To: atm{at}shore.net
From: mdholm{at}telerama.com
Reply-To: mdholm{at}telerama.com


Goraqn Hosinsky wrote:

>Even if both ends of the conduit are turned down to avoid water coming
>in I think there might be danger of condense when the temperature drops.
>Goran
>La  Palma

Good point.

That is only one of the reasons UL and CSA require wet immersion testing on
all wire and cable insulation and jackets.  I used to do some of that
testing.

It's also a good reason to keep the run as much under the frost line as
possible, less possibility of ice damage.

I think the first post in this thread mentioned possible insect damage.  As
I recall from my years in the wire and cable business, insect damage was
quite rare.  Rodents are a different story!  Mice, moles, gophers, rats,
etc. will chew through almost anything in their path.  I remember seeing
cables built with braided stainless steel ribbon as a rodent barrier that
were partially chewed through!  If you have the killer gophers in your
neighborhood, the only way to stop them may be metal conduit.  Fortunately,
the really determined ones seem to be a little uncommon.

As for Bob May's suggestion of using AC power plugs for DC, I wouldn't do
it myself.  1. Too easy to screw up and fry something or someone.  2. With
DC, you need to keep polarity correct.  Of course with polarized AC plugs,
that will work.  The biggest advantage to the AC connectors is easy
availability, and especially easy availability of mounting plates with the
correct size holes already punched.  Punches for odd sized connector holes
cost way more than the connectors.

Mark Holm
mdholm{at}telerama.com

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