Folks,
Remember that the basic requirement for ESD protection at the workbench
is that everything in the work area should be at the *same* potential.
That potential does not have to be at absolute zero reference volts, and
the grounding leads do not have to carry more than a few microamps - the
mats and straps are to be grounded through 1 megohm resistors (usually
built-in) so the currents are limited.
Of course, you should check to be certain that the ground lead on your
electrical plugs in the work area (and the rest of your house too) are
actually connected. Get one of those little outlet testers that plug
into the receptacle and indicate its state with LEDs.
As long as the outlets are grounded, you can use that ground as an
adequate grounding terminal for ESD protection in your work area, with
standard receptacles in the US, the duplex receptacle plate mounting
screw provides a good ground connection point.
There is no need to drive rounding rods and run separate grounds for
this purpose. In the shack where you have antennas coming in, a
different situation exists, and proper lightning protection is prudent,
but that is different than ESD protection in the work area.
73,
Don W3FPR
Fred (FL) wrote:
",,,,,,,,,, Connect to the House Mains" (connection
thru one's 110VAC outlet)
Problem, or potential problems with this "ground (thru
a resistor) connection" - it assumes some electrician
didn't mess up and not connect that plug's ground.
It is common home electical "code" - that one should
not count on having a continuous or present ground
connection, at every plug in a home. Some may be
mis-wired, some may be open, some may have been
wired wrong, some may have opened over time.
To exasterbate (sp?) the safety problem further -
almost every home in the U.S. can have a different
connection to earth ground - be it a 6 foot copper rod
at outlet box, or they relied on the 8 foot
copper-plated rod at the nearest transformer pole, or
some other "ground" connection somewhere that power
company's felt should be operable. Your home's ground
therefore - could actually be .14 VAC, etc.
Medical experts say it only takes milliamp currents,
thru one's heart - to kill a person.
Some so-called ground connections, can actually be
several volts above or below "zero volts". Ala -
old homes, and facilities.
FOR THESE REASONS - It appears strongly recommend
every ham, with a ham station, should install one or
more local copper ground rods near their shack, and
use them accordingly. "earth grounds"
Electricians are only human - I took their license
code course a couple years back in 2001. I'm an EE,
but if there is a licensed electrician on this list -
possibly they could educate us all on this one!
Question really is: HOW DOES ONE ENSURE HIS HOME, and
SHACK PLUGS - actually are connected to ZERO
VOLT REAL GROUND, AS CODE SAYS THEY SHOULD BE?
Fred, N3CSY, NY
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