what percentage of copper in wire
Is copper wire 100 percent copper? Very few things are 100% You can find copper wire with 99.999% purity commercially. The purity of copper is expressed as 4N for 99.99% pure or 7N for 99.99999% pure. The nâ¦umeral gives the number of nines after the decimal point when expressed as a decimal (e.g. 4N means 0.9999, or 99.99%). Much electrical wiring is not more than 99,9% copper.