A+: Protect Yourself!
You can best equalize the electrical potential of a computer or component that is being serviced by placing the computer or component on an antistatic work mat equipped with a wrist strap; attach your wrist strap to the mat. This will help place you and the component at the same level of electrical potential, and thus eliminate the “need” for ESD to occur to equalize the potential.
Caution: You should use a commercial wrist strap for most types of computer service, but there is one major exception: Never ground yourself when you are working with high-current devices, such as when you discharge a CRT monitor. Grounding yourself to such devices could cause your body to receive a fatal high-current electrical charge.
For additional safety, use the alligator clip on the antistatic mat to attach to the component or computer you are working on. Attach the clip to unpainted metal on the chassis, such as the frame. This provides superior equalization for the mat, you, and the hardware on the mat.
Table mats connected to a grounded power supply are useful tools for preventing ESD on working computers, especially if users are reminded to touch the mat or grounded keyboard strip first. Antistatic cleaning spray and antistatic carpet spray should be used in any carpeted office to reduce static, especially in the winter when dry heat causes buildup.
Caution: Do not leave the computer plugged in while you work. This does not minimize the chances of ESD, and you could damage equipment if you attach or remove it. This is because virtually all modern computer systems still draw power even when they have been shut down.
Both wrist straps and the work mats include alligator clips that are attached to the system chassis to equalize electrical potential between the wearer and the computer. Wrist straps use hook and loop or other types of adjustable closures; it’s important to wear the wrist strap comfortably snug so that the metal plate underneath the resistor touches the skin to provide proper conductivity.