[TowerTalk] Question About Safety Routing of Wires?

Eric Gustafson n7cl@mmsi.com
Sun, 3 Oct 1999 10:48:15 -0700



Hi David,

I had a bit of trouble deciphering the drawing after it had gone
through some email format mangling.  But I _think_ I understand
your situation now.


>From: "DavidC" <eDoc@netzero.net>
>Date: Sat, 2 Oct 1999 21:54:47 -0400
>

Snip...  (ASCII Drawing and symbol legend)


>QUESTIONS:
>
>1.  I intend to remove the shed because it is wood, the sills
>     are bad, and because it sits on blocks where beasties and
>     termites live and feed.
>     
>     Should I eliminate the phone line there as a possible
>     source of circulating currents from lightning?  I have no
>     need for a phone in the shed.  (This is the line labeled
>     "SP" in the diagram.)

I would.  Nowadays, 900 MHz spread spectrum wireless phones are
so good that it would be hard for me to contemplate using
anything else for outbuilding phone service.  Mine covers all of
8.5 acres with no bad spots.  So even if you changed your mind
later, there would really be no need to run wires for remote
phone service.



>2.  I am thinking of disconnecting the Well line and using the
>    PVC-protected line that runs to the shed instead.  Is the
>    path of the SE line preferable to that of the W line
>    (esp. the way they are routed differently inside of the
>    house)?
>
>3.  Should I eliminate the E2 line since it is no longer needed
>    for a SPA and looks like trouble?

I would eliminate all unused conductors from the system.



>4.  Should I do something about the CATV line?  We have no plans
>    to activate it and I have a thought of asking them to
>    terminate it back at Pole 2.  Otherwise I am thinking I
>    should relocate their box next to the Phone Co. box and
>    ground it to the same rod as the Phone Co.  and Electric Co.

I would do this.  And later if you decide to have them reinstall
service, make them use the service entry ground correctly (as you
already indicate) like the power and phone companies have.  You
could even have them come in through a PolyPhaser protector on
your single point ground panel.



>5.  The Phone & Electric ground rod runs straight down next to
>    the foundation.  Should I add several others at angles away
>    from the foundation?  Should I relocate the existing rod
>    also at an angle?

This rod is fine.  But, if you want to lower its impedance a bit,
you could bury a large conductor (#4 or larger up to #00) 18
inches or more deep running parallel to the foundation for an
equal distance in either direction from the rod.  If you do this,
make the length of the opposing runs at least 10 feet.  If your
soil is soft clay or loam, the dirt by itself is fine.  But if
you are in rocky or sandy soil, you may want to surround the
conductor in the trench with Ground Enhancement Material (GEM).
This makes sort of a poor man's afterthought UFER ground.  GEM
can be purchased premixed or you can make your own.  Of course
these buried ground conductors connect to the rod or to the
single point ground panel (which also connects to the rod).  If
you run them more than 10 feet (20 or so) and you feel the need,
you can drive ground rods at the ends of the runs and bond these
conductors to the additional rods.


>
>6.  My plan is to place a shared entry and grounding panel next
>    to the ground rod on the outside wall which is just below
>    the breaker panel.  This way I can route my antenna and
>    rotor lines through it using Polyphaser devices.  Do I need
>    to do something different with the Electric, CATV and Phone
>    Co. lines?  (Do they also need to pass through that
>    grounding panel?)

Once you have established a single point ground panel, it is a
good idea to locate the surge suppression for all conductive
entry to the house on it.  And to use it for the ground reference
point for the shields of all shielded wiring entering the house.
If you bond the current Electric Power service entry box to the
single point panel (made easier by locating the panel directly
adjacent to the electric entry box), then you won't have to cange
anything about the way the electric service is already handled
beyond possibly having an electrician install a main panel MOV
surge suppressor on the box.

73, Eric  N7CL

--
FAQ on WWW:               http://www.contesting.com/towertalkfaq.html
Submissions:              towertalk@contesting.com
Administrative requests:  towertalk-REQUEST@contesting.com
Problems:                 owner-towertalk@contesting.com
Search:                   http://www.contesting.com/km9p/search.htm