I wouldn't be concerned about induced voltage into the Romex. In the event
of a direct hit (unlikely) anything conductive is subject to arcing over to
the line carrying the lightning current and then continuing to distribute
that fault current. The Romex should have been an electrical conduit run
buried 24 inches minimum per NEC. There is no place that allows direct
burial of six inches! It is a shock hazard waiting for an accident to
happen (someone will be planting a bush and dig into it with a shovel!
Yes, tie the tower to the house ground ring with a single run of #4 (or
larger) wire. Do not rely on the coax shields.
The thing that never ceases to amaze me, though, is why do all of the
grounding for the tower and around the house and not put lightning points
(terminals) on the house that are properly tied to the ground ring and
grounding system?
Always keep in mind that the most damage during a storm is caused by
voltages induced into the phone line followed by voltages induced into the
electrical line.
Do everything you can to protect yourself and your station, then disconnect
all antennas and other lines from the shack at the approach of a storm.
-----Original Message-----
From: towertalk-admin@contesting.com
[mailto:towertalk-admin@contesting.com]On Behalf Of brewerj@squared.com
Sent: Monday, September 16, 2002 12:41 PM
To: towertalk@contesting.com
Subject: [Towertalk] creating ground "surround" of house: Obstacle
I'm working on the ground field of my new towerette (40' Rohn 25). The tower
is guyed
and is about 70 feet from my house, and the radio room (2nd floor shack).
Following some of the dialog here and that in the recent QST magazines, I'm
grounding
at the tower, with multiple runs of 8' ground rods every 16', connected by
bare, buried #4.
My service entrance is on the far opposite side of my house from the shack.
A single point
ground is not therefore easily accomplishable. In order to tie the shack
entrance (for coax
and rotor cable runs) to the service entrance, I'm going to work my way
around the back of the
house, with more 8'
ground rods every 16' connected with buried #4 until I can tie in the
service entrance.
I have several questions:
1) Should I tie the ground ring around the house to that at the tower base?
I understand that it will be (poorly!) via the coax shield, but I seem
to
remember reading that if the tower is a distance from the house,
that it was not always desirable to tie the tower ground field into
the ground ring around the house.
2) In accomplishing the ground ring around the house, to tie the
radio "service entrance" to the house service entrance,
I'm going to encounter a section of direct burial Romex that
is only about 6" under the surface. It's there to power the septic
sump
pump.
How should I cross that run? There's really no way to go "around"
it. Even though they'll cross at right angles, I'm concerned about
inducing voltage into that romex run, and therefore into the house.
Should I be concerned?
Thanks one and all....
/John (waiting for the rain to stop!) WB5OAU/4
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