely to be burried in the vicinity.
Disadvantages of use of copper are,
a. Grid of copper forms a galvanic cell with burried steel structures, pipes and any of the lead based alloys that might be present in cable sheaths, it is likely be hasten the corrosion of the latter.
b. Use of tinned copper conductor accelerates and concentrates the natural corrosion of metal in small area however cell potential with respect to steel and zinc reduces by about 50% and practically eliminates this potential with respect to lead.