Peter:
My comments embedded below.
73 de
Gene Smr AD3F
From: Peter Dougherty <w2irt@comcast.net>
Date: 2007/06/18 Mon AM 09:12:43 CDT
To: towertalk@contesting.com
Subject: Re: [TowerTalk] Cadwelding and grounding nightmare
> Jerry speaks the truth. A rented trencher, like a Ditchwitch,
> would make short work of your trenching project. I dug trenches
> for my grounding wires and for my conduit system in one day with a rental.
The problem with a ditchwitch is it seriously wrecks the lawn - a
real no-no here. With summer here, guests over, etc, that won't fly
with the war department, if you catch my meaning. covert "slits" in
the ground will pass muster. We're using AWG 4, not copper strap (too
expensive).
******** Seems like the decision to use something other than a ditchwitch has
already been made for you. The issue with a shallow slit for lightning/ground
wire is that the top layer of soil will dry out very quickly, leaving that
layer with little conductivity to aid in shunting any lightning energy to
earth. I buried my #2 conductors down about 18 inches in moist clay* - hence
the need for machine digging (the wire trenches were a total of 135 feet long
at this QTH.)
* I dug my trenches during July of 2001, during a record-setting heat wave
here in DC, both in terms of high temps and duration. The earth at a foot to a
foot and a half in the trenches was wet clay, even during those hot conditions.
And I lost about 15 pounds that summer. Don't worry - it's all back now.
> Jerry is also correct in suggesting that the molten shot is
> running out of the holes in the (I assume) One-shot Cadweld molds.
There was no evidence of this happening. I did 3 more shots later on
and I think they all held (I'm not about to wiggle anything to "test
that theory," thus tempting fate, if I don't have to. I went off
properly, nothing appeared to "leak out" and when I went to break off
the mold 20 minutes later I bumped the wire coming from the tower and
out she popped.
************ You SHOULD tempt fate with all those connections. If they are
poorly made and about to break, they WILL break eventually with any shifting of
earth over time. I agree with another earlier poster that, if there is no
evidence of leakage as you say, then you might have too large a shot for the #4
wire you're using. Make sure you have the correct part number for the shot to
use with #4 solid (?) wire.
> I had the same problem with the first one I tried. After I cut
> off the half-welded top of the ground rod and fixed a second
> ceramic mold on top of it, I sealed the holes for the side wires
> and around the rod itself, underneath the mold, with electrician's
> putty (available at Home Despot, Lowe's, etc.) I did twelve welds
> successfully thereafter.
I've never heard of electrician's putty. Is it something that the
brain-fried clerks in HD could point me to?
*********** It comes in a plastic-wrapped package and is made by GB among
others. You will probably find it near the electrical connectors at HD, etc.
This is the stuff that is used to plug up the hole on the side of your house
where the electrical service enters your basement after the meterhead. If your
HD clerk has gray hair and eyeglasses, he can probably help you find it.
Cheers,
Peter,
W2IRT
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