Copper has been used in electrical wiring since the invention of the electromagnet and the telegraph in the 1820s.[1][2] The invention of the telephone in 1876 created further demand for copper wire as an electrical conductor.[3]Copper is the electrical conductor in many categories of electrical wiring.[3][4] Copper wire is used in power generation, power transmission, powerdistribution, telecommunications, electronics circuitry, and countless types of electrical equipment.[5] Copper and its alloys are also used to make electrical contacts. Electrical wiring in buildings is the most important market for the copper industry.[6] Roughly half of all copper mined is used to manufacture electrical wire and cable conductors