AVR-Chat

Like Jim pointed out, on outdoor runs lighting is a problem, especially when
it comes to devices that can only withstand very small voltages.

About 20 years ago where I worked we had two buildings located about 3000
feet apart on our facility. The Northern Telcom phone system, cameras,
Honeywell building environmental, security and fire alarm system and
intercom communications ran in conduits between the two building complexes.
This equipment had lighting protection, especially the Northern Telcom
telephone system. We had a great lighting storm one afternoon and just about
everything on copper went out. None of the fiber equipment was hurt. It is
my belief that when the lightning hit a tree, the current ran down the tree
into the ground and through the roots, the roots were wrapped around the
conduits and the heavy rapid current spike in the roots wrapped around the
metallic conductor induced a huge electrical surge in the metallic
conductors, the surge had no were to go but into the equipment on both ends.

One sure fire way we over come this is the use of fiber optic cables.

I forgot the name of the company we did use for protection on those lines
that could not be converted to fiber but there products worked very good.
This is a link to Black Box the picture you will see is a protection device
that is made by that company and marketed by Black Box as there own. Contact
them and see if they have anything the will protect 5VDC lines. Or will
provide you with their supplier.
http://www.blackbox.com/Store/Detail.aspx/RS-232-Surge-Protector-DB9/SP361A%C4%82R2

Another method you could use is a optical coupled IC. You need to protect
both ends.

Mike


On Thu, Jun 17, 2010 at 9:41 AM, Zack Widup <w9sz.zack@gmail.com> wrote:

> Electronics engineers who are also geophysicists know about it!
> :-)
>
> Zack
>
> On Thu, Jun 17, 2010 at 2:20 AM, anickol <anickol@yahoo.com> wrote:
>
> >
> >
> >
> >
> > > Depending on where, in the world, this is being installed, it could
> > > last a long time as you propose, or it could be toast by this time
> > > next year.
> >
> > This is the true statement, precisely describing the situation.
> >
> >
> > > It took
> > > several years of sleuthing to figure out that near-by lightning strikes
> > > resulted in a current sheet through the top several feet of the earth.
> >
> > In fact, large voltage difference could appear even when there are no
> > lightnings at all. Geophysists know about this, electronics engineers
> does
> > not - this is a problem.
> >
> >
> >
>
>
> [Non-text portions of this message have been removed]
>
>
>
> ------------------------------------
>
> Yahoo! Groups Links
>
>
>
>


-- 
Linux since March 2004
www.counter.li.org
Registered Linux User: #482134
Taking up Linux Ubuntu and give-up the Windos habit.
Hasta la Vista, Baby. I won't be back!
Mike Bronosky
Mike@Bronosky.com


[Non-text portions of this message have been removed]