[TowerTalk] Unique RFI/Grounding system

[Jim Lux]

Good point... for an older house, you would have the usual rod type ground.
A house I lived in in the 70's was built in 1970 and had a rod.
The house I live in now was built in 1998 and has a ufer ground.  In my 
case, since there's no rebar in the slab (it's a post tension slab, very 
common these days, because it's thinner and cheaper to make), they used the 
20 feet of #4 wire approach (at least I saw it there before they did the 
pour.. who knows if it's still there. Stranger things have happened before..)

The cables for the post tension are "jacketed" in some sort of plastic 
sleeve, so they don't have much electrical contribution.

All of the utilities come in as plastic pipe of one sort or another, so the 
"water pipe" ground would be useless.



At 04:44 PM 6/2/2003 -0700, Steven Gehring wrote:
>Hi Jim,
>
>I wasn't aware that my home's building ground was a specially designed,
>rebar welded ground spread throughout a building foundation.  I thought it
>was a just a ground rod here in WA (my house is 25 years old).  Check out
>these links:
>
>http://www.psihq.com/iread/ufergrnd.htm
>
>http://lists.contesting.com/_towertalk/1997-September/009267.html
>
>http://www.spgs-ground.com/typesA.html#anchor1772206
>
>Maybe in California the UFER ground is more standard. Reference:
>
>Ufer Ground
>
>
>TECHNICAL DETAILS
>
>When available the building reinforcing steel (rebar) is the preferred
>method for providing an electrode. Concrete Encased Electrodes (UFER) can
>consist of either a minimum of 20' of No. 4 copper wire or two or more No. 4
>or larger rebar installed in the foundation with a minimum of 2" of concrete
>cover. When using rebar, it must be spliced a minimum of 40 bar diameters,
>ex. 40bd x 1/2"=20" min splice length.




>-----Original Message-----
>From: Jim Lux [mailto:jimlux at earthlink.net]
>Sent: Monday, June 02, 2003 4:17 PM
>To: Steven Gehring; 'Mark Pride'; towertalk at contesting.com
>Subject: RE: [TowerTalk] Unique RFI/Grounding system
>
>
>At 03:44 PM 6/2/2003 -0700, Steven Gehring wrote:
> >Hi Mark,
> >
> >Do a search on the internet (Google) for what is called a UFER Ground.
> >There are many hits on this type of cement foundation grounding method.
> >I hope this helps...
> >
> >Besides following the NEC, I'd like to employ this method the next time
> >I build a new house.  I suppose this UFER ground could be bonded to the
> >building ground and a single point ground panel.
>
>
>The UFER ground IS the building ground. You wouldn't generally see a
>conventional ground stake tied to a UFER ground (if only because the UFER
>is a better ground.. lots of contact area, low impedance, etc.)
>
>One could use a UFER ground at the tower and at the shack, and tie them
>together per the NEC...
>
>Jim, W6RMK