Re: Zapping Camera Problem

["ABLE1" <nospamhere@xxxxxxxxxxx>]

<westom1@xxxxxxxxx> wrote in message
news:fb0f4b5d-dc74-4daf-b9a5-30fd019ee2c4@xxxxxxxxxxxxxxxxxxx
On Thursday, May 23, 2013 6:36:32 AM UTC-4, ABLE1 wrote:

> Having a problem with continued Camera location being Zapped when a storm
> goes by.

  Robert Macy's reply was spot on.  Others misunderstood some of his points.
For example, conduit or other grounds that are that long are (essentially)
non-existent.  For surge protection, even length of a wire is critical.
Even a sharp wire bend compromises protection.

  To resummarize his points.  Your camera 200 feet away must be handled as
if two completely different structures.  Using the same protection method
implemented between your home and the telco's CO.  Each structure must have
its own single point earth ground. Camera will never be earthed by the
building's ground. Otherwise, a lightning strike to one building (ie the
house) is a direct lightning strike to electronics in the other structure
(video section of a camera).

  Do not earth the camera.  That makes a camera the better and destructive
connection to earth.  Earth every incoming conductor to that camera.  And
again, the earthing must be low impedance - as short as possible (ie 'less
than 10 feet').

  This professional's application note demonstrates the concept - The Need
for Coordinated Protection:
http://www.erico.com/public/library/fep/technotes/tncr002.pdf

  In your case, replace that antenna tower with a camera.  The tower and
building both have their own single point earth ground (all four words are
electrically significant).  Any wire that enter the building or camera must
first connect to earth ground.  Either directly (ie the shield of a coax) or
via a protector (ie 12 VDC).  If any one wire in any cable violates that
rule, then damage can result either to electronics inside the building or
camera.

  Also important.  Makes no difference if the wire is overhead or
underground.  Same rules apply as that application note says.

  Do not earth a camera.  Earth the surge.  A major difference.  Even joints
in conduit compromise protection.  If a ground wire is inside a metallic
conduit, then it also does not earth a surge.  It is not about wire
thickness.  Most critical is conductor 'length'. No splices.  No sharp wire
bends. Otherwise impedance is too high - the earth ground connection all but
does not exist.

  A surge is electrically different from electricity that powers appliances.
Even wires must be routed with greatest care.  Protectors are simple
science.  Most important is the art of protection - single point earth
ground.
=========================================================================

With this post it does clear up a few points.

Thanks, very helpful.

Les