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→5.1.2 Pure Copper
The purity of technically pure and un-alloyed copper used for electrical applications depends on the type used and ranges between > 99.90 and 99.95
wt%. The copper types are designated mainly by their oxygen content as oxygen containing, oxygen-free, and de-oxidized with phosphorus as
described in DIN EN 1652 ''(<xr id="tab:MaterialDesignations"/> and 5.2)''.Tables 5.3. and 5.4 show the physical and mechanical properties of these copper materials. According to these, Cu-ETP, Cu-OFE, and Cu-HCP are the types of copper for which minimum values for the electrical conductivity are guaranteed. Cu-ETP is less suitable for welding or for brazing in reducing atmospherebecause of the oxygen content (danger of hydrogen embrittlement). Cu-HCP, Cu-DLP, and Cu-DHP are oxygen free copper types de-oxidized withdifferent phosphorus contents. With increasing phosphorus content theelectrical conductivity decreases. Cu-OFE, also called OFHC copper, is free ofoxygen and also free of de-oxidizing compounds.