A while back there was a discusion about grounding a system and I found this and thought that I would share it with the rest of you. The following is a cut-n-paste from homepower magazine, issue #103
Grounding Electrode
The "grounding electrode" can be a number of different
devices. In many places, the commonly used electrode is an
8-foot (2.4 m) long, 5/8-inch (16 mm) diameter copper-coated
steel rod driven into the earth. The entire length of the rod
must be in contact with the earth, so the top is usually flush
with, or buried slightly below the surface. Clamps rated for
direct burial are used to connect the grounding-electrode
conductor to the grounding electrode.
The code requires that the resistance from the rod to
the earth be 25 ohms or less. This measurement is difficult
without specialized equipment. To do it accurately, you
have to use instruments that cost hundreds of dollars.
If the measurement is greater than 25 ohms, a second rod
must be driven at least 6 feet (1.8 m) away and bonded to
the first rod. The bonding conductor must be the size of the
grounding-electrode conductor. The rods may be driven up
to 45 degrees from the vertical in rocky soils or buried in a
trench horizontally at least 30 inches (76 cm) deep.
Sometimes, a 20-foot (6 m) length of #4 (21 mm2) bare
copper conductor is buried in the concrete footer or slab
for the house, and serves as the grounding electrode.
Connecting the grounding-electrode conductor to grounded
water pipes, well casings, or grounded building steel is
also allowed in some cases. These requirements are code
minimums. If the installation is in a high lightning area,
much more extensive grounding systems will be beneficial.
Equipment-Grounding
Conductor Size
Overcurrent Device
Rating (A)
Minimum Equipment-Grounding
Conductor Size (AWG)
(A)15 (AWG)14
20 12
30 10
40 10
60 10
100 8
200 6
300 4
I hope that this might help clear any questions about grounding, I know it made me decide to up the size of the wire I was going to use to ground my genny (if I ever get enuff time and parts to finish it)
Wired_Wrong, OKC,OK
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