Steve, Well stated and thank you. Some may have the idea that I do not advocate the use of wrist straps. To the contrary, wrist straps are an excellent device and I use one regularly inside the case. But, I know that they do not protect me from electrical shock, and, for that reason, I do the opposite when working around dangerous voltages. I make sure that I am not the shortest path to ground, or even in the path for that matter. I feel it would be a hazard to leave people thinking that such a device strapped to their body would protect them from all electrical shock hazards. You have made that point quite well in your statement. That was the point that I tried to make but may have muddled it in my short response earlier. Thanks again Steve. ...John ----- Original Message ----- From: "Steve Collins" <[log in to unmask]> To: <[log in to unmask]> Sent: Thursday, January 01, 2004 10:48 AM Subject: Re: [PCBUILD] Grounding yourself; Was: Adding memory - grounding yourself > Hi Dean, > > After spending 20 years in the semiconductor industry (including FAB and > Probe & Test), I think that I can consider myself a bit of an ESD expert. > > I think that the confusion here is being caused by the term "grounding". In > this case, the term is not really being used properly (or maybe it's more > accurate to say that it is not being applied properly). Grounding is > required when the potential of some part of an electronic or electrical > circuit must be set at the same potential as the planet Earth. This is > accomplished simply by connecting (or "grounding") that part of the circuit > or component to the planet through a conductive piece of material with a > resistance of less than 1 ohm. > > When dealing with ESD, the concern is not with the grounding of any element. > The concern is with maintaining anything that will touch, or anything that > will come close to each other, at the same electrostatic potential. If you > are grounded through a wrist strap, and your case is sitting at a potential > of 5KV due to electrostatic build-up, then grounding is actually a bad thing > since you will definitely draw an arc as soon as you get close enough to the > case. So, the focus here is to maintain all elements that come in contact > at the same potential: > > Connect your wrist strap to the object that you are working on. In the case > of a computer, clip the strap to a bare piece of metal that is part of the > case. If you have a number of objects that you are working on (e.g. a hard > drive that is to be mounted in the case, new memory, etc.), then place all > objects on a conductive mat and connect your wrist strap to the mat. It is > NOT necessary to ground any part of this setup. Remember that the object is > simply to bring all elements to the same potential. We never recommend > using any part of a live circuit (including house wiring) for any purpose > other than providing power to an electrical instrument or appliance. NEVER > connect a living thing to your house wiring. This includes the cat, the > fish, the canary and, oh yes, YOU! If you require a ground reference, > install a separate ground bus that is not part of, or near, your house > wiring. NEVER remove, install or replace components on a device that is > connected to a source of power (i.e. ALWAYS unplug the power supply before > doing any component work). > > Follow these simple rules and you and your components will live to see > another day. > > Regards, > Steve Collins > AlternateRealities - High Performance Computers, Clusters and > Infrastructures > Phone: (819)669-8885 > Fax: (819)669-8887 > e-mail: [log in to unmask] > URL: http://www.AlternateRealities.ca > > > > -----Original Message----- > > From: PCBUILD - Personal Computer Hardware discussion List > > [mailto:[log in to unmask]] On Behalf Of Dean Kukral > > Sent: Thursday, January 01, 2004 9:45 AM > > To: [log in to unmask] > > Subject: [PCBUILD] Grounding yourself; Was: Adding memory - > > grounding yourself > > > > What if you have a faulty device in your house with a short > > (fault) to ground? It is **possible** for the ground wire to > > be hot, isn't it? I know it is not likely, and even if you > > got shocked, it would not likely be serious, but for the > > average guy who works on his computer only now and then, I > > think that a wrist strap connected to the case is the better choice. > > The problem is ESD. On a case with many sharp corners and > > edges, electrostatic charge is quickly dissipated. > > > > Are there any electricians out there who can tell us if I am > > being anal about this? > > > > Dean Kukral > > The NOSPIN Group is now offering Free PC Tech > support at our newest website: > http://freepctech.com > The NOSPIN Group is now offering Free PC Tech support at our newest website: http://freepctech.com