[R-390] Some progress

Mon, 6 Jan 2003 13:05:23 -0600

Greetings group,

I work for Southern Company...the largest Public Electric Utility in the US
and to my knowledge all of our service entrance cables are Aluminum
"Tri-Plex" which consists of two insulated conductors and one bare...all
twisted together.  I can't speak for what is installed in higher current 3
phase installations.  Can't say I have seen any copper cables at all in our
warehouses besides direct burial control cables used in substations and
generating plants.

Most folks don't know it but all of the lines you see overhead including the
large 100KV and 500KV transmission lines are built with Aluminum (bare)
conductors.  Copper is no doubt better from a conductivity standpoint but
it's way too expensive to use for transmitting and distributing electricity.
I will tell you that the Aluminum that is used is not the soft, flexible
aluminum you might think of...it's some alloy that is like Hard Drawn copper
is to standard copper.  You can't hardly bend the stuff.  Must have better
corrosion properties as well...I have looked at conductors that have been in
the air for years and show little corrosion or pitting,  a good report for
the area I live in....Gulf Coast.  (read salt air)

Cecil Acuff

----- Original Message -----
From: Bob Tetrault <[email protected]>
To: Joe Foley <[email protected]>; <[email protected]>
Sent: Monday, January 06, 2003 12:25 PM
Subject: RE: [R-390] Some progress

> I think there must be some regional error here Joe, as all of my service
> entrances from the pole have been copper, even as late as 96.
>
> California and Oregon
>
> Bob
>
> -----Original Message-----
> From: [email protected] [mailto:[email protected]]On
> Behalf Of Joe Foley
> Sent: Sunday, January 05, 2003 10:38 AM
> To: [email protected]
> Subject: Re: [R-390] Some progress
>
>
>
> --- polaraligned <[email protected]> wrote:
> > Well, maybe Joe can expand on this, but I believe
> > aluminum wiring
> > is OK if done right.  That means using devices
> > designed for aluminum wiring
> > and
> > using the right compound on the connections.  I
> > think most electrical
> > services use
> > an aluminum feed from the pole to the panel.  The
> > busses in the panels on
> > many
> > services are aluminum.  And the electrical inspector
> > will want to see a
> > proper
> > compound on the service connections.
> ++++++++
> Yes, all the way through.
>
> Still aluminum isn't as good as copper, mostly because
> of the connections.  Aluminum is softer than copper
> and the connections should be tightened regularly as
> they come loose due to vibration, even in a house,
> also from heat cycling, whether from using the circuit
> or just winter/summer variations.  The outlet nearest
> the main entrance is the one most prone to having the
> screws come loose because of the wall being vibrated
> by slamming the door!  The kitchen counter will be the
> next worst, repeated plugging and un-plugging and high
> current draws from the appliances.
>
> Then this for owners of BIG radios, or lots of radio
> equipment:
>
> I posted this to the T-368/BC-610 list:
>
> House service neutral?
>
>
> Happy New Year everyone!
>
> During the discussions of the size circuit needed to
> run a
> transmitter such as a T-368/BC-610 one important item
> was
> overlooked. That is the condition of the neutral wire
> going from the
> panel out to the pole. Many times this is allowed to
> deteriorate to
> the point where it is no longer safe to carry such a
> large 120 volt
> load. In an overhead service the neutral is the group
> of wires
> wrapped around the two hot wires inside the service
> entrance cable.
> If the covering of this cable has disappeared, for
> whatever reason,
> those wires are open to corrosion damage which may not
> take long to
> cause them to disappear altogether! This is often not
> considered by
> the average homeowner.
>
> What will happen if this fails is that 240 volts will
> be acrossed all
> of the 120 volt circuits with the appliances making a
> voltage
> divider. What voltage each appliance sees will be
> determined by its
> impedance. Some will go POOF, some will just get hot
> enough to burn
> the house down.
>
> A 21 amp load being cycled on and off repeatedly will
> certainly
> stress an already weak neutral.
>
> ALL newer houses, I mean 30 years old, have aluminum
> service entrance
> cables! They haven't made copper service entrance
> cable in 40
> years! How long has it been since the bolts in your
> panel and meter
> socket were tightened? Are they tight enough to pass
> enough current
> to trip the breaker? Got any "blue" terminals? Melted
> plastic?
> Smoke trails up the siding?
>
> If its not moving, GROUND IT!!,.......... does your
> service actually
> HAVE a ground?
>
> Joe
>
>
>
>
>
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