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Re: [Phys-L] aluminum resistivity

In 1913, a standard for commercially pure annealed copper was established by International Electrotechinical Commission (IEC). This is 1.7241E-8 ohm-meter.
Since then, other commercial conductors are rated in terms of a percent conductivity of the IEC standard for annealed copper.

This ranges from as high as 103% IACS (for modern methods of purifying copper)
to 61% to 62.6% IACS for 1350 aluminum (Aluminum which contains less than 1% of impurities) and 18% IACS for iron.
Overhead aluminum cables carry support core wires of steel which are said to contribute little to heating effect at AC frequencies where the (60Hz) skin depth may be limited to 9 mm in a 25 mm cable.
I notice that the range 61% to 62.6% of IACS conductivity represents an aluminum resistivity of 28.26 nano ohm-meter to 27.54 nano ohm-meter.
The lower resistivity value (26.5 nanohm.m) that Anthony gives for aluminum is likely to have derived from high-purity annealed samples of aluminum, which are not used in high voltage overhead power lines.

Brian Whatcott Altus OK Indian Territory.

On 7/21/2014 10:05 AM, Anthony Lapinski wrote:
I was doing a quick calculation for the resistance of a high-voltage power
line. I looked online for the resistivity of aluminum, but was getting
conflicting results. In units of nanoohm-meters, some had 28.2 while
others had 26.5. I realize the effect is very small, but I was surprised
by these discrepancies. Does anyone know what the "actual" value should be?

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