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Old February 6th, 2008, 21:30   #19
MadMax
Delierious Designer of Dastardly Detonations
 
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Join Date: Dec 2001
Location: in the dark recesses of some metal chip filled machine shop
A very conductive top isn't the best situation either. If your board is charged to some potential, it will discharge quickly when it arcs to your grounded metal table. Also, a powered circuit can short through your table surface. Still a conductive table works well if you don't troubleshoot powered boards that can contact the table. Putting a PTW on a grounded steel top will bring it to ground before you dig around the circuits so if you rest your elbows on it you'll be at the same potential.

The best surface is mildly conductive (around 1megOhm/cm I think). Not conductive enough to short most ccts, conductive enough to gradually dissapate an ES buildup, resistive enough to provide a super easy grounding potential for a spark.

A good ESD mat runs around $40 online and a wrist strap under $10. Besides PTWs I do a lot of electronics rework so it was an easy decision to go with. Go with a rubber mat instead of a vinyl one as they resist melting better (hot solder splats).

Quote:
Originally Posted by mcguyver View Post
It's not an issue for me. My workbench is steel and bonded to ground. Any static will be shunted to ground as soon as I touch my bench. Any metal workbench with any electric devices on it (mounted worklights, receptacles, etc.) and manufactured to meet CSA standards must be bonded to ground. Even if you retrofit one yourself, it must meet CEC in Canada and be bonded to ground.

And grab any boards by their sides. There is never a need to touch the components or traces.
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