Richard Clark wrote:

Hi Roy,

If I recall history and physics correctly (and simultaneously), house
wiring failed through cold flow, a property of aluminum to relax under
a one-time application of pressure (impulse rather than sustained
pressure) and thus the joint failed. The failure raised resistance,
resistance raised temperature, temperature raised flames.... no more
common use of aluminum in house wiring.

When I put in a new service entrance in 1979, it was after the problems
with ordinary aluminum house wiring were discovered and it was no longer
being used. But the service entrance cable I got was aluminum. The
service box connectors are marked as approved for both aluminum and
copper wiring, and have a compression fitting which doesn't give the
aluminum anywhere to flow. Generous application of NoAlOx or a similar
grease was also required for proper installation, so that's what I did.
It's been completely trouble-free for nearly 30 years now. So it was,
and is, possible to use aluminum wire. But it has to be done correctly,
with due regard to its vagaries.

Roy Lewallen, W7EL