PS Magazine - TB 43-PS-582
PS, The Preventative Maintenance Monthly
ISSUE 582
MAY 2001
PS 582
53
Grounding Mistakes?
PS 582
MAY 01
52
Mobile Subscriber Equipment.
..
Are You Making These
1. Not wearing safety goggles
when driving ground rods.
Safety goggles protect your
eyes from flying metal chips.
Don't think for a minute that a
piece of metal won't chip and
fly off while you're doing the
hammering. Lucky Larson
thought that and now he's
called One-Eyed Willie.
2. Not driving the 8-ft ground rod, NSN
5975-00-296-5324, beneath the soil surface.
Before you drive the rod into the ground,
dig a hole about 18 inches square and 8
inches deep. Then drive the top of the rod to
about 3 inches above the bottom of the hole.
Keeping the top of the rod below the surface
of the ground reduces dangerous voltages
near the rod during a storm. And that also
keeps you from tripping over it.
After you attach the ground strap to the rod, fill the hole with water and let it soak
in. Then fill the hole with dirt. Add water as often as needed to keep the soil moist
around the rod. A good constant source of water is your air-conditioning unit. Run
a tube from the air-conditioner drain to the rod area to keep the soil wet.
Just because the connection between the
strap and the rod is out of sight doesn't mean
it should be out of mind. Check it every day
to make sure it stays connected and tight.
People walking around the ground can unin-
tentionally pull the strap loose. Unless you
check it regularly, you won't know if you're
still grounded.
If rocky or frozen ground stops you from
driving a ground rod deep enough, consider
other forms of grounding or multiple ground
rods. See TC 11-6 or FM 5-424 to learn how.
3. Not using the right type of grounding strap.
The ground strap must be as large as pos-
sible—at least 6 AWG. A flat-surface strap
is much better than a round one since there
is more surface area and current passes over
the surface and not through the strap. The
strap should be copper or copper-clad alu-
minum. The best strap is made of braided
copper. If steel or stainless steel must be
used, it should be only temporary and
inspected often for corrosion.
Drive rod
below soil
surface
Fill with
dirt and
water
Air
conditioner
Use a flat-
surface strap
Wear
goggles
when
driving
rods
A
recent tour of some
MSE shelter sites
turned up a nasty handful
of earth-grounding
mistakes. Check 'em out
and make sure you're
not making them, too.
what
happened
to
Lucky?
sloppy
grounding.
582. 52-55 (C)
4/10/01
11:23 AM
Page 1
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