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isw

In article ,
Jon Elson wrote:

wrote:

On Friday, January 6, 2017 at 9:52:54 AM UTC-5, wrote:

SNIPPAGE

a) Wire conductivity, irrespective of material, is a function of surface
area
Shouldn't that be CROSS-SECTIONAL area?
and gauge amongst other factors. So, if 14-gauge wire is then divided
into strands, the final product with the most strands will have the most
surface area, and so by some factor greater conductivity.
Yes, but actually, I think the conductivity is better with FEWER strands of
thicker wire. Many strands of tiny wire ends up being a lot of air and not
so much copper.

As for the original poster, that silvery coating on typical stranded wire is
tin or solder, NOT aluminum. It is there mostly to make the wire
solderable, but also acts as a corrosion inhibitor.

The only aluminum wire is used as power lead-ins to houses, as it is much
cheaper than copper. They did use aluminum wire INSIDE houses in the US
around 1966-1968, and it burned a lot of houses down, due to the cold flow
of aluminum weakening the contact force.

ISTR that the problem was mostly that electricians couldn't be bothered
to learn the new techniques and so on that were mandatory to install the
stuff safely. It was only when it was installed just like Cu that it was
prone to overheating.

Isaac