Roy Lewallen wrote:
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


Roy;

The problem with AL house wire is that the pure Al that the wire is made
of will flow under pressure. When it was used with Cu wire switches and
outlets the attachment points could not maintain the pressure to insure
adequate contact.
At work one day the personnel department secretary requested one of the
company two way radios for her desk. I installed a Motorola HT220 in a
desk charger and plugged it into the outlet next to her desk. That night
the mobile home trailer that we used for personnel burnt to the ground.
To this day I don't know if there was a connection. ;^)... However, the
radio was a mess. The trailer was manufactured during the copper
shortage that necessitated the use of Al wire.

Dave Nagel WD9BDZ