Re: Aluminum Wiring Re: Electrical Properties of Brass

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Mark Broker by way of Terry Fritz <teslalist-at-qwest-dot-net>" <mbroker-at-thegeekgroup-dot-org>

Dan,

You are correct about making connections using aluminum wire in a 
residential or industrial branch circuit (most mains cable I've seen is 
aluminum, FWIW).  However, wiring a home or business with it uses methods 
that cut through the oxide layer and prevent further oxidation at the 
connection.  I was specifically referring to aluminum strip or tube/round 
used as a primary conductor, where the connections are frequently far less 
rigorous.  Most tap mechanisms I've seen on web pages and whatnot appear to 
be something along the lines of a fuse holder, which I would think is 
unable to cut through the aluminum oxide layer and make an air-tight seal.
YMMV, though, I guess.

Regards,

Mark Broker
Chief Engineer, The Geek Group

On Sat, 19 Apr 2003 22:52:39 -0600, Tesla list <tesla-at-pupman-dot-com> wrote:

>Original poster: "by way of Terry Fritz <teslalist-at-qwest-dot-net>" 
><dhmccauley-at-spacecatlighting-dot-com>
>
> > However, it is still difficult to make a good electrical connection with
> > the aluminum, since oxidation occurs in minutes.  Connections have to be
> > made air tight to prevent the oxidation process, which probably already
> > started before the connection was made air tight (work in an argon-rich
> > atmosphere, perhaps?).
> >
> > So I, too, would agree with Terry's recomendation against using it.
> > Mark Broker
> > Chief Engineer, The Geek Group
>
>
>Mark, All,
>
>Actually, this isn't true.  Aluminum was widely installed in homes in the
>United States in 1960's to 1970's.  And yes, in some homes, fires occurred
>within a
>few years of construction which is the primary reason aluminum wires for
>branch circuits in homes were discontinued.  HOWEVER, the oxidation of the
>aluminum
>was NOT the cause of these fires.  The problem stemmed from the fact that
>aluminum connections had a much greater tendency to become loose (i.e.
>circuit breakers,
>switches, various fixtures, etc...) and this ultimately led to fires.
>Aluminum expands much faster and more than copper, so if aluminum wire is
>attached to a copper terminal
>screw or connector, it can loosen.  In time, the connection can badly
>overheat and fail, leading to arcing and fires.  Actually, one of the
>biggest problems today when people find
>out they have aluminum wiring in their homes is that they get conned by
>electricians stating they need the entire house rewired with copper wire
>when instead, a qualified
>electrician can simply retrofit the aluminum wiring with safer-type
>connections which basically renders the entire home safe.
>
>Aluminum wiring can be very safe and effective.  And almost all the problems
>resulting from aluminum wiring were the result of unqualified homeowners
>modifying their aluminum-wired
>branch circuits such as adding outlets, other circuits, etc...  If a
>qualified electrician performs the work, aluminum wiring is as safe as
>copper wiring.  The only bad point about it
>is that aluminum wiring doesn't perform as well as copper wiring.
>
>Aluminum wiring is still widely used today even in homes as new
>installations.  Code prohibits the use of aluminum wiring (new work) for
>low-current circuits (branch circuits) such
>as outlets, lights, etc..., but it is still used for high-current service
>connections such as dryers, air conditioners, stoves, etc...  And
>electricians certainly don't make the connections in
>an airtight environment as Mark has said above.
>
>
>The Captain
>