I purchased 90 meters of 0.35mm2 stranded copper conductor wire. How can I test this wire for conductivity to ensure quality copper was used?


closed as too broad by Dmitry Grigoryev, Huisman, Dave Tweed Jul 9 at 12:18

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  • \$\begingroup\$ Is one length of 90m or 10m from each supplier? \$\endgroup\$ – Solar Mike Jul 9 at 8:10
  • \$\begingroup\$ I think you need to figure out what is important in your application. If it is just conductivity then a resistance measurement will give you what you need to know. If it's insulation then you need to do an insulation test. If it's flexibility then ... \$\endgroup\$ – Transistor Jul 9 at 8:24
  • \$\begingroup\$ What's "high quality" for you? \$\endgroup\$ – Dmitry Grigoryev Jul 9 at 8:36
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    \$\begingroup\$ If you're basing large purchases on small initial samples, you should beware the "golden sample" phenomenon as well as "quality fade". It's best to establish objective quantitative metrics and inspect at the factory to ensure they are maintained. \$\endgroup\$ – Spehro Pefhany Jul 9 at 8:59
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    \$\begingroup\$ Been there, done that, found we were being sold wire with resistivity of about 120% IACS. Since this size wire has only about 50milliohms per meter, you need to carefully set up a 4 point (Kelvin) measurement with the voltage probes a defined distance apart (we made up a jig for repeatability) with the current connections outside the length you measure voltage over. It may be that you get worse conductivity wire that still meets the per unit length resistance by dint of there being larger stranding, unless weight is an issue that will still meet your needs. \$\endgroup\$ – Phil G Jul 9 at 13:47

measure the resistance: connect a 2A (or whatever load) in series with the wire and measure the voltage drop across the wire.

compare that with the published resistance for pure copper wire of similar cross section.


simulate this circuit – Schematic created using CircuitLab


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