This is for people who want to upgrade their hardware, have heard that you have to touch something when you work on hardware, but do not know exactely what. Or to those who want to upgrade their PC, bought a certain component, and saw warnings on the packaging that precautions against electrostatic discharges have to be taken while working on hardware.
Due to friction between certain materials (especially in your clothing) you develop an electrostatic potential different than that of your environment. This is called "triboelectric effect". The soles of your shoes insulate you, and when you touch something with your hands, a current will flow through your fingertips. If that something is a piece of RAM or a CPU, you may be out of luck. In order to avoid that you must have at all times the same electrostatic potential as the electronic circuitry you are handling. If you are not "grounded", the current will flow the following way:
[hand]-->[sensitive circuitry]-->[computer case]
The damage threshold for sensitive circuitry protection is about 10 times smaller than the one for human perception of an electrostatic discharge. So you will really find out if your precautions were sufficient when you turn on the machine. Sometimes not even then - very small discharges can do only localized damage that results in erratic performance from your PC.
If you touch the computer case before working, the potential will be equalized and no current will flow when you first touch the circuitry. Ideally, you will have an antistatic wrist band (Figure 2), which you will connect to an unpainted part of the metallic case of the PC. It is also good to power cycle the machine after you have disconnected the power cable. This will equalize the potential inside the PC as well. Theoretically the best way to ground everything is to have both you and the nonpainted PC connected by highly conductive wire to a true grounding device such as an unpainted metal water pipe. This is really going to an extreme length. The grounding wire of an AC plug could be used as well, but this requires you to be truly sure which of the wires in the electrical outlet is the grounding one.
You must also minimize the amount of electrostatic potential created during work. Do not wear wear woolen or synthetic clothes – wear only cotton if possible. Do not remove or put on clothes during hardware work. Do not assemble on the carpet, assemble always on a wooden table or floor (if synthetic top, spread newspapers on it). The antistatic bags that the sensitive circuitry was packaged in can be used to place sensitive components on. Keep plastic objects such as mousemats and telephones away. A very bad creator of static charge is a rolling desk chair. Push it away and stand up while you are working on your PC. Do not allow your cat anywhere near – cats are walking electrostatic generators. During the upgrade work, make sure you touch sensitive circuitry only when necessary. Hold cards by the edges, trying to not touch circuitry. When all is done and you connect the power cord again, first connect the end to the PC, and only after that connect the other end into the wall outlet.
The lower the humidity, the more likely it is that damaging static charges will build up quickly. If your ventilation system allows you to control it, a humidity level between 35 and 50 percent is ideal. If you can't control your humidity, don't do upgrades on a cold winter day when the humidity tends to be very low, or on a warm day with the air conditioning turned up high. If you live in an area where the humidity is generally high, it's not a bad idea to open the windows while you do your upgrades.
Now go ground yourself!