By below grade I mean under the soil. It is not a good idea to have any
metal exiting concrete under the soil for reasons mentioned.
The ground rod under the foundation will probably not have any useful effect
anyway as the length of the total ground gets too deep.
A 20 foot pipe will be a waste for a ground rod unless you have extremely
dry soil and there is no other way to get moist soil. Otherwise 20 feet deep
gets too deep to have any useful effect. You would be better off using half
that length and putting in 2 rods. Going to larger diameters also has little
effect.
73
Gary K4FMX
> -----Original Message-----
> From: towertalk-bounces@contesting.com [mailto:towertalk-
> bounces@contesting.com] On Behalf Of W7CE
> Sent: Thursday, September 13, 2007 11:02 PM
> To: towertalk@contesting.com
> Subject: Re: [TowerTalk] Ufer ground using copper wire
>
> Sinking the ground rod several inches below the bottom of the foundation
> hole and only running copper wire out the bottom of the concrete is no
> problem. If house foundations use copper wire for Ufer grounds, then it
> sounds safe to assume that copper embedded in concrete does not eventually
> corrode away.
>
> I figured that putting the copper rod below the foundation would increase
> the sphere of influence (I think that is the correct term) compared to
> putting a copper rod at the surface. A friend in the tower business
> suggested that I should consider 1" diameter copper pipe sunk 20' into the
> ground and I may consider doing that as well. I can pound in 8' ground
> rods
> with a regular hammer here, so I suspect that with a little thought, I can
> probably get 20' rods installed. I typically find water about 8-10 feet
> below the surface here since I live on a lake, although I don't know if
> that
> will improve the grounding at all. At the very least I'll also install
> several 8' ground rods away from the tower base. Here in Western
> Washington, we rarely get lightning and I've never heard of a local ham
> being struck by lightning, but I might as well be safe.
>
> 73,
> Clay W7CE
>
>
> ----- Original Message -----
> From: "David Gilbert" <xdavid@cis-broadband.com>
> To: <towertalk@contesting.com>
> Sent: Thursday, September 13, 2007 1:07 PM
> Subject: Re: [TowerTalk] Ufer ground using copper wire
>
>
> >
> > I assume you mean the top end of the copper clad steel ground rod
> > shouldn't be embedded in the concrete, and that is true. But if he
> > buries the Cadweld joint (wire to ground rod) in the dirt below the
> > bottom of the hole, with only the copper wire entering the concrete, I
> > can't see where there would be an issue (discounting the urban legends
> > about exploding concrete, of course). Ufer grounds for house
> > foundations have the copper wire exit the concrete below grade all of
> > the time without worry about corrosion.
> >
> > 73,
> > Dave AB7E
> >
> >
> >
> > Gary Schafer wrote:
> >> You don't want anything sticking out of the concrete below grade. It
> will
> >> corrode and work its way into the concrete.
> >>
> >> 73
> >> Gary K4FMX
> >>
> >>
> >>> -----Original Message-----
> >>> From: towertalk-bounces@contesting.com [mailto:towertalk-
> >>> bounces@contesting.com] On Behalf Of W7CE
> >>> Sent: Thursday, September 13, 2007 10:43 AM
> >>> To: towertalk@contesting.com
> >>> Subject: [TowerTalk] Ufer ground using copper wire
> >>>
> >>> I'm planning on an Ufer ground in my new tower base. I've seen
> several
> >>> sites recommending 20' or more of #2 or larger copper wire wrapped
> >>> around
> >>> the outside of the rebar cage. Are there any chemical reactions that
> >>> make
> >>> using copper a bad idea? I seem to recall reading something about
> that
> >>> a
> >>> while back, but now I can't find any mention of it.
> >>>
> >>> If copper is ok, I'm thinking about putting a pounding a copper ground
> >>> rod
> >>> into the bottom of the foundation hole. The copper wire will be
> >>> attached
> >>> to
> >>> it and then wrap around the rebar cage and come out the top of the
> pad.
> >>> Comments or suggestions anyone?
> >>>
> >>> 73,
> >>> Clay W7CE
> >>>
> >>>
> >>> _______________________________________________
> >>>
> >>>
> >>>
> >>> _______________________________________________
> >>> TowerTalk mailing list
> >>> TowerTalk@contesting.com
> >>> http://lists.contesting.com/mailman/listinfo/towertalk
> >>>
> >>
> >>
> >> _______________________________________________
> >>
> >>
> >>
> >> _______________________________________________
> >> TowerTalk mailing list
> >> TowerTalk@contesting.com
> >> http://lists.contesting.com/mailman/listinfo/towertalk
> >>
> >>
> > _______________________________________________
> >
> >
> >
> > _______________________________________________
> > TowerTalk mailing list
> > TowerTalk@contesting.com
> > http://lists.contesting.com/mailman/listinfo/towertalk
>
> _______________________________________________
>
>
>
> _______________________________________________
> TowerTalk mailing list
> TowerTalk@contesting.com
> http://lists.contesting.com/mailman/listinfo/towertalk
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|