Changes

Copper is used in electrical engineering mostly because of its high electricalconductivity which with 58 MS/m (or m/Ωmm²) is only slightly below that ofsilver. Other advantages of copper are its high thermal conductivity, corrosionresistance, and its good ductility. The work hardening properties of ETP copper is illustrated in <xr id="fig:StrainHardening" />. The increase in strength achieved by cold working can be reversed easily by subsequent annealing. The softening properties arestrongly dependent on the preceding cold working percentage''(<xr id="fig:SofteningOfCu"/> and 5.3)''.

The purity of technically pure and un-alloyed copper used for electricalapplications depends on the type used and ranges between > 99.90 and 99.95wt%. The copper types are designated mainly by their oxygen content asoxygen containing, oxygen-free, and de-oxidized with phosphorus asdescribed in DIN EN 1652 ''(<xr id="tab:MaterialDesignations"/> and 5.2)''.Tables 5.3. and 5.4 show thephysical and mechanical properties of these copper materials. According tothese, Cu-ETP, Cu-OFE, and Cu-HCP are the types of copper for whichminimum values for the electrical conductivity are guaranteed.Cu-ETP is less suitable for welding or for brazing in reducing atmosphere

*) As units for electrical conductivity MS/m and m/Ω.mm² are commonly used. Frequently – and mostly in North America – the % IACS value (International Annealed Copper Standard) is also used, where 100% is equivalent to 58 MS/m or m/Ωmm² .For the description of mechanical strength properties the units of N/mm² or MPa are most commonly used: 1 MS/m = 1 m/Ωmm² 1 MPa = 1 N/mm²