Legion6789 wrote:
I guess it surprised me a little as I routinely assemble PCs and never give a second thought to handling CPUs, video cards, etc without any kind of static protection. To date, I've never encountered an issue.
Once they're in circuits, they're less vulnerable. For one thing, if there are lots of things on a bus line, and each of them has protection diodes, there's more protection. Next, if you reach into a PC with the cover off, you'll usually touch the case first, even if unintentionally, bringing the PC's ground and your body to the same potential. When handling cards that are not in the PC, I always touch the metal strip at the back first, for the same reason.
Quote:
Does the wrist strap need to be grounded to true earth ground via an outlet's ground plug? Or is something like the metal table leg good enough?
There's usually a place to snap the strap onto the mat. Ideally the mat has a cord to ground (and yes, the ground prong of wall outlets normally qualifies); but even if it does not have such a cord, often it will get an equivalent grounding through equipment that's sitting on it, if the equipment has 3-prong power cords. In my case, I have two oscilloscopes with metal tilt-up bars that are sitting on the mats, and these go to the oscilloscopes' chasis, which get grounded through the power cords. If yours have plastic insulation between, well, beware. I also have a separate cord from the mats to an alligator clip which goes to the ground lug on the front of one of the 'scopes. The electrical in the room I'm in, built in 1949, does not have grounded outlets, so I puta wire to a ground rod pounded into the dirt just outside. We have another ground rod next to the garage (maybe 70 feet away) where the phone line comes in, and I was surprised to find there was well under ten ohms between the two rods, even though it had not rained for months when I measured! (A really low resistance is not necessary just to discharge static though.)
My main soldering iron does not have a ground prong, so I put a separate wire from its heater to an alligator clip which I clip onto the edge of one of the mats.