In a message dated 98-06-04 20:26:16 EDT, email@example.com writes:
<< First, the manual doesn't say how long the test electrodes should be (i.e.,
how far into the ground they should be pounded.) Does anyone know? Can I use
a couple of those short TV-type rods from Rad Shack for the electrodes, or
do I need to use some 8' rods? Second, since all my ground wires are
Cadwelded to the existing rods, I can't disconnect them. There's one rod
attached to the tower where I could disconnect the lead at the tower base to
isolate the rod, but that would be rather a chore.
I'm sure that it depends on what the system is design around. Several of
the Megger ground resistance instruments use 20 inch probes.
The ground resistance devices I've seen all use flexible copper wire for
their probes with some compression attachment method. That makes them easy to
Here's an interesting site that has the Megger devices and also a
library that has several interesting books on grounding as well as a pamphlet
on measuring ground resistances. http://www.avointl.com/home.html - check it
If you look at the Megger specs, you'll see some interesting information
>> I'm wondering if any meaningful measurements can be obtained by taking
readings on a ground rod that is connected to the rest of my grounding
system. Anybody know? I'm guessing that the readings would be lower than for
a single rod because the rods and radials would provide additional paths
from the test electrodes to the rod under measurement. True? Would that
number still be meaningful?
Probably. I'd search the web for the manufacturer and then contact them
to get a manual. That'll probably answer all your questions.
Cheers, Steve K7LXC
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