On Thu, 16 Aug 2007 20:38:51 -0500, Gary Schafer wrote:
>A great deal of lightning energy is
>connected to earth by capacitance in any ground system. Yes a DC (bare wire)
>connection would be better and help more with the low frequency energy
>coupling.
You might want to do some calcs (on the capacitive reactance of a big radial
system) before you say that a DC ground is BETTER. Having a DC connection in
addition to the capacitive coupling IS better, and is, in fact, required by
most building codes and common sense. But it is in parallel with the
capacitance, and most electrode grounds have a lot more resistance to "earth"
that you might think. Indeed, the inductance of the earth connection dominates
the impedance at a surprisingly low frequency.
73,
Jim Brown K9YC
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