By Joe Stoddard
Hi Joe,
I was just reading your 12/30/97 article "RAM: How much is enough?" I ran across a statement at the end of the article that I felt should be addressed. When you were talking about grounding so as not to zap the chips you stated: "You can ground yourself by wrapping a copper wire around your pinky, and tying it off at a known ground (the cover plate screw of a grounded outlet, for example)."
This can be a very dangerous practice!! If the outlet happens to have an electrical fault or if a power surge runs through the lines there is a possibility that the "attached" person could be injured or killed.
I wrote all of the Electro Static Discharge (ESD) procedures for two different companies that I worked for. There is now grounding equipment that a person may come in contact with that is a straight run to ground. All static wrist straps on the market contain a 1MegOhm (1,000,000 Ohm) resistor in the cord. This is to ensure that the user does not get electrocuted by a short or power surge. The resistor allows the voltage to pass through the strap in a case like this but the resistance is high enough that the current is diminished to a non-harmful level. Also the wires of these straps are very thin. If the resistor does for some reason short, a voltage spike would melt the wires in two so once again no harm would come to the user.
These devices have been developed under very strict safety standards to keep people from harm. They range from inexpensive disposable models to durable metal watch band styles. I would suggest to your readers to go to a computer store, or an electronics store and pick one up before trying to work on their systems. The cost is a good insurance policy for both their equipment and their safety.
For a strap to be effective the following guidelines should be followed:
1)Test the wrist strap before every use to make sure it is working. 2)Wear the strap directly on the skin for the best contact.
3)Wear a short sleeve cotton shirt when working on electronic equipment (Cotton generates less static than other types of cloth).
4)Ground yourself and the bag the components come in to the equipment being worked on for a minimum of 3 seconds to drain the charge away from the outside of the bag, the equipment and yourself.
Following these steps will help assure that your upgrade will be safe and your parts will still work.
Chuck Lottermoser
Quality Assurance Engineer
Joe Stoddard is a Certified Professional Building Designer and writes frequently about computers for the building industry.
