[TenTec] ufer ground?

[Robert Mcgraw]

JIm's response, specifically his last sentence, is absolutely correct and
one that many hams fail to accomplish.

73
Bob, K4TAX




> On 8/12/2013 7:03 AM, GARY HUBER wrote:
>> My previous work place used a Ufer ground mat (basement floor rebar of
>> all buildings of the complex) bonded to building steel (and pilings)
>> with copper grounding bars bonded to them. An external ground ring
>> with ground rods was bonded to each vertical building steel member,
>> with air terminals (on each building roof) bonded to building steel.
>> Copper grounding bars in 14th story equipment room were connected to
>> the ground mat with a 250 foot run of a pair of 400 MCM cables. The
>> electrical service neutral and mechanical ground were also referenced
>> to the ground mat.
>
> Everything sounds exactly right about that except the separate 250 ft
> run, which is certainly legal, but would just as well be done to
> building steel on the 14th floor. The virtue of going to building steel
> is that there are many paths in parallel, and they are all bonded
> together at multiple points, which does two very important things. The
> paths are in parallel, thus minimizing the inductance to earth (a much
> greater component of the impedance to earth than the resistance), and
> the bonds between them at adjacent points minimizes the potential
> difference between adjacent points.  Indeed, bonding all the grounds is
> REQUIRED, not optional.
>
> 73, Jim K9YC
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