I'm well aware of the problem, but I've been trying to figure out how I
can safely separate them. Almost everything ties to a grounding plate
where it enters the house and where it enters the shop. I think I
mentioned almost getting electrocuted when I lived in Breckenridge MI. I
was holding a bare # 10 wire about 36' long that hooked to an 8' ground
rod. When my knees touched the wet ground, it had me. That ground rod
was about 75' W of the service ground. The station ground was about 75'
E of the service ground, yet the resistance in "WET" ground was high
enough not to trip the breaker.
73
Roger (K8RI)
On 10/25/2014 7:35 PM, Bill Turner wrote:
------------ ORIGINAL MESSAGE ------------(may be snipped)
On Sat, 25 Oct 2014 17:55:18 -0400, you wrote:
The antenna ground system ties
to both buildings, essentially tying their service grounds together
through a network of over 600 feet of bare #2 cad welded to 32 or 33 8'
ground rods.
REPLY:
And therein lies the problem. Multiple grounds which are physically
separate but which are wired together. That is asking for trouble and
that is why the NEC requires a single point ground. Having separate
SPG's that are wired together is NOT a true SPG.
The ground itself is not a perfect conductor, far from it. When
lightning hits one of the grounds, it elevates that individual ground
potential well above the other grounds in the area, and if they are
wired together, guess what happens? Current flows between them and
that is BAD NEWS.
At my QTH, the tower and antennas have their own ground and the house
has its own ground, and when lightning is present they are totally
disconnected from each other. I believe that is the only safe way to
go.
73, Bill W6WRT
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73
Roger (K8RI)
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