[TowerTalk] Hazards of low soil conductivity

[Lux, Jim]

On 1/9/22 8:10 PM, Jim Brown wrote:
> On 1/9/2022 3:26 PM, Richard (Rick) Karlquist wrote:
>> The grounds for these independent systems are subject to considerable 
>> voltage differences and will draw considerable current if you try to 
>> connect them together.  Note that for this purpose, "ground" and 
>> "neutral" are the same circuit.
>
> Engineers from BBC and ABC-TV were active members of the AES Standards 
> Committee, on which I have served for nearly a quarter century. ABC-TV 
> has (or had at that time) major facilities on opposite sides of a 
> major street in Manhattan, and the shields of video tie lines between 
> them saw exactly this problem in a big way. With audio, it could be 
> solved with transformers, but the signal bandwidth was far to great 
> for video.


Manhattan is notorious for this kind of problem. Dogs (and people) 
getting shocked while peeing on the sidewalk, etc.   Lots of wiring 
through old lead gas pipes, and hey, lead isn't a great grounding conductor.

We had some folks from ConEd at JPL more than 10 years ago asking if 
there's some way you could "visualize" the fields and surface potentials 
(shortly after a notorious lawsuit, as I recall).