Wow. You can buy 100' of solid #6 copper wire almost anywhere in the US for
$100. Why spend thousands? For lightning protection? Not for me, and I'm a
survivor of a severe lightning injury.
K7DD is right. Bond to your SPG with as big a wire as you feel you can
afford. Longer path = bigger wire. Here's the NEC reference:
>From mikeholt.com:
"Any grounding electrode added for communications systems is required to be
bonded with a 6 AWG or larger conductor to the building or structure
grounding electrode system in accordance with 800.40(D), 810.21(J),
820.40(D), and 830.40(D)."
If you're in the US, this would apply as a minimum "best practice."
The real issue is the possibility of providing a path from your station
ground to your AC service ground through your equipment and house wiring -
you don't need to redirect a bolt of lightning. Bond directly from ground
point to ground point and the divided current would be proportionally very
low, so that your house won't catch fire, even if your electronics are
zapped. Use the money you save to pay insurance premiums if you wish.
The one thing I have found troubling in this thread is N4ZR's measurement of
100 Ohms to ground on one of his outlets. Pete, something is wrong. That is
WAY too high. AWG #14 should have a resistance of about 0.003 Ohms per foot,
so you have an open ground unless the outlet is miles from your service
entrance.
73 and be safe,
Mickey, N4MB
(90 or so feet of solid #6 between ground rods on opposite ends of the
house.)
To the fellow who measures 100 Ohms to ground
On Wed, Jun 16, 2010 at 8:13 PM, Roger (K8RI) <K8RI-on-TowerTalk@tm.net>wrote:
>
>
> On 6/16/2010 7:41 PM, Michael Baker wrote:
> > Relocation is also not always practical nor is it inexpensive.
> Professional
> > Electricians don't come cheap and moving an underground service entrance
> is
> > very involved and sometimes simply can't be done due to local codes and
> the
> > location of the service main.
> >
> Here the service comes in underground to the meter, then enters the
> house in the conventional way. That is on the front of the house.
> The ham shack is centrally located on the back side of the house. The
> only two rooms on the front are the kitchen and living room with an
> entryway between them.
> So relocating either is not an option. Even if we could run the service
> around to the back it would involve digging up a major portion of the
> ground system and part of the drain field. I doubt we could do it for
> under $20,000.
>
> 73
>
> Roger (K8RI)
>
> > My house is at the end of a street and the service entrance is opposite
> my
> > shack just outside my attached garage opposite the end of the street. I
> > would hazard a guess and say that maybe $4000 might cover it due to
> > trenching, new copper entry wire, a new entry panel and all the hardware,
> > local build fees and inspections, new concrete and landscaping as well as
> a
> > new sidewalk and driveway.
> > A single piece of 4/0 cable run from one end to the other would be
> cheaper
> > even with several ground rods and eutectic bonding. Even if you include
> the
> > trencher, having the driveway concrete sawed and filled afterwards, new
> bit
> > of concrete work to fix the cuts, etc is couldn't cost even half of that.
> >
> > Speaking of low impedance grounds, a flat sheet of copper with the
> > equivalent mil volume as a wire will have a much lower impedance. 4"
> copper
> > sheet that is .01" thick works wonderful even on mountain top sites. It
> just
> > makes attaching it to the ground rods a bit trickier to deal with. ;>)
> >
> > Michael Baker K7DD
> > k7dd@cox.net
> >
> > -----Original Message-----
> > From: towertalk-bounces@contesting.com
> > [mailto:towertalk-bounces@contesting.com] On Behalf Of W2RU - Bud
> Hippisley
> > Sent: Wednesday, June 16, 2010 3:15 PM
> > To: Tom Anderson
> > Cc: w4lde@numail.org; TowerTalk
> > Subject: Re: [TowerTalk] Shack ground
> >
> >
> > On Jun 16, 2010, at 5:27 PM, Tom Anderson wrote:
> >
> >
> >> Most grounding books and articles suggest tying the station ground to
> the
> >>
> > power company ground, but what do you do if the power company ground is
> on
> > the opposite side of the house from the shack?
> >
> > Relocate the shack, or relocate the service entrance. In my case, we did
> > the latter....
> >
> > I also had the telephone entrance relocated so that it came into the
> house
> > within a few feet of the power line. All grounds (power, telco, and ham
> > shack cables) are tied together just outside the shack.
> >
> > Bud, W2RU
> > _______________________________________________
> >
> >
> >
> > _______________________________________________
> > 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
>
--
Mickey Baker
Fort Lauderdale, FL
“Tell me, and I will listen. Show me, and I will understand. Involve me, and
I will learn.” Teton Lakota, American Indian Saying.
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|