[Elecraft] Being ESD Safe

[Don Wilhelm]

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
>