[RE-wrenches] Aluminum wire failure

[wlbryce at pineridgeproducts.com]

All,

In reality is is easy to find faults in underground feeder wire.
A tone trace device is installed on the feeder and a triangulation "A
Frame" is then used to find the fault. It is accurate within inches.

Have photos of device (3M Dynatel 2250) and failed aluminum wire if
interested. Extreamly common  in Montana soil.

Cheers

Logan



> Bob,
>
> I assume you are talking about feeders.
> Although most people are against aluminum
> wire it is really quite safe for feeders if installed properly.
> To do this the lugs should all be retorqued after one year.
> Aluminum "flows" under pressure, that is the steady pressure
> at the lug slowly squeezes the soft metal into the corners of the lug
> over time.  This leaves the lug not quite snug enough and a candidate for
> heat build up and eventually arcing.  When the lug is torqued after a year
> the flow to corners is done and it's good.  Disney was originally wired
> this way and the contact stipulated every feeder lug in the place was to
> be retorqued after 1yr under supervision of Disney engineers.
> I guess these days nobody wants to go back in a year so we pay for
> copper,certainly the best conductor of the two.
>
> Steve Johnson
> LightWave Solar
>
> On Aug 21, 2010, at 11:23 PM,
> "re-wrenches-request at lists.re-wrenches.org<mailto:re-wrenches-request at lists.re-wrenches.org>"<re-wrenches-request at lists.re-wrenches.org<mailto:re-wrenches-request at lists.re-wrenches.org>>
> wrote:
>
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> <Digest Header>
> <Today's Topics (5 messages)>
> We don't often get to take picture, as the point of failure is hard to
> find, and the entire underground line is just abandoned and a new cable is
> installed.
> Most failures I've seen (not actually seen) were on improperly installed
> runs, done by DIYers.
> On the other hand, the majority of underground service in New Mexico is
> done with direct burial Aluminum, and if done correctly (buried deep
> enough, bedded in sand, no rocks), it's not so bad.
> My regular suppliers don't even carry big copper, as the Al is so much
> cheaper, and comes in triplex, and 4 plex cables, but it's dry there.
> In Hawaii, you see much more copper, so I think it all depends on the
> conditions, both above and below the ground.
>
> R. Walters
> <mailto:ray at solarray.com>ray at solarray.com<mailto:ray at solarray.com>
> Solar Engineer
>
>
>
>
> On Aug 21, 2010, at 2:48 AM, bob wrote:
>
> Does anyone have any photos of aluminum wire that has failed? Failures
> from nicked insulation and such would help.
> I have a debate going with a customer who does not believe that it could
> cause a failure.
>
> If you have any digital pics please send them to my address,
> <mailto:reellison at gmail.com>
> reellison at gmail.com<mailto:reellison at gmail.com> instead of to the list.
> I know there are some out there somewhere?.
>
> Thanks,
> Bob Ellison
>
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