[TowerTalk] UFER Towerbase for 220ft "wifi" tower

Jim Lux jimlux at earthlink.net
Wed Jun 21 17:24:30 EDT 2006

At 11:53 AM 6/21/2006, Beat Meier wrote:
>I'm looking for an "easy" method  to calculate more or less a tower base 
>for my tower.
>The tower is NOT self supporting.
>Height: 66m (220ft)
>Shape: triangle
>Material: Painted steel, not galvanized.
>What is mounted are only "small" parabolid grids (1mx0.7m) and omni antennas.
>Every 6m there are the cables. From the base to half of the tower the 
>cables go to 25m point
>from the half to top to a 50m point
>         50m
>         |
>         |
>         |
>         .
>     /      \
>    /____\
>I want to use UFER ground. If read a lot of articles found in the forum 
>and the internet
>but no one tells about how many metall grid you should put in a tower base.

The 'electrical code' name for a UFER ground is "concrete encased grounding 
electrode" or words to that effect.

Usually, they require some length of conductor that is encased.  For 
instance, when my house was built (1998), the local code required no less 
than 20 ft of AWG 4 copper wire, as one alternative.

As far as the electrical code goes it's in section 250.52(A)(3) 
Concrete-Encased Electrode.

There's a discussion of just what you're wondering about at:

This article seems to imply that the Code requires 20 ft of conductor 
(without saying what the conductor has to be).  Amazingly, it would appear 
that the requirement is just that there's 20 ft of metal in the concrete, 
and it doesn't have to be contiguous, or even connected.  I suppose that 
the real issue is that there is enough conductor length to make the overall 
conductivity of the whole assembly low enough, and small gaps in the metal 
might not make any difference.  (Concrete in contact with soil is a fairly 
good conductor)

>Does for example a hole 1m (3ft) diameter, 2m deep (7ft) filled with 
>concred and steel meshes to the job?
>Are there any good sites with calculations? I have nothing found.
>Thanks a lot for any info
>Echte DSL-Flatrate dauerhaft für 0,- Euro*!
>"Feel free" mit GMX DSL! http://www.gmx.net/de/go/dsl
>TowerTalk mailing list
>TowerTalk at contesting.com

More information about the TowerTalk mailing list