"Jimmie D" wrote in message
...



One way to determine the low frequency effectiveness of a ground is to
connect the hot side of the power mains to the ground through a fuse and
see
how big of a fuse you can blow. There are special devices built for doing
this but it can easily and safely be done with less than professional
equipment. Just get all the pets and kids out of the way first.

Well, yeah! :-)

But there is a standard test for ground conductivity. Some pros told me how
they do it.

Drive three ground rods, A, B and C along a line. Pass a known current
between A and C. Measure the voltage drop between A and B. Ohm's Law will
give you the resistance at that place. I don't personally know what a
"good" number is for that test -- however,
http://mrtmag.com/techspeak/radio_we...ed_principles/ suggests 10 ohms.
These guys http://www.rainmaster.com/pdf/TB025C.pdf say the NEC wants no
more than 25 ohms.

I suppose if the soil conductivity is poor, multiple interconnected rods are
advisable/required.